Import thekla_atlas

As requested by reduz, an import of thekla_atlas into thirdparty/

48 files changed, 11440 insertions, 0 deletions

diff --git a/thirdparty/thekla_atlas/nvmesh/BaseMesh.cpp b/thirdparty/thekla_atlas/nvmesh/BaseMesh.cpp
new file mode 100644
index 0000000000..f17d3b46fd
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/BaseMesh.cpp
@@ -0,0 +1,19 @@
+// This code is in the public domain -- Ignacio Castaņo <castano@gmail.com>
+
+#include "BaseMesh.h"
+#include "Stream.h"
+#include "nvmath/TypeSerialization.h"
+
+
+namespace nv
+{
+	static Stream & operator<< (Stream & s, BaseMesh::Vertex & vertex)
+	{
+		return s << vertex.id << vertex.pos << vertex.nor << vertex.tex;
+	}
+
+	Stream & operator<< (Stream & s, BaseMesh & mesh)
+	{
+		return s << mesh.m_vertexArray;
+	}
+}
diff --git a/thirdparty/thekla_atlas/nvmesh/BaseMesh.h b/thirdparty/thekla_atlas/nvmesh/BaseMesh.h
new file mode 100644
index 0000000000..c8559511f1
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/BaseMesh.h
@@ -0,0 +1,72 @@
+// This code is in the public domain -- Ignacio Castaņo <castano@gmail.com>
+
+#pragma once
+#ifndef NV_MESH_BASEMESH_H
+#define NV_MESH_BASEMESH_H
+
+#include "nvmesh.h"
+#include "nvmath/Vector.h"
+#include "nvcore/Array.h"
+#include "nvcore/Hash.h"
+
+namespace nv
+{
+
+    /// Base mesh without connectivity.
+    class BaseMesh
+    {
+    public:
+        struct Vertex;
+
+        BaseMesh() {}
+
+        BaseMesh(uint vertexNum) :
+            m_vertexArray(vertexNum) {}
+
+        // Vertex methods.
+        uint vertexCount() const { return m_vertexArray.count(); }
+        const Vertex & vertexAt(uint i) const { return m_vertexArray[i]; }
+        Vertex & vertexAt(uint i) { return m_vertexArray[i]; }
+        const Array<Vertex> & vertices() const { return m_vertexArray; }
+        Array<Vertex> & vertices() { return m_vertexArray; }
+
+        friend Stream & operator<< (Stream & s, BaseMesh & obj);
+
+    protected:
+
+        Array<Vertex> m_vertexArray;
+    };
+
+
+    /// BaseMesh vertex.
+    struct BaseMesh::Vertex
+    {
+        Vertex() : id(NIL), pos(0.0f), nor(0.0f), tex(0.0f) {}
+
+        uint id;		// @@ Vertex should be an index into the vertex data.
+        Vector3 pos;
+        Vector3 nor;
+        Vector2 tex;
+    };
+
+    inline bool operator==(const BaseMesh::Vertex & a, const BaseMesh::Vertex & b)
+    {
+        return a.pos == b.pos && a.nor == b.nor && a.tex == b.tex;
+    }
+
+    inline bool operator!=(const BaseMesh::Vertex & a, const BaseMesh::Vertex & b)
+    {
+        return a.pos != b.pos && a.nor != b.nor && a.tex != b.tex;
+    }
+
+    template <> struct Hash<BaseMesh::Vertex>
+    {
+        uint operator()(const BaseMesh::Vertex & v) const
+        {
+            return Hash<Vector3>()(v.pos);
+        }
+    };
+
+} // nv namespace
+
+#endif // NV_MESH_BASEMESH_H
diff --git a/thirdparty/thekla_atlas/nvmesh/MeshBuilder.cpp b/thirdparty/thekla_atlas/nvmesh/MeshBuilder.cpp
new file mode 100644
index 0000000000..24d8ddff89
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/MeshBuilder.cpp
@@ -0,0 +1,1000 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#include "nvmesh.h" // pch
+
+#include "MeshBuilder.h"
+#include "TriMesh.h"
+#include "QuadTriMesh.h"
+#include "halfedge/Mesh.h"
+#include "halfedge/Vertex.h"
+#include "halfedge/Face.h"
+
+#include "weld/Weld.h"
+
+#include "nvmath/Box.h"
+#include "nvmath/Vector.inl"
+
+#include "nvcore/StrLib.h"
+#include "nvcore/RadixSort.h"
+#include "nvcore/Ptr.h"
+#include "nvcore/Array.inl"
+#include "nvcore/HashMap.inl"
+
+
+using namespace nv;
+
+/*
+By default the mesh builder creates 3 streams (position, normal, texcoord), I'm planning to add support for extra streams as follows:
+
+enum StreamType { StreamType_Float, StreamType_Vector2, StreamType_Vector3, StreamType_Vector4 };
+
+uint addStream(const char *, uint idx, StreamType);
+
+uint addAttribute(float)
+uint addAttribute(Vector2)
+uint addAttribute(Vector3)
+uint addAttribute(Vector4)
+
+struct Vertex
+{
+    uint pos;
+    uint nor;
+    uint tex;
+    uint * attribs;	// NULL or NIL terminated array?
+};
+
+All streams must be added before hand, so that you know the size of the attribs array.
+
+The vertex hash function could be kept as is, but the == operator should be extended to test 
+the extra atributes when available.
+
+That might require a custom hash implementation, or an extension of the current one. How to
+handle the variable number of attributes in the attribs array?
+
+bool operator()(const Vertex & a, const Vertex & b) const
+{ 
+    if (a.pos != b.pos || a.nor != b.nor || a.tex != b.tex) return false;
+    if (a.attribs == NULL && b.attribs == NULL) return true;
+    return 0 == memcmp(a.attribs, b.attribs, ???);
+}
+
+We could use a NIL terminated array, or provide custom user data to the equals functor.
+
+vertexMap.setUserData((void *)vertexAttribCount);
+
+bool operator()(const Vertex & a, const Vertex & b, void * userData) const { ... }
+
+*/
+
+
+
+namespace 
+{
+    struct Material
+    {
+        Material() : faceCount(0) {}
+        Material(const String & str) : name(str), faceCount(0) {}
+
+        String name;
+        uint faceCount;
+    };
+
+    struct Vertex
+    {
+        //Vertex() {}
+        //Vertex(uint p, uint n, uint t0, uint t1, uint c) : pos(p), nor(n), tex0(t0), tex1(t1), col(c) {}
+
+        friend bool operator==(const Vertex & a, const Vertex & b)
+        {
+            return a.pos == b.pos && a.nor == b.nor && a.tex[0] == b.tex[0] && a.tex[1] == b.tex[1] && a.col[0] == b.col[0] && a.col[1] == b.col[1] && a.col[2] == b.col[2];
+        }
+
+        uint pos;
+        uint nor;
+        uint tex[2];
+        uint col[3];
+    };
+
+    struct Face
+    {
+        uint id;
+        uint firstIndex;
+        uint indexCount;
+        uint material;
+        uint group;
+    };
+
+} // namespace
+
+
+namespace nv
+{
+    // This is a much better hash than the default and greatly improves performance!
+    template <> struct Hash<Vertex>
+    {
+        uint operator()(const Vertex & v) const { return v.pos + v.nor + v.tex[0]/* + v.col*/; }
+    };
+}
+
+struct MeshBuilder::PrivateData
+{
+    PrivateData() : currentGroup(NIL), currentMaterial(NIL), maxFaceIndexCount(0) {}
+
+    uint pushVertex(uint p, uint n, uint t0, uint t1, uint c0, uint c1, uint c2);
+    uint pushVertex(const Vertex & v);
+
+    Array<Vector3> posArray;
+    Array<Vector3> norArray;
+    Array<Vector2> texArray[2];
+    Array<Vector4> colArray[3];
+
+    Array<Vertex> vertexArray;
+    HashMap<Vertex, uint> vertexMap;
+
+    HashMap<String, uint> materialMap;
+    Array<Material> materialArray;
+
+    uint currentGroup;
+    uint currentMaterial;
+
+    Array<uint> indexArray;
+    Array<Face> faceArray;
+
+    uint maxFaceIndexCount;
+};
+
+
+uint MeshBuilder::PrivateData::pushVertex(uint p, uint n, uint t0, uint t1, uint c0, uint c1, uint c2)
+{
+    Vertex v;
+    v.pos = p;
+    v.nor = n;
+    v.tex[0] = t0;
+    v.tex[1] = t1;
+    v.col[0] = c0;
+    v.col[1] = c1;
+    v.col[2] = c2;
+    return pushVertex(v);
+}
+
+uint MeshBuilder::PrivateData::pushVertex(const Vertex & v)
+{
+    // Lookup vertex v in map.
+    uint idx;
+    if (vertexMap.get(v, &idx))
+    {
+        return idx;
+    }
+
+    idx = vertexArray.count();
+    vertexArray.pushBack(v);
+    vertexMap.add(v, idx);
+
+    return idx;
+}
+
+
+MeshBuilder::MeshBuilder() : d(new PrivateData())
+{
+}
+
+MeshBuilder::~MeshBuilder()
+{
+    nvDebugCheck(d != NULL);
+    delete d;
+}
+
+
+// Builder methods.
+uint MeshBuilder::addPosition(const Vector3 & v)
+{
+    d->posArray.pushBack(validate(v));
+    return d->posArray.count() - 1;
+}
+
+uint MeshBuilder::addNormal(const Vector3 & v)
+{
+    d->norArray.pushBack(validate(v));
+    return d->norArray.count() - 1;
+}
+
+uint MeshBuilder::addTexCoord(const Vector2 & v, uint set/*=0*/)
+{
+    d->texArray[set].pushBack(validate(v));
+    return d->texArray[set].count() - 1;
+}
+
+uint MeshBuilder::addColor(const Vector4 & v, uint set/*=0*/)
+{
+    d->colArray[set].pushBack(validate(v));
+    return d->colArray[set].count() - 1;
+}
+
+void MeshBuilder::beginGroup(uint id)
+{
+    d->currentGroup = id;
+}
+
+void MeshBuilder::endGroup()
+{
+    d->currentGroup = NIL;
+}
+
+// Add named material, check for uniquenes.
+uint MeshBuilder::addMaterial(const char * name)
+{
+    uint index;
+    if (d->materialMap.get(name, &index)) {
+        nvDebugCheck(d->materialArray[index].name == name);
+    }
+    else {
+        index = d->materialArray.count();
+        d->materialMap.add(name, index);
+        
+        Material material(name);
+        d->materialArray.append(material);
+    }
+    return index;
+}
+
+void MeshBuilder::beginMaterial(uint id)
+{
+    d->currentMaterial = id;
+}
+
+void MeshBuilder::endMaterial()
+{
+    d->currentMaterial = NIL;
+}
+
+void MeshBuilder::beginPolygon(uint id/*=0*/)
+{
+    Face face;
+    face.id = id;
+    face.firstIndex = d->indexArray.count();
+    face.indexCount = 0;
+    face.material = d->currentMaterial;
+    face.group = d->currentGroup;
+
+    d->faceArray.pushBack(face);
+}
+
+uint MeshBuilder::addVertex(uint p, uint n/*= NIL*/, uint t0/*= NIL*/, uint t1/*= NIL*/, uint c0/*= NIL*/, uint c1/*= NIL*/, uint c2/*= NIL*/)
+{
+    // @@ In theory there's no need to add vertices before faces, but I'm adding this to debug problems in our maya exporter:
+    nvDebugCheck(p < d->posArray.count());
+    nvDebugCheck(n == NIL || n < d->norArray.count());
+    nvDebugCheck(t0 == NIL || t0 < d->texArray[0].count());
+    nvDebugCheck(t1 == NIL || t1 < d->texArray[1].count());
+    //nvDebugCheck(c0 == NIL || c0 < d->colArray[0].count());
+    if (c0 > d->colArray[0].count()) c0 = NIL;    // @@ This seems to be happening in loc_swamp_catwalk.mb! No idea why.
+    nvDebugCheck(c1 == NIL || c1 < d->colArray[1].count());
+    nvDebugCheck(c2 == NIL || c2 < d->colArray[2].count());
+
+    uint idx = d->pushVertex(p, n, t0, t1, c0, c1, c2);
+    d->indexArray.pushBack(idx);
+    d->faceArray.back().indexCount++;
+    return idx;
+}
+
+uint MeshBuilder::addVertex(const Vector3 & pos)
+{
+    uint p = addPosition(pos);
+    return addVertex(p);
+}
+
+#if 0
+uint MeshBuilder::addVertex(const Vector3 & pos, const Vector3 & nor, const Vector2 & tex0, const Vector2 & tex1, const Vector4 & col0, const Vector4 & col1)
+{
+    uint p = addPosition(pos);
+    uint n = addNormal(nor);
+    uint t0 = addTexCoord(tex0, 0);
+    uint t1 = addTexCoord(tex1, 1);
+    uint c0 = addColor(col0);
+    uint c1 = addColor(col1);
+    return addVertex(p, n, t0, t1, c0, c1);
+}
+#endif
+
+// Return true if the face is valid and was added to the mesh.
+bool MeshBuilder::endPolygon()
+{
+    const Face & face = d->faceArray.back();
+    const uint count = face.indexCount;
+
+    // Validate polygon here.
+    bool invalid = count <= 2;
+
+    if (!invalid) {
+        // Skip zero area polygons. Or polygons with degenerate edges (which will result in zero-area triangles).
+        const uint first = face.firstIndex;
+        for (uint j = count - 1, i = 0; i < count; j = i, i++) {
+            uint v0 = d->indexArray[first + i];
+            uint v1 = d->indexArray[first + j];
+
+            uint p0 = d->vertexArray[v0].pos;
+            uint p1 = d->vertexArray[v1].pos;
+
+            if (p0 == p1) {
+                invalid = true;
+                break;
+            }
+
+            if (equal(d->posArray[p0], d->posArray[p1], FLT_EPSILON)) {
+                invalid = true;
+                break;
+            }
+        }
+
+        uint v0 = d->indexArray[first];
+        uint p0 = d->vertexArray[v0].pos;
+        Vector3 x0 = d->posArray[p0];
+
+        float area = 0.0f;
+        for (uint j = 1, i = 2; i < count; j = i, i++) {
+            uint v1 = d->indexArray[first + i];
+            uint v2 = d->indexArray[first + j];
+
+            uint p1 = d->vertexArray[v1].pos;
+            uint p2 = d->vertexArray[v2].pos;
+
+            Vector3 x1 = d->posArray[p1];
+            Vector3 x2 = d->posArray[p2];
+
+            area += length(cross(x1-x0, x2-x0));
+        }
+
+        if (0.5 * area < 1e-6) {    // Reduce this threshold if artists have legitimate complains.
+            invalid = true;
+        }
+
+        // @@ This is not complete. We may still get zero area triangles after triangulation.
+        // However, our plugin triangulates before building the mesh, so hopefully that's not a problem.
+
+    }
+
+    if (invalid)
+    {
+        d->indexArray.resize(d->indexArray.size() - count);
+        d->faceArray.popBack();
+        return false;
+    }
+    else
+    {
+        if (d->currentMaterial != NIL) {
+            d->materialArray[d->currentMaterial].faceCount++;
+        }
+
+        d->maxFaceIndexCount = max(d->maxFaceIndexCount, count);
+        return true;
+    }
+}
+
+
+uint MeshBuilder::weldPositions()
+{
+    Array<uint> xrefs;
+    Weld<Vector3> weldVector3;
+
+    if (d->posArray.count()) {
+        // Weld vertex attributes.
+        weldVector3(d->posArray, xrefs);
+
+        // Remap vertex indices.
+        const uint vertexCount = d->vertexArray.count();
+        for (uint v = 0; v < vertexCount; v++)
+        {
+            Vertex & vertex = d->vertexArray[v];
+            if (vertex.pos != NIL) vertex.pos = xrefs[vertex.pos];
+        }
+    }
+
+    return d->posArray.count();
+}
+
+uint MeshBuilder::weldNormals()
+{
+    Array<uint> xrefs;
+    Weld<Vector3> weldVector3;
+
+    if (d->norArray.count()) {
+        // Weld vertex attributes.
+        weldVector3(d->norArray, xrefs);
+
+        // Remap vertex indices.
+        const uint vertexCount = d->vertexArray.count();
+        for (uint v = 0; v < vertexCount; v++)
+        {
+            Vertex & vertex = d->vertexArray[v];
+            if (vertex.nor != NIL) vertex.nor = xrefs[vertex.nor];
+        }
+    }
+
+    return d->norArray.count();
+}
+
+uint MeshBuilder::weldTexCoords(uint set/*=0*/)
+{
+    Array<uint> xrefs;
+    Weld<Vector2> weldVector2;
+
+    if (d->texArray[set].count()) {
+        // Weld vertex attributes.
+        weldVector2(d->texArray[set], xrefs);
+
+        // Remap vertex indices.
+        const uint vertexCount = d->vertexArray.count();
+        for (uint v = 0; v < vertexCount; v++)
+        {
+            Vertex & vertex = d->vertexArray[v];
+            if (vertex.tex[set] != NIL) vertex.tex[set] = xrefs[vertex.tex[set]];
+        }
+    }
+
+    return d->texArray[set].count();
+}
+
+uint  MeshBuilder::weldColors(uint set/*=0*/)
+{
+    Array<uint> xrefs;
+    Weld<Vector4> weldVector4;
+
+    if (d->colArray[set].count()) {
+        // Weld vertex attributes.
+        weldVector4(d->colArray[set], xrefs);
+
+        // Remap vertex indices.
+        const uint vertexCount = d->vertexArray.count();
+        for (uint v = 0; v < vertexCount; v++)
+        {
+            Vertex & vertex = d->vertexArray[v];
+            if (vertex.col[set] != NIL) vertex.col[set] = xrefs[vertex.col[set]];
+        }
+    }
+
+    return d->colArray[set].count();
+}
+
+void MeshBuilder::weldVertices() {
+
+    if (d->vertexArray.count() == 0) {
+        // Nothing to do.
+        return;
+    }
+
+    Array<uint> xrefs;
+    Weld<Vertex> weldVertex;
+
+    // Weld vertices.
+    weldVertex(d->vertexArray, xrefs);
+
+    // Remap face indices.
+    const uint indexCount = d->indexArray.count();
+    for (uint i = 0; i < indexCount; i++)
+    {
+        d->indexArray[i] = xrefs[d->indexArray[i]];
+    }
+
+    // Remap vertex map.
+    foreach(i, d->vertexMap)
+    {
+        d->vertexMap[i].value = xrefs[d->vertexMap[i].value];
+    }
+}
+
+
+void MeshBuilder::optimize()
+{
+    if (d->vertexArray.count() == 0)
+    {
+        return;
+    }
+
+    weldPositions();
+    weldNormals();
+    weldTexCoords(0);
+    weldTexCoords(1);
+    weldColors();
+
+    weldVertices();
+}
+
+
+
+
+
+
+void MeshBuilder::removeUnusedMaterials(Array<uint> & newMaterialId)
+{
+    uint materialCount = d->materialArray.count();
+
+    // Reset face counts.
+    for (uint i = 0; i < materialCount; i++) {
+        d->materialArray[i].faceCount = 0;
+    }
+
+    // Count faces.
+    foreach(i, d->faceArray) {
+        Face & face = d->faceArray[i];
+
+        if (face.material != NIL) {
+            nvDebugCheck(face.material < materialCount);
+
+            d->materialArray[face.material].faceCount++;
+        }
+    }
+
+    // Remove unused materials.
+    newMaterialId.resize(materialCount);
+
+    for (uint i = 0, m = 0; i < materialCount; i++)
+    {
+        if (d->materialArray[m].faceCount > 0)
+        {
+            newMaterialId[i] = m++;
+        }
+        else
+        {
+            newMaterialId[i] = NIL;
+            d->materialArray.removeAt(m);
+        }
+    }
+
+    materialCount = d->materialArray.count();
+
+    // Update face material ids.
+    foreach(i, d->faceArray) {
+        Face & face = d->faceArray[i];
+
+        if (face.material != NIL) {
+            uint id = newMaterialId[face.material];
+            nvDebugCheck(id != NIL && id < materialCount);
+
+            face.material = id;
+        }
+    }
+}
+
+void MeshBuilder::sortFacesByGroup()
+{
+    const uint faceCount = d->faceArray.count();
+
+    Array<uint> faceGroupArray;
+    faceGroupArray.resize(faceCount);
+    
+    for (uint i = 0; i < faceCount; i++) {
+        faceGroupArray[i] = d->faceArray[i].group;
+    }
+
+    RadixSort radix;
+    radix.sort(faceGroupArray);
+
+    Array<Face> newFaceArray;
+    newFaceArray.resize(faceCount);
+
+    for (uint i = 0; i < faceCount; i++) {
+        newFaceArray[i] = d->faceArray[radix.rank(i)];
+    }
+
+    swap(newFaceArray, d->faceArray);
+}
+
+void MeshBuilder::sortFacesByMaterial()
+{
+    const uint faceCount = d->faceArray.count();
+
+    Array<uint> faceMaterialArray;
+    faceMaterialArray.resize(faceCount);
+    
+    for (uint i = 0; i < faceCount; i++) {
+        faceMaterialArray[i] = d->faceArray[i].material;
+    }
+
+    RadixSort radix;
+    radix.sort(faceMaterialArray);
+
+    Array<Face> newFaceArray;
+    newFaceArray.resize(faceCount);
+
+    for (uint i = 0; i < faceCount; i++) {
+        newFaceArray[i] = d->faceArray[radix.rank(i)];
+    }
+
+    swap(newFaceArray, d->faceArray);
+}
+
+
+void MeshBuilder::reset()
+{
+    nvDebugCheck(d != NULL);
+    delete d;
+    d = new PrivateData();
+}
+
+void MeshBuilder::done()
+{
+    if (d->currentGroup != NIL) {
+        endGroup();
+    }
+
+    if (d->currentMaterial != NIL) {
+        endMaterial();
+    }
+}
+
+// Hints.
+void MeshBuilder::hintTriangleCount(uint count)
+{
+    d->indexArray.reserve(d->indexArray.count() + count * 4);
+}
+
+void MeshBuilder::hintVertexCount(uint count)
+{
+    d->vertexArray.reserve(d->vertexArray.count() + count);
+    d->vertexMap.resize(d->vertexMap.count() + count);
+}
+
+void MeshBuilder::hintPositionCount(uint count)
+{
+    d->posArray.reserve(d->posArray.count() + count);
+}
+
+void MeshBuilder::hintNormalCount(uint count)
+{
+    d->norArray.reserve(d->norArray.count() + count);
+}
+
+void MeshBuilder::hintTexCoordCount(uint count, uint set/*=0*/)
+{
+    d->texArray[set].reserve(d->texArray[set].count() + count);
+}
+
+void MeshBuilder::hintColorCount(uint count, uint set/*=0*/)
+{
+    d->colArray[set].reserve(d->colArray[set].count() + count);
+}
+
+
+// Helpers.
+void MeshBuilder::addTriangle(uint v0, uint v1, uint v2)
+{
+    beginPolygon();
+    addVertex(v0);
+    addVertex(v1);
+    addVertex(v2);
+    endPolygon();
+}
+
+void MeshBuilder::addQuad(uint v0, uint v1, uint v2, uint v3)
+{
+    beginPolygon();
+    addVertex(v0);
+    addVertex(v1);
+    addVertex(v2);
+    addVertex(v3);
+    endPolygon();
+}
+
+
+// Get tri mesh.
+TriMesh * MeshBuilder::buildTriMesh() const
+{
+    const uint faceCount = d->faceArray.count();
+    uint triangleCount = 0;
+    for (uint f = 0; f < faceCount; f++) {
+        triangleCount += d->faceArray[f].indexCount - 2;
+    }
+    
+    const uint vertexCount = d->vertexArray.count();
+    TriMesh * mesh = new TriMesh(triangleCount, vertexCount);
+
+    // Build faces.
+    Array<TriMesh::Face> & faces = mesh->faces();
+
+    for(uint f = 0; f < faceCount; f++)
+    {
+        int firstIndex = d->faceArray[f].firstIndex;
+        int indexCount = d->faceArray[f].indexCount;
+
+        int v0 = d->indexArray[firstIndex + 0];
+        int v1 = d->indexArray[firstIndex + 1];
+
+        for(int t = 0; t < indexCount - 2; t++) {
+            int v2 = d->indexArray[firstIndex + t + 2];
+
+            TriMesh::Face face;
+            face.id = faces.count();
+            face.v[0] = v0;
+            face.v[1] = v1;
+            face.v[2] = v2;
+            faces.append(face);
+
+            v1 = v2;
+        }
+    }
+
+    // Build vertices.
+    Array<BaseMesh::Vertex> & vertices = mesh->vertices();
+
+    for(uint i = 0; i < vertexCount; i++)
+    {
+        BaseMesh::Vertex vertex;
+        vertex.id = i;
+        if (d->vertexArray[i].pos != NIL) vertex.pos = d->posArray[d->vertexArray[i].pos];
+        if (d->vertexArray[i].nor != NIL) vertex.nor = d->norArray[d->vertexArray[i].nor];
+        if (d->vertexArray[i].tex[0] != NIL) vertex.tex = d->texArray[0][d->vertexArray[i].tex[0]];
+
+        vertices.append(vertex);
+    }
+
+    return mesh;
+}
+
+// Get quad/tri mesh.
+QuadTriMesh * MeshBuilder::buildQuadTriMesh() const
+{
+    const uint faceCount = d->faceArray.count();
+    const uint vertexCount = d->vertexArray.count();
+    QuadTriMesh * mesh = new QuadTriMesh(faceCount, vertexCount);
+
+    // Build faces.
+    Array<QuadTriMesh::Face> & faces = mesh->faces();
+
+    for (uint f = 0; f < faceCount; f++) 
+    {
+        int firstIndex = d->faceArray[f].firstIndex;
+        int indexCount = d->faceArray[f].indexCount;
+
+        QuadTriMesh::Face face;
+        face.id = f;
+
+        face.v[0] = d->indexArray[firstIndex + 0];
+        face.v[1] = d->indexArray[firstIndex + 1];
+        face.v[2] = d->indexArray[firstIndex + 2];
+
+        // Only adds triangles and quads. Ignores polygons.
+        if (indexCount == 3) {
+            face.v[3] = NIL;
+            faces.append(face);
+        }
+        else if (indexCount == 4) {
+            face.v[3] = d->indexArray[firstIndex + 3];
+            faces.append(face);
+        }
+    }
+
+    // Build vertices.
+    Array<BaseMesh::Vertex> & vertices = mesh->vertices();
+
+    for(uint i = 0; i < vertexCount; i++)
+    {
+        BaseMesh::Vertex vertex;
+        vertex.id = i;
+        if (d->vertexArray[i].pos != NIL) vertex.pos = d->posArray[d->vertexArray[i].pos];
+        if (d->vertexArray[i].nor != NIL) vertex.nor = d->norArray[d->vertexArray[i].nor];
+        if (d->vertexArray[i].tex[0] != NIL) vertex.tex = d->texArray[0][d->vertexArray[i].tex[0]];
+
+        vertices.append(vertex);
+    }
+
+    return mesh;
+}
+
+// Get half edge mesh.
+HalfEdge::Mesh * MeshBuilder::buildHalfEdgeMesh(bool weldPositions, Error * error/*=NULL*/, Array<uint> * badFaces/*=NULL*/) const
+{
+    if (error != NULL) *error = Error_None;
+
+    const uint vertexCount = d->vertexArray.count();
+    AutoPtr<HalfEdge::Mesh> mesh(new HalfEdge::Mesh());
+
+    for(uint v = 0; v < vertexCount; v++)
+    {
+        HalfEdge::Vertex * vertex = mesh->addVertex(d->posArray[d->vertexArray[v].pos]);
+        if (d->vertexArray[v].nor != NIL) vertex->nor = d->norArray[d->vertexArray[v].nor];
+        if (d->vertexArray[v].tex[0] != NIL) vertex->tex = Vector2(d->texArray[0][d->vertexArray[v].tex[0]]);
+        if (d->vertexArray[v].col[0] != NIL) vertex->col = d->colArray[0][d->vertexArray[v].col[0]];
+    }
+
+    if (weldPositions) {
+        mesh->linkColocals();
+    }
+    else {
+        // Build canonical map from position indices.
+        Array<uint> canonicalMap(vertexCount);
+        
+        foreach (i, d->vertexArray) {
+            canonicalMap.append(d->vertexArray[i].pos);
+        }
+
+        mesh->linkColocalsWithCanonicalMap(canonicalMap);
+    }
+
+    const uint faceCount = d->faceArray.count();
+    for (uint f = 0; f < faceCount; f++)
+    {
+        const uint firstIndex = d->faceArray[f].firstIndex;
+        const uint indexCount = d->faceArray[f].indexCount;
+
+        HalfEdge::Face * face = mesh->addFace(d->indexArray, firstIndex, indexCount);
+        
+        // @@ This is too late, removing the face here will leave the mesh improperly connected.
+        /*if (face->area() <= FLT_EPSILON) {
+            mesh->remove(face);
+            face = NULL;
+        }*/
+
+        if (face == NULL) {
+            // Non manifold mesh.
+            if (error != NULL) *error = Error_NonManifoldEdge;
+            if (badFaces != NULL) {
+                badFaces->append(d->faceArray[f].id);
+            }
+            //return NULL; // IC: Ignore error and continue building the mesh.
+        }
+
+        if (face != NULL) {
+            face->group = d->faceArray[f].group;
+            face->material = d->faceArray[f].material;
+        }
+    }
+
+    mesh->linkBoundary();
+
+    // We cannot fix functions here, because this would introduce new vertices and these vertices won't have the corresponding builder data.
+
+    // Maybe the builder should perform the search for T-junctions and update the vertex data directly.
+
+    // For now, we don't fix T-junctions at export time, but only during parameterization.
+
+    //mesh->fixBoundaryJunctions();
+
+    //mesh->sewBoundary();
+
+    return mesh.release();
+}
+
+
+bool MeshBuilder::buildPositions(Array<Vector3> & positionArray)
+{
+    const uint vertexCount = d->vertexArray.count();
+    positionArray.resize(vertexCount);
+
+    for (uint v = 0; v < vertexCount; v++)
+    {
+        nvDebugCheck(d->vertexArray[v].pos != NIL);
+        positionArray[v] = d->posArray[d->vertexArray[v].pos];
+    }
+
+    return true;
+}
+
+bool MeshBuilder::buildNormals(Array<Vector3> & normalArray)
+{
+    bool anyNormal = false;
+
+    const uint vertexCount = d->vertexArray.count();
+    normalArray.resize(vertexCount);
+
+    for (uint v = 0; v < vertexCount; v++)
+    {
+        if (d->vertexArray[v].nor == NIL) {
+            normalArray[v] = Vector3(0, 0, 1);
+        }
+        else {
+            anyNormal = true;
+            normalArray[v] = d->norArray[d->vertexArray[v].nor];
+        }
+    }
+
+    return anyNormal;
+}
+
+bool MeshBuilder::buildTexCoords(Array<Vector2> & texCoordArray, uint set/*=0*/)
+{
+    bool anyTexCoord = false;
+
+    const uint vertexCount = d->vertexArray.count();
+    texCoordArray.resize(vertexCount);
+
+    for (uint v = 0; v < vertexCount; v++)
+    {
+        if (d->vertexArray[v].tex[set] == NIL) {
+            texCoordArray[v] = Vector2(0, 0);
+        }
+        else {
+            anyTexCoord = true;
+            texCoordArray[v] = d->texArray[set][d->vertexArray[v].tex[set]];
+        }
+    }
+
+    return anyTexCoord;
+}
+
+bool MeshBuilder::buildColors(Array<Vector4> & colorArray, uint set/*=0*/)
+{
+    bool anyColor = false;
+
+    const uint vertexCount = d->vertexArray.count();
+    colorArray.resize(vertexCount);
+
+    for (uint v = 0; v < vertexCount; v++)
+    {
+        if (d->vertexArray[v].col[set] == NIL) {
+            colorArray[v] = Vector4(0, 0, 0, 1);
+        }
+        else {
+            anyColor = true;
+            colorArray[v] = d->colArray[set][d->vertexArray[v].col[set]];
+        }
+    }
+
+    return anyColor;
+}
+
+void MeshBuilder::buildVertexToPositionMap(Array<int> &map)
+{
+	const uint vertexCount = d->vertexArray.count();
+	map.resize(vertexCount);
+
+	foreach (i, d->vertexArray) {
+		map[i] = d->vertexArray[i].pos;
+	}
+}
+
+
+
+uint MeshBuilder::vertexCount() const
+{
+    return d->vertexArray.count();
+}
+
+
+uint MeshBuilder::positionCount() const
+{
+    return d->posArray.count();
+}
+
+uint MeshBuilder::normalCount() const
+{
+    return d->norArray.count();
+}
+
+uint MeshBuilder::texCoordCount(uint set/*=0*/) const
+{
+    return d->texArray[set].count();
+}
+
+uint MeshBuilder::colorCount(uint set/*=0*/) const
+{
+    return d->colArray[set].count();
+}
+
+
+uint MeshBuilder::materialCount() const
+{
+    return d->materialArray.count();
+}
+
+const char * MeshBuilder::material(uint i) const
+{
+    return d->materialArray[i].name;
+}
+
+
+uint MeshBuilder::positionIndex(uint vertex) const
+{
+    return d->vertexArray[vertex].pos;
+}
+uint MeshBuilder::normalIndex(uint vertex) const
+{
+    return d->vertexArray[vertex].nor;
+}
+uint MeshBuilder::texCoordIndex(uint vertex, uint set/*=0*/) const
+{
+    return d->vertexArray[vertex].tex[set];
+}
+uint MeshBuilder::colorIndex(uint vertex, uint set/*=0*/) const
+{
+    return d->vertexArray[vertex].col[set];
+}
diff --git a/thirdparty/thekla_atlas/nvmesh/MeshBuilder.h b/thirdparty/thekla_atlas/nvmesh/MeshBuilder.h
new file mode 100644
index 0000000000..5b3af3fc1d
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/MeshBuilder.h
@@ -0,0 +1,119 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#pragma once
+#ifndef NV_MESH_MESHBUILDER_H
+#define NV_MESH_MESHBUILDER_H
+
+#include "nvmesh.h"
+#include "nvcore/Array.h"
+#include "nvmath/Vector.h"
+
+namespace nv
+{
+    class String;
+    class TriMesh;
+    class QuadTriMesh;
+    namespace HalfEdge { class Mesh; }
+
+
+    /// Mesh builder is a helper class for importers.
+    /// Ideally it should handle any vertex data, but for now it only accepts positions, 
+    /// normals and texcoords.
+    class MeshBuilder
+    {
+        NV_FORBID_COPY(MeshBuilder);
+        NV_FORBID_HEAPALLOC();
+    public:
+        MeshBuilder();
+        ~MeshBuilder();
+
+        // Builder methods.
+        uint addPosition(const Vector3 & v);
+        uint addNormal(const Vector3 & v);
+        uint addTexCoord(const Vector2 & v, uint set = 0);
+        uint addColor(const Vector4 & v, uint set = 0);
+
+        void beginGroup(uint id);
+        void endGroup();
+
+        uint addMaterial(const char * name);
+        void beginMaterial(uint id);
+        void endMaterial();
+
+        void beginPolygon(uint id = 0);
+        uint addVertex(uint p, uint n = NIL, uint t0 = NIL, uint t1 = NIL, uint c0 = NIL, uint c1 = NIL, uint c2 = NIL);
+        uint addVertex(const Vector3 & p);
+        //uint addVertex(const Vector3 & p, const Vector3 & n, const Vector2 & t0 = Vector2(0), const Vector2 & t1 = Vector2(0), const Vector4 & c0 = Vector4(0), const Vector4 & c1 = Vector4(0));
+        bool endPolygon();
+
+        uint weldPositions();
+        uint weldNormals();
+        uint weldTexCoords(uint set = 0);
+        uint weldColors(uint set = 0);
+        void weldVertices();
+
+        void optimize(); // eliminate duplicate components and duplicate vertices.
+        void removeUnusedMaterials(Array<uint> & newMaterialId);
+        void sortFacesByGroup();
+        void sortFacesByMaterial();
+
+        void done();
+        void reset();
+
+        // Hints.
+        void hintTriangleCount(uint count);
+        void hintVertexCount(uint count);
+        void hintPositionCount(uint count);
+        void hintNormalCount(uint count);
+        void hintTexCoordCount(uint count, uint set = 0);
+        void hintColorCount(uint count, uint set = 0);
+
+        // Helpers.
+        void addTriangle(uint v0, uint v1, uint v2);
+        void addQuad(uint v0, uint v1, uint v2, uint v3);
+
+        // Get result.
+        TriMesh * buildTriMesh() const;
+        QuadTriMesh * buildQuadTriMesh() const;
+
+        enum Error {
+            Error_None,
+            Error_NonManifoldEdge,
+            Error_NonManifoldVertex,
+        };
+
+        HalfEdge::Mesh * buildHalfEdgeMesh(bool weldPositions, Error * error = NULL, Array<uint> * badFaces = NULL) const;
+
+        bool buildPositions(Array<Vector3> & positionArray);
+        bool buildNormals(Array<Vector3> & normalArray);
+        bool buildTexCoords(Array<Vector2> & texCoordArray, uint set = 0);
+        bool buildColors(Array<Vector4> & colorArray, uint set = 0);
+		void buildVertexToPositionMap(Array<int> & map);
+
+
+        // Expose attribute indices of the unified vertex array.
+        uint vertexCount() const;
+        
+        uint positionCount() const;
+        uint normalCount() const;
+        uint texCoordCount(uint set = 0) const;
+        uint colorCount(uint set = 0) const;
+
+        uint materialCount() const;
+        const char * material(uint i) const;
+
+        uint positionIndex(uint vertex) const;
+        uint normalIndex(uint vertex) const;
+        uint texCoordIndex(uint vertex, uint set = 0) const;
+        uint colorIndex(uint vertex, uint set = 0) const;
+
+    private:
+
+        struct PrivateData;
+        PrivateData * d;
+
+    };
+
+} // nv namespace
+
+#endif // NV_MESH_MESHBUILDER_H
diff --git a/thirdparty/thekla_atlas/nvmesh/MeshTopology.cpp b/thirdparty/thekla_atlas/nvmesh/MeshTopology.cpp
new file mode 100644
index 0000000000..e7e1dce421
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/MeshTopology.cpp
@@ -0,0 +1,122 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#include "nvmesh.h" // pch
+
+#include "nvcore/Array.h"
+#include "nvcore/BitArray.h"
+
+#include "nvmesh/MeshTopology.h"
+#include "nvmesh/halfedge/Mesh.h"
+#include "nvmesh/halfedge/Edge.h"
+#include "nvmesh/halfedge/Face.h"
+
+using namespace nv;
+
+void MeshTopology::buildTopologyInfo(const HalfEdge::Mesh * mesh)
+{
+    const uint vertexCount = mesh->colocalVertexCount();
+    const uint faceCount = mesh->faceCount();
+    const uint edgeCount = mesh->edgeCount();
+
+    nvDebug( "--- Building mesh topology:\n" );
+
+    Array<uint> stack(faceCount);
+
+    BitArray bitFlags(faceCount);
+    bitFlags.clearAll();
+
+    // Compute connectivity.
+    nvDebug( "---   Computing connectivity.\n" );
+
+    m_connectedCount = 0;
+
+    for(uint f = 0; f < faceCount; f++ ) {
+        if( bitFlags.bitAt(f) == false ) {
+            m_connectedCount++;
+
+            stack.pushBack( f );
+            while( !stack.isEmpty() ) {
+
+                const uint top = stack.back();
+                nvCheck(top != NIL);
+                stack.popBack();
+
+                if( bitFlags.bitAt(top) == false ) {
+                    bitFlags.setBitAt(top);
+
+                    const HalfEdge::Face * face = mesh->faceAt(top);
+                    const HalfEdge::Edge * firstEdge = face->edge;
+                    const HalfEdge::Edge * edge = firstEdge;
+
+                    do {
+                        const HalfEdge::Face * neighborFace = edge->pair->face;
+                        if (neighborFace != NULL) {
+                            stack.pushBack(neighborFace->id);
+                        }
+                        edge = edge->next;
+                    } while(edge != firstEdge);
+                }
+            }
+        }
+    }
+    nvCheck(stack.isEmpty());
+    nvDebug( "---   %d connected components.\n", m_connectedCount );
+
+
+    // Count boundary loops.
+    nvDebug( "---   Counting boundary loops.\n" );
+    m_boundaryCount = 0;
+
+    bitFlags.resize(edgeCount);
+    bitFlags.clearAll();
+
+    // Don't forget to link the boundary otherwise this won't work.
+    for (uint e = 0; e < edgeCount; e++)
+    {
+        const HalfEdge::Edge * startEdge = mesh->edgeAt(e);
+        if (startEdge != NULL && startEdge->isBoundary() && bitFlags.bitAt(e) == false)
+        {
+            nvDebugCheck(startEdge->face != NULL);
+            nvDebugCheck(startEdge->pair->face == NULL);
+
+            startEdge = startEdge->pair;
+
+            m_boundaryCount++;
+
+            const HalfEdge::Edge * edge = startEdge;
+            do {
+                bitFlags.setBitAt(edge->id / 2);
+                edge = edge->next;
+            } while(startEdge != edge);
+        }
+    }
+    nvDebug("---   %d boundary loops found.\n", m_boundaryCount );
+
+
+    // Compute euler number.
+    m_eulerNumber = vertexCount - edgeCount + faceCount;
+    nvDebug("---   Euler number: %d.\n", m_eulerNumber);
+
+
+    // Compute genus. (only valid on closed connected surfaces)
+    m_genus = -1;
+    if( isClosed() && isConnected() ) {
+        m_genus = (2 - m_eulerNumber) / 2;
+        nvDebug("---   Genus: %d.\n", m_genus);
+    }
+}
+
+
+/*static*/ bool MeshTopology::isQuadOnly(const HalfEdge::Mesh * mesh)
+{
+    const uint faceCount = mesh->faceCount();
+    for(uint f = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = mesh->faceAt(f);
+        if (face->edgeCount() != 4) {
+            return false;
+        }
+    }
+
+    return true;
+}
diff --git a/thirdparty/thekla_atlas/nvmesh/MeshTopology.h b/thirdparty/thekla_atlas/nvmesh/MeshTopology.h
new file mode 100644
index 0000000000..c3d7477b15
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/MeshTopology.h
@@ -0,0 +1,66 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#pragma once
+#ifndef NV_MESH_MESHTOPOLOGY_H
+#define NV_MESH_MESHTOPOLOGY_H
+
+#include <nvmesh/nvmesh.h>
+
+namespace nv
+{
+    namespace HalfEdge { class Mesh; }
+    class MeshAdjacency;
+
+    /// Mesh topology information.
+    class MeshTopology
+    {
+    public:
+        MeshTopology(const HalfEdge::Mesh * mesh) { buildTopologyInfo(mesh); }
+
+        /// Determine if the mesh is connected.
+        bool isConnected() const { return m_connectedCount == 1; }
+
+        /// Determine if the mesh is closed. (Each edge is shared by two faces)
+        bool isClosed() const { return m_boundaryCount == 0; }
+
+        /// Return true if the mesh has the topology of a disk.
+        bool isDisk() const { return isConnected() && m_boundaryCount == 1/* && m_eulerNumber == 1*/; }
+
+        /// Return the number of connected components.
+        int connectedCount() const { return m_connectedCount; }
+
+        /// Return the number of open holes.
+        int holeCount() const { return m_boundaryCount; }
+
+        /// Return the genus of the mesh.
+        int genus() const { return m_genus; }
+
+        /// Return the euler number of the mesh.
+        int euler() const { return m_eulerNumber; }
+
+
+        static bool isQuadOnly(const HalfEdge::Mesh * mesh);
+
+
+    private:
+
+        NVMESH_API void buildTopologyInfo(const HalfEdge::Mesh * mesh);
+
+    private:
+
+        ///< Number of boundary loops.
+        int m_boundaryCount;		
+
+        ///< Number of connected components.
+        int m_connectedCount;		
+
+        ///< Euler number.
+        int m_eulerNumber;
+
+        /// Mesh genus.
+        int m_genus;
+    };
+
+} // nv namespace
+
+#endif // NV_MESH_MESHTOPOLOGY_H
diff --git a/thirdparty/thekla_atlas/nvmesh/QuadTriMesh.cpp b/thirdparty/thekla_atlas/nvmesh/QuadTriMesh.cpp
new file mode 100644
index 0000000000..64a071abe9
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/QuadTriMesh.cpp
@@ -0,0 +1,36 @@
+// This code is in the public domain -- Ignacio Castaņo <castano@gmail.com>
+
+#include "QuadTriMesh.h"
+#include "Stream.h"
+
+using namespace nv;
+
+
+bool QuadTriMesh::isQuadFace(uint i) const 
+{ 
+    return m_faceArray[i].isQuadFace();
+}
+
+const QuadTriMesh::Vertex & QuadTriMesh::faceVertex(uint f, uint v) const 
+{
+    if (isQuadFace(f)) nvDebugCheck(v < 4);
+    else nvDebugCheck(v < 3);
+
+    const Face & face = this->faceAt(f);
+    return this->vertexAt(face.v[v]);
+}
+
+
+namespace nv
+{
+    static Stream & operator<< (Stream & s, QuadTriMesh::Face & face)
+    {
+        return s << face.id << face.v[0] << face.v[1] << face.v[2] << face.v[3];
+    }
+
+    Stream & operator<< (Stream & s, QuadTriMesh & mesh)
+    {
+        return s << mesh.m_faceArray << (BaseMesh &) mesh;
+    }
+}
+
diff --git a/thirdparty/thekla_atlas/nvmesh/QuadTriMesh.h b/thirdparty/thekla_atlas/nvmesh/QuadTriMesh.h
new file mode 100644
index 0000000000..b8465f2db0
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/QuadTriMesh.h
@@ -0,0 +1,60 @@
+// This code is in the public domain -- Ignacio Castaņo <castano@gmail.com>
+
+#pragma once
+#ifndef NV_MESH_QUADTRIMESH_H
+#define NV_MESH_QUADTRIMESH_H
+
+#include "nvcore/Array.h"
+#include "nvmath/Vector.h"
+#include "nvmesh/nvmesh.h"
+#include "nvmesh/BaseMesh.h"
+
+namespace nv
+{
+    class Stream;
+
+    /// Mixed quad/triangle mesh.
+    class QuadTriMesh : public BaseMesh
+    {
+    public:
+        struct Face;
+        typedef BaseMesh::Vertex Vertex;
+
+        QuadTriMesh() {};
+        QuadTriMesh(uint faceCount, uint vertexCount) : BaseMesh(vertexCount), m_faceArray(faceCount) {}
+
+        // Face methods.
+        uint faceCount() const { return m_faceArray.count(); }
+
+        const Face & faceAt(uint i) const { return m_faceArray[i]; }
+        Face & faceAt(uint i) { return m_faceArray[i]; }
+
+        const Array<Face> & faces() const { return m_faceArray; }
+        Array<Face> & faces() { return m_faceArray; }
+
+        bool isQuadFace(uint i) const;
+
+        const Vertex & faceVertex(uint f, uint v) const;
+
+        friend Stream & operator<< (Stream & s, QuadTriMesh & obj);
+
+    private:
+
+        Array<Face> m_faceArray;
+
+    };
+
+
+    /// QuadTriMesh face.
+    struct QuadTriMesh::Face
+    {
+        uint id;
+        uint v[4];
+
+        bool isQuadFace() const { return v[3] != NIL; }
+    };
+
+} // nv namespace
+
+
+#endif // NV_MESH_QUADTRIMESH_H
diff --git a/thirdparty/thekla_atlas/nvmesh/TriMesh.cpp b/thirdparty/thekla_atlas/nvmesh/TriMesh.cpp
new file mode 100644
index 0000000000..bf10a474fb
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/TriMesh.cpp
@@ -0,0 +1,25 @@
+// This code is in the public domain -- Ignacio Castaņo <castano@gmail.com>
+
+#include "TriMesh.h"
+
+using namespace nv;
+
+
+/// Triangle mesh.
+Vector3 TriMesh::faceNormal(uint f) const
+{
+    const Face & face = this->faceAt(f);
+    const Vector3 & p0 = this->vertexAt(face.v[0]).pos;
+    const Vector3 & p1 = this->vertexAt(face.v[1]).pos;
+    const Vector3 & p2 = this->vertexAt(face.v[2]).pos;
+    return normalizeSafe(cross(p1 - p0, p2 - p0), Vector3(0.0f), 0.0f);
+}
+
+/// Get face vertex.
+const TriMesh::Vertex & TriMesh::faceVertex(uint f, uint v) const
+{
+    nvDebugCheck(v < 3);
+    const Face & face = this->faceAt(f);
+    return this->vertexAt(face.v[v]);
+}
+
diff --git a/thirdparty/thekla_atlas/nvmesh/TriMesh.h b/thirdparty/thekla_atlas/nvmesh/TriMesh.h
new file mode 100644
index 0000000000..bc5672c1ac
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/TriMesh.h
@@ -0,0 +1,51 @@
+// This code is in the public domain -- Ignacio Castaņo <castano@gmail.com>
+
+#pragma once
+#ifndef NV_MESH_TRIMESH_H
+#define NV_MESH_TRIMESH_H
+
+#include "nvcore/Array.h"
+#include "nvmath/Vector.inl"
+#include "nvmesh/nvmesh.h"
+#include "nvmesh/BaseMesh.h"
+
+namespace nv
+{
+    /// Triangle mesh.
+    class TriMesh : public BaseMesh
+    {
+    public:
+        struct Face;
+        typedef BaseMesh::Vertex Vertex;
+
+        TriMesh(uint faceCount, uint vertexCount) : BaseMesh(vertexCount), m_faceArray(faceCount) {}
+
+        // Face methods.
+        uint faceCount() const { return m_faceArray.count(); }
+        const Face & faceAt(uint i) const { return m_faceArray[i]; }
+        Face & faceAt(uint i) { return m_faceArray[i]; }
+        const Array<Face> & faces() const { return m_faceArray; }
+        Array<Face> & faces() { return m_faceArray; }
+
+        NVMESH_API Vector3 faceNormal(uint f) const;
+        NVMESH_API const Vertex & faceVertex(uint f, uint v) const;
+
+        friend Stream & operator<< (Stream & s, BaseMesh & obj);
+
+    private:
+
+        Array<Face> m_faceArray;
+
+    };
+
+
+    /// TriMesh face.
+    struct TriMesh::Face
+    {
+        uint id;
+        uint v[3];
+    };
+
+} // nv namespace
+
+#endif // NV_MESH_TRIMESH_H
diff --git a/thirdparty/thekla_atlas/nvmesh/geometry/Bounds.cpp b/thirdparty/thekla_atlas/nvmesh/geometry/Bounds.cpp
new file mode 100644
index 0000000000..69fd1deb24
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/geometry/Bounds.cpp
@@ -0,0 +1,54 @@
+// This code is in the public domain -- Ignacio CastaÃąo <castano@gmail.com>
+
+#include "nvmesh.h" // pch
+
+#include "Bounds.h"
+
+#include "nvmesh/BaseMesh.h"
+#include "nvmesh/halfedge/Mesh.h"
+#include "nvmesh/halfedge/Vertex.h"
+
+#include "nvmath/Box.inl"
+
+using namespace nv;
+
+Box MeshBounds::box(const BaseMesh * mesh)
+{
+    nvCheck(mesh != NULL);
+
+    Box bounds;
+    bounds.clearBounds();
+
+    const uint vertexCount = mesh->vertexCount();
+    for (uint v = 0; v < vertexCount; v++)
+    {
+        const BaseMesh::Vertex & vertex = mesh->vertexAt(v);
+        bounds.addPointToBounds( vertex.pos );
+    }
+
+    return bounds;
+}
+
+Box MeshBounds::box(const HalfEdge::Mesh * mesh)
+{
+    nvCheck(mesh != NULL);
+
+    Box bounds;
+    bounds.clearBounds();
+
+    const uint vertexCount = mesh->vertexCount();
+    for (uint v = 0; v < vertexCount; v++)
+    {
+        const HalfEdge::Vertex * vertex = mesh->vertexAt(v);
+        nvDebugCheck(vertex != NULL);
+        bounds.addPointToBounds( vertex->pos );
+    }
+
+    return bounds;
+}
+
+/*Sphere MeshBounds::sphere(const HalfEdge::Mesh * mesh)
+{
+    // @@ TODO
+    return Sphere();
+}*/
diff --git a/thirdparty/thekla_atlas/nvmesh/geometry/Bounds.h b/thirdparty/thekla_atlas/nvmesh/geometry/Bounds.h
new file mode 100644
index 0000000000..1cb5b7b905
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/geometry/Bounds.h
@@ -0,0 +1,28 @@
+// This code is in the public domain -- Ignacio CastaÃąo <castano@gmail.com>
+
+#pragma once
+#ifndef NV_MESH_MESHBOUNDS_H
+#define NV_MESH_MESHBOUNDS_H
+
+#include <nvmath/Sphere.h>
+#include <nvmath/Box.h>
+
+#include <nvmesh/nvmesh.h>
+
+namespace nv
+{
+    class BaseMesh;
+    namespace HalfEdge { class Mesh; }
+
+    // Bounding volumes computation.
+    namespace MeshBounds
+    {
+        Box box(const BaseMesh * mesh);
+        Box box(const HalfEdge::Mesh * mesh);
+
+        Sphere sphere(const HalfEdge::Mesh * mesh);
+    }
+
+} // nv namespace
+
+#endif // NV_MESH_MESHBOUNDS_H
diff --git a/thirdparty/thekla_atlas/nvmesh/geometry/Measurements.cpp b/thirdparty/thekla_atlas/nvmesh/geometry/Measurements.cpp
new file mode 100644
index 0000000000..e0c271663b
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/geometry/Measurements.cpp
@@ -0,0 +1,36 @@
+// This code is in the public domain -- castano@gmail.com
+
+#include "nvmesh.h" // pch
+
+#include "Measurements.h"
+#include "nvmesh/halfedge/Mesh.h"
+#include "nvmesh/halfedge/Face.h"
+
+using namespace nv;
+
+float nv::computeSurfaceArea(const HalfEdge::Mesh * mesh)
+{
+    float area = 0;
+
+    for (HalfEdge::Mesh::ConstFaceIterator it(mesh->faces()); !it.isDone(); it.advance())
+    {
+        const HalfEdge::Face * face = it.current();
+        area += face->area();
+    }
+    nvDebugCheck(area >= 0);
+
+    return area;
+}
+
+float nv::computeParametricArea(const HalfEdge::Mesh * mesh)
+{
+    float area = 0;
+
+    for (HalfEdge::Mesh::ConstFaceIterator it(mesh->faces()); !it.isDone(); it.advance())
+    {
+        const HalfEdge::Face * face = it.current();
+        area += face->parametricArea();
+    }
+
+    return area;
+}
diff --git a/thirdparty/thekla_atlas/nvmesh/geometry/Measurements.h b/thirdparty/thekla_atlas/nvmesh/geometry/Measurements.h
new file mode 100644
index 0000000000..0be863b79e
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/geometry/Measurements.h
@@ -0,0 +1,18 @@
+// This code is in the public domain -- castano@gmail.com
+
+#pragma once
+#ifndef NV_MESH_MESHMEASUREMENTS_H
+#define NV_MESH_MESHMEASUREMENTS_H
+
+#include "nvmesh/nvmesh.h"
+
+namespace nv
+{
+    namespace HalfEdge { class Mesh; }
+
+	float computeSurfaceArea(const HalfEdge::Mesh * mesh);
+	float computeParametricArea(const HalfEdge::Mesh * mesh);
+
+} // nv namespace
+
+#endif // NV_MESH_MESHMEASUREMENTS_H
diff --git a/thirdparty/thekla_atlas/nvmesh/halfedge/Edge.cpp b/thirdparty/thekla_atlas/nvmesh/halfedge/Edge.cpp
new file mode 100644
index 0000000000..671650296c
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/halfedge/Edge.cpp
@@ -0,0 +1,57 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#include "nvmesh.h" // pch
+
+#include "Edge.h"
+#include "Vertex.h"
+
+#include "nvmath/Vector.inl"
+
+using namespace nv;
+using namespace HalfEdge;
+
+Vector3 Edge::midPoint() const
+{
+    return (to()->pos + from()->pos) * 0.5f;
+}
+
+float Edge::length() const
+{
+    return ::length(to()->pos - from()->pos); 
+}
+
+// Return angle between this edge and the previous one.
+float Edge::angle() const {
+    Vector3 p = vertex->pos;
+    Vector3 a = prev->vertex->pos;
+    Vector3 b = next->vertex->pos;
+
+    Vector3 v0 = a - p;
+    Vector3 v1 = b - p;
+
+    return acosf(dot(v0, v1) / (nv::length(v0) * nv::length(v1)));
+}
+
+bool Edge::isValid() const
+{
+    // null face is OK.
+    if (next == NULL || prev == NULL || pair == NULL || vertex == NULL) return false;
+    if (next->prev != this) return false;
+    if (prev->next != this) return false;
+    if (pair->pair != this) return false;
+    return true;
+}
+
+/*
+Edge * Edge::nextBoundary() {
+    nvDebugCheck(this->m_pair == NULL);
+
+}
+
+Edge * Edge::prevBoundary() {
+    nvDebugCheck(this->m_pair == NULL);
+
+}
+*/
+
+
diff --git a/thirdparty/thekla_atlas/nvmesh/halfedge/Edge.h b/thirdparty/thekla_atlas/nvmesh/halfedge/Edge.h
new file mode 100644
index 0000000000..25c47f4860
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/halfedge/Edge.h
@@ -0,0 +1,70 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#pragma once
+#ifndef NV_MESH_HALFEDGE_EDGE_H
+#define NV_MESH_HALFEDGE_EDGE_H
+
+#include "nvmath/Vector.h"
+
+namespace nv
+{
+    namespace HalfEdge { class Vertex; class Face; class Edge; }
+
+    /// Half edge edge. 
+    class HalfEdge::Edge
+    {
+        NV_FORBID_COPY(Edge);
+    public:
+
+        uint id;
+
+        Edge * next;
+        Edge * prev;	// This is not strictly half-edge, but makes algorithms easier and faster.
+        Edge * pair;
+        Vertex * vertex;
+        Face * face;
+
+
+        // Default constructor.
+        Edge(uint id) : id(id), next(NULL), prev(NULL), pair(NULL), vertex(NULL), face(NULL)
+        {
+        }
+
+
+        // Vertex queries.
+        const Vertex * from() const { return vertex; }
+        Vertex * from() { return vertex; }
+
+        const Vertex * to() const { return pair->vertex; }  // This used to be 'next->vertex', but that changed often when the connectivity of the mesh changes.
+        Vertex * to() { return pair->vertex; }
+
+
+        // Edge queries.
+        void setNext(Edge * e) { next = e; if (e != NULL) e->prev = this; }
+        void setPrev(Edge * e) { prev = e; if (e != NULL) e->next = this; }
+
+        // @@ Add these helpers:
+        //Edge * nextBoundary();
+        //Edge * prevBoundary();
+
+
+        // @@ It would be more simple to only check m_pair == NULL
+        // Face queries.
+        bool isBoundary() const { return !(face && pair->face); }
+
+        // @@ This is not exactly accurate, we should compare the texture coordinates...
+        bool isSeam() const { return vertex != pair->next->vertex || next->vertex != pair->vertex; }
+
+        bool isValid() const;
+
+        // Geometric queries.
+        Vector3 midPoint() const;
+        float length() const;
+        float angle() const;
+
+    };
+
+} // nv namespace
+
+
+#endif // NV_MESH_HALFEDGE_EDGE_H
diff --git a/thirdparty/thekla_atlas/nvmesh/halfedge/Face.cpp b/thirdparty/thekla_atlas/nvmesh/halfedge/Face.cpp
new file mode 100644
index 0000000000..9f6987154e
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/halfedge/Face.cpp
@@ -0,0 +1,268 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#include "nvmesh.h" // pch
+
+#include "Face.h"
+#include "Vertex.h"
+
+#include "nvmath/Fitting.h"
+#include "nvmath/Plane.h"
+#include "nvmath/Vector.inl"
+
+#include "nvcore/Array.h"
+
+
+using namespace nv;
+using namespace HalfEdge;
+
+/// Get face area.
+float Face::area() const
+{
+    float area = 0;
+    const Vector3 & v0 = edge->from()->pos;
+
+    for (ConstEdgeIterator it(edges(edge->next)); it.current() != edge->prev; it.advance())
+    {
+        const Edge * e = it.current();
+
+        const Vector3 & v1 = e->vertex->pos;
+        const Vector3 & v2 = e->next->vertex->pos; 
+
+        area += length(cross(v1-v0, v2-v0));
+    }
+
+    return area * 0.5f;
+}
+
+float Face::parametricArea() const
+{
+    float area = 0;
+    const Vector2 & v0 = edge->from()->tex;
+
+    for (ConstEdgeIterator it(edges(edge->next)); it.current() != edge->prev; it.advance())
+    {
+        const Edge * e = it.current();
+
+        const Vector2 & v1 = e->vertex->tex;
+        const Vector2 & v2 = e->next->vertex->tex;
+
+        area += triangleArea(v0, v1, v2);
+    }
+
+    return area * 0.5f;
+}
+
+
+/// Get boundary length.
+float Face::boundaryLength() const
+{
+    float bl = 0;
+
+    for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
+    {
+        const Edge * edge = it.current();
+        bl += edge->length();
+    }
+
+    return bl;
+}
+
+
+/// Get face normal.
+Vector3 Face::normal() const
+{
+    Vector3 n(0);
+
+    const Vertex * vertex0 = NULL;
+
+    for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
+    {
+        const Edge * edge = it.current();
+        nvCheck(edge != NULL);
+
+        if (vertex0 == NULL)
+        {
+            vertex0 = edge->vertex;
+        }
+        else if (edge->next->vertex != vertex0)
+        {
+            const HalfEdge::Vertex * vertex1 = edge->from();
+            const HalfEdge::Vertex * vertex2 = edge->to();
+
+            const Vector3 & p0 = vertex0->pos;
+            const Vector3 & p1 = vertex1->pos;
+            const Vector3 & p2 = vertex2->pos;
+
+            Vector3 v10 = p1 - p0;
+            Vector3 v20 = p2 - p0;
+
+            n += cross(v10, v20);
+        }
+    }
+
+    return normalizeSafe(n, Vector3(0, 0, 1), 0.0f);
+
+
+    // Get face points eliminating duplicates.
+    /*Array<Vector3> points(4);
+
+    points.append(m_edge->prev()->from()->pos);
+
+    for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
+    {
+        const Edge * edge = it.current();
+        nvDebugCheck(edge != NULL);
+
+        const Vector3 & p = edge->from()->pos;
+        if (points.back() != p)
+        {
+            points.append(edge->from()->pos);
+        }
+    }
+
+    points.popBack();
+
+    if (points.count() < 3)
+    {
+        // Invalid normal.
+        return Vector3(0.0f);
+    }
+    else
+    {
+        // Compute regular normal.
+        Vector3 normal = normalizeSafe(cross(points[1] - points[0], points[2] - points[0]), Vector3(0.0f), 0.0f);
+
+#pragma NV_MESSAGE("TODO: make sure these three points are not colinear")
+
+        if (points.count() > 3)
+        {
+            // Compute best fitting plane to the points.
+            Plane plane = Fit::bestPlane(points.count(), points.buffer());
+
+            // Adjust normal orientation.
+            if (dot(normal, plane.vector()) > 0) {
+                normal = plane.vector();
+            }
+            else {
+                normal = -plane.vector();
+            }
+        }
+
+        nvDebugCheck(isNormalized(normal));
+        return normal;
+    }*/
+}
+
+Vector3 Face::centroid() const
+{
+    Vector3 sum(0.0f);
+    uint count = 0;
+
+    for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
+    {
+        const Edge * edge = it.current();
+        sum += edge->from()->pos;
+        count++;
+    }
+
+    return sum / float(count);
+}
+
+
+bool Face::isValid() const
+{
+    uint count = 0;
+
+    for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
+    {
+        const Edge * edge = it.current();
+        if (edge->face != this) return false;
+        if (!edge->isValid()) return false;
+        if (!edge->pair->isValid()) return false;
+        count++;
+    }
+
+    if (count < 3) return false;
+
+    return true;
+}
+
+
+// Determine if this face contains the given edge.
+bool Face::contains(const Edge * e) const
+{
+    for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
+    {
+        if(it.current() == e) return true;
+    }
+    return false;
+}
+
+// Returns index in this face of the given edge.
+uint Face::edgeIndex(const Edge * e) const
+{
+    int i = 0;
+    for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance(), i++)
+    {
+        if(it.current() == e) return i;
+    }
+    return NIL;
+}
+
+
+Edge * Face::edgeAt(uint idx)
+{ 
+    int i = 0;
+    for(EdgeIterator it(edges()); !it.isDone(); it.advance(), i++) {
+        if (i == idx) return it.current();
+    }
+    return NULL;
+}
+const Edge * Face::edgeAt(uint idx) const 
+{
+    int i = 0;
+    for(ConstEdgeIterator it(edges()); !it.isDone(); it.advance(), i++) {
+        if (i == idx) return it.current();
+    }
+    return NULL;
+}
+
+
+// Count the number of edges in this face.
+uint Face::edgeCount() const
+{
+    uint count = 0;
+    for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance()) { ++count; }
+    return count;
+}
+
+// Determine if this is a boundary face.
+bool Face::isBoundary() const
+{
+    for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
+    {
+        const Edge * edge = it.current();
+        nvDebugCheck(edge->pair != NULL);
+
+        if (edge->pair->face == NULL) {
+            return true;
+        }
+    }
+    return false;
+}
+
+// Count the number of boundary edges in the face.
+uint Face::boundaryCount() const
+{
+    uint count = 0;
+    for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance())
+    {
+        const Edge * edge = it.current();
+        nvDebugCheck(edge->pair != NULL);
+
+        if (edge->pair->face == NULL) {
+            count++;
+        }
+    }
+    return count;
+}
diff --git a/thirdparty/thekla_atlas/nvmesh/halfedge/Face.h b/thirdparty/thekla_atlas/nvmesh/halfedge/Face.h
new file mode 100644
index 0000000000..677f8666f0
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/halfedge/Face.h
@@ -0,0 +1,106 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#pragma once
+#ifndef NV_MESH_HALFEDGE_FACE_H
+#define NV_MESH_HALFEDGE_FACE_H
+
+#include <nvmesh/halfedge/Edge.h>
+
+namespace nv
+{
+    namespace HalfEdge { class Vertex; class Face; class Edge; }
+
+    /// Face of a half-edge mesh.
+    class HalfEdge::Face
+    {
+        NV_FORBID_COPY(Face);
+    public:
+
+        uint id;
+        uint16 group;
+        uint16 material;
+        Edge * edge;
+
+
+        Face(uint id) : id(id), group(~0), material(~0), edge(NULL) {}
+
+        float area() const;
+        float parametricArea() const;
+        float boundaryLength() const;
+        Vector3 normal() const;
+        Vector3 centroid() const;
+
+        bool isValid() const;
+
+        bool contains(const Edge * e) const;
+        uint edgeIndex(const Edge * e) const;
+        
+        Edge * edgeAt(uint idx);
+        const Edge * edgeAt(uint idx) const;
+
+        uint edgeCount() const;
+        bool isBoundary() const;
+        uint boundaryCount() const;
+
+
+        // The iterator that visits the edges of this face in clockwise order.
+        class EdgeIterator //: public Iterator<Edge *>
+        {
+        public:
+            EdgeIterator(Edge * e) : m_end(NULL), m_current(e) { }
+
+            virtual void advance()
+            {
+                if (m_end == NULL) m_end = m_current;
+                m_current = m_current->next;
+            }
+
+            virtual bool isDone() const { return m_end == m_current; }
+            virtual Edge * current() const { return m_current; }
+            Vertex * vertex() const { return m_current->vertex; }
+
+        private:
+            Edge * m_end;
+            Edge * m_current;
+        };
+
+        EdgeIterator edges() { return EdgeIterator(edge); }
+        EdgeIterator edges(Edge * e)
+        { 
+            nvDebugCheck(contains(e));
+            return EdgeIterator(e); 
+        }
+
+        // The iterator that visits the edges of this face in clockwise order.
+        class ConstEdgeIterator //: public Iterator<const Edge *>
+        {
+        public:
+            ConstEdgeIterator(const Edge * e) : m_end(NULL), m_current(e) { }
+            ConstEdgeIterator(const EdgeIterator & it) : m_end(NULL), m_current(it.current()) { }
+
+            virtual void advance()
+            {
+                if (m_end == NULL) m_end = m_current;
+                m_current = m_current->next;
+            }
+
+            virtual bool isDone() const { return m_end == m_current; }
+            virtual const Edge * current() const { return m_current; }
+            const Vertex * vertex() const { return m_current->vertex; }
+
+        private:
+            const Edge * m_end;
+            const Edge * m_current;
+        };
+
+        ConstEdgeIterator edges() const { return ConstEdgeIterator(edge); }
+        ConstEdgeIterator edges(const Edge * e) const
+        { 
+            nvDebugCheck(contains(e));
+            return ConstEdgeIterator(e); 
+        }
+    };
+
+} // nv namespace
+
+#endif // NV_MESH_HALFEDGE_FACE_H
diff --git a/thirdparty/thekla_atlas/nvmesh/halfedge/Mesh.cpp b/thirdparty/thekla_atlas/nvmesh/halfedge/Mesh.cpp
new file mode 100644
index 0000000000..0012513bce
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/halfedge/Mesh.cpp
@@ -0,0 +1,1284 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#include "nvmesh.h" // pch
+
+#include "Mesh.h"
+#include "Edge.h"
+#include "Vertex.h"
+#include "Face.h"
+
+#include "nvmesh/TriMesh.h"
+#include "nvmesh/QuadTriMesh.h"
+#include "nvmesh/MeshBuilder.h"
+
+#include "nvmath/Vector.inl"
+#include "nvcore/Array.inl"
+#include "nvcore/HashMap.inl"
+
+
+using namespace nv;
+using namespace HalfEdge;
+
+Mesh::Mesh() : m_colocalVertexCount(0)
+{
+    errorCount = 0;
+}
+
+Mesh::Mesh(const Mesh * mesh)
+{
+    errorCount = 0;
+
+    // Copy mesh vertices.
+    const uint vertexCount = mesh->vertexCount();
+    m_vertexArray.resize(vertexCount);
+
+    for (uint v = 0; v < vertexCount; v++)
+    {
+        const Vertex * vertex = mesh->vertexAt(v);
+        nvDebugCheck(vertex->id == v);
+
+        m_vertexArray[v] = new Vertex(v);
+        m_vertexArray[v]->pos = vertex->pos;
+        m_vertexArray[v]->nor = vertex->nor;
+        m_vertexArray[v]->tex = vertex->tex;
+    }
+
+    m_colocalVertexCount = vertexCount;
+
+
+    // Copy mesh faces.
+    const uint faceCount = mesh->faceCount();
+
+    Array<uint> indexArray(3);
+
+    for (uint f = 0; f < faceCount; f++)
+    {
+        const Face * face = mesh->faceAt(f);
+
+        for(Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance()) {
+            const Vertex * vertex = it.current()->from();
+            indexArray.append(vertex->id);
+        }
+
+        addFace(indexArray);
+        indexArray.clear();
+    }
+}
+
+Mesh::~Mesh()
+{
+    clear();
+}
+
+
+void Mesh::clear()
+{
+    deleteAll(m_vertexArray); 
+    m_vertexArray.clear();
+
+    foreach(i, m_edgeMap)
+    {
+        delete m_edgeMap[i].value;
+    }
+    //deleteAll(m_edgeArray);	// edgeArray only contains 1/2 of the edges!
+    m_edgeArray.clear();
+    m_edgeMap.clear();
+
+    deleteAll(m_faceArray);
+    m_faceArray.clear();
+}
+
+
+Vertex * Mesh::addVertex(const Vector3 & pos)
+{
+    nvDebugCheck(isFinite(pos));
+
+    Vertex * v = new Vertex(m_vertexArray.count());
+    v->pos = pos;
+    m_vertexArray.append(v);
+
+    return v;
+
+//    return addVertex(m_vertexArray.count(), pos);
+}
+
+/*Vertex * Mesh::addVertex(uint id, const Vector3 & pos)
+{
+    nvDebugCheck(isFinite(pos));
+
+    Vertex * v = new Vertex(id);
+    v->pos = pos;
+    m_vertexArray.append(v);
+
+    return v;
+}*/
+
+/*void Mesh::addVertices(const Mesh * mesh)
+{
+nvCheck(mesh != NULL);
+
+// Add mesh vertices
+for (uint v = 0; v < vertexCount; v++)
+{
+const Vertex * vertex = mesh->vertexAt(v);
+nvDebugCheck(vertex != NULL);
+
+Vertex * v = addVertex(vertex->pos());
+nvDebugCheck(v != NULL);
+
+v->setNor(vertex->nor());
+v->setTex(vertex->tex());
+}
+}*/
+
+
+/// Link colocal vertices based on geometric location only.
+void Mesh::linkColocals()
+{
+    nvDebug("--- Linking colocals:\n");
+
+    const uint vertexCount = this->vertexCount();
+    HashMap<Vector3, Vertex *> vertexMap(vertexCount);
+
+    for (uint v = 0; v < vertexCount; v++)
+    {
+        Vertex * vertex = vertexAt(v);
+
+        Vertex * colocal;
+        if (vertexMap.get(vertex->pos, &colocal))
+        {
+            colocal->linkColocal(vertex);
+        }
+        else
+        {
+            vertexMap.add(vertex->pos, vertex);
+        }
+    }
+
+    m_colocalVertexCount = vertexMap.count();
+
+    nvDebug("---   %d vertex positions.\n", m_colocalVertexCount);
+
+    // @@ Remove duplicated vertices? or just leave them as colocals?
+}
+
+void Mesh::linkColocalsWithCanonicalMap(const Array<uint> & canonicalMap)
+{
+    nvDebug("--- Linking colocals:\n");
+
+    uint vertexMapSize = 0;
+    foreach(i, canonicalMap) {
+        vertexMapSize = max(vertexMapSize, canonicalMap[i] + 1);
+    }
+    
+    Array<Vertex *> vertexMap;
+    vertexMap.resize(vertexMapSize, NULL);
+
+    m_colocalVertexCount = 0;
+
+    const uint vertexCount = this->vertexCount();
+    for (uint v = 0; v < vertexCount; v++)
+    {
+        Vertex * vertex = vertexAt(v);
+
+        Vertex * colocal = vertexMap[canonicalMap[v]];
+        if (colocal != NULL)
+        {
+            nvDebugCheck(vertex->pos == colocal->pos);
+            colocal->linkColocal(vertex);
+        }
+        else
+        {
+            vertexMap[canonicalMap[v]] = vertex;
+            m_colocalVertexCount++;
+        }
+    }
+
+    nvDebug("---   %d vertex positions.\n", m_colocalVertexCount);
+}
+
+
+Face * Mesh::addFace()
+{
+    Face * f = new Face(m_faceArray.count());
+    m_faceArray.append(f);
+    return f;
+}
+
+Face * Mesh::addFace(uint v0, uint v1, uint v2)
+{
+    Array<uint> indexArray(3);
+    indexArray << v0 << v1 << v2;
+    return addFace(indexArray, 0, 3);
+}
+
+Face * Mesh::addFace(uint v0, uint v1, uint v2, uint v3)
+{
+    Array<uint> indexArray(4);
+    indexArray << v0 << v1 << v2 << v3;
+    return addFace(indexArray, 0, 4);
+}
+
+Face * Mesh::addFace(const Array<uint> & indexArray)
+{
+    return addFace(indexArray, 0, indexArray.count());
+}
+
+
+Face * Mesh::addFace(const Array<uint> & indexArray, uint first, uint num)
+{
+    nvDebugCheck(first < indexArray.count());
+    nvDebugCheck(num <= indexArray.count()-first);
+    nvDebugCheck(num > 2);
+
+    if (!canAddFace(indexArray, first, num)) {
+        errorCount++;
+        return NULL;
+    }
+
+    Face * f = new Face(m_faceArray.count());
+
+    Edge * firstEdge = NULL;
+    Edge * last = NULL;
+    Edge * current = NULL;
+
+    for(uint i = 0; i < num-1; i++)
+    {
+        current = addEdge(indexArray[first+i], indexArray[first+i+1]);
+        nvCheck(current != NULL && current->face == NULL);
+
+        current->face = f;
+
+        if (last != NULL) last->setNext(current);
+        else firstEdge = current;
+
+        last = current;
+    }
+
+    current = addEdge(indexArray[first+num-1], indexArray[first]);
+    nvCheck(current != NULL && current->face == NULL);
+
+    current->face = f;
+
+    last->setNext(current);
+    current->setNext(firstEdge);
+
+    f->edge = firstEdge;
+    m_faceArray.append(f);
+
+    return f;
+}
+
+/*void Mesh::addFaces(const Mesh * mesh)
+{
+nvCheck(mesh != NULL);
+
+Array indexArray;
+// Add faces
+
+}*/
+
+
+// Return true if the face can be added to the manifold mesh.
+bool Mesh::canAddFace(const Array<uint> & indexArray, uint first, uint num) const
+{
+    for (uint j = num - 1, i = 0; i < num; j = i++) {
+        if (!canAddEdge(indexArray[first+j], indexArray[first+i])) {
+            errorIndex0 = indexArray[first+j];
+            errorIndex1 = indexArray[first+i];
+            return false;
+        }
+    }
+
+    // We also have to make sure the face does not have any duplicate edge!
+    for (uint i = 0; i < num; i++) {
+
+        int i0 = indexArray[first + i + 0];
+        int i1 = indexArray[first + (i + 1)%num];
+
+        for (uint j = i + 1; j < num; j++) {
+            int j0 = indexArray[first + j + 0];
+            int j1 = indexArray[first + (j + 1)%num];
+
+            if (i0 == j0 && i1 == j1) {
+                return false;
+            }
+        }
+    }
+
+    return true;
+}
+
+// Return true if the edge doesn't exist or doesn't have any adjacent face. 
+bool Mesh::canAddEdge(uint i, uint j) const
+{
+    if (i == j) {
+        // Skip degenerate edges.
+        return false;
+    }
+
+    // Same check, but taking into account colocal vertices.
+    const Vertex * v0 = vertexAt(i);
+    const Vertex * v1 = vertexAt(j);
+
+    for(Vertex::ConstVertexIterator it(v0->colocals()); !it.isDone(); it.advance())
+    {
+        if (it.current() == v1)
+        {
+            // Skip degenerate edges.
+            return false;
+        }
+    }
+
+    // Make sure edge has not been added yet.
+    Edge * edge = findEdge(i, j);
+
+    return edge == NULL || edge->face == NULL; // We ignore edges that don't have an adjacent face yet, since this face could become the edge's face.
+}
+
+Edge * Mesh::addEdge(uint i, uint j)
+{
+    nvCheck(i != j);
+
+    Edge * edge = findEdge(i, j);
+
+    if (edge != NULL) {
+        // Edge may already exist, but its face must not be set.
+        nvDebugCheck(edge->face == NULL);
+
+        // Nothing else to do!
+
+    }
+    else {
+        // Add new edge.
+
+        // Lookup pair.
+        Edge * pair = findEdge(j, i);
+
+        if (pair != NULL)
+        {
+            // Create edge with same id.
+            edge = new Edge(pair->id + 1);
+
+            // Link edge pairs.
+            edge->pair = pair;
+            pair->pair = edge;
+
+            // @@ I'm not sure this is necessary!
+            pair->vertex->setEdge(pair);
+        }
+        else
+        {
+            // Create edge.
+            edge = new Edge(2*m_edgeArray.count());
+
+            // Add only unpaired edges.
+            m_edgeArray.append(edge);
+        }
+
+        edge->vertex = m_vertexArray[i];
+        m_edgeMap.add(Key(i,j), edge);
+    }
+
+    // Face and Next are set by addFace.
+
+    return edge;
+}
+
+
+/// Find edge, test all colocals.
+Edge * Mesh::findEdge(uint i, uint j) const
+{
+    Edge * edge = NULL;
+
+    const Vertex * v0 = vertexAt(i);
+    const Vertex * v1 = vertexAt(j);
+
+    // Test all colocal pairs.
+    for(Vertex::ConstVertexIterator it0(v0->colocals()); !it0.isDone(); it0.advance())
+    {
+        for(Vertex::ConstVertexIterator it1(v1->colocals()); !it1.isDone(); it1.advance())
+        {
+            Key key(it0.current()->id, it1.current()->id);
+
+            if (edge == NULL) {
+                m_edgeMap.get(key, &edge);
+#if !defined(_DEBUG)
+                if (edge != NULL) return edge;
+#endif
+            }
+            else {
+                // Make sure that only one edge is found.
+                nvDebugCheck(!m_edgeMap.get(key));
+            }
+        }
+    }
+
+    return edge;
+}
+
+/// Link boundary edges once the mesh has been created.
+void Mesh::linkBoundary()
+{
+    nvDebug("--- Linking boundaries:\n");
+
+    int num = 0;
+
+    // Create boundary edges.
+    uint edgeCount = this->edgeCount();
+    for(uint e = 0; e < edgeCount; e++)
+    {
+        Edge * edge = edgeAt(e);
+        if (edge != NULL && edge->pair == NULL) {
+            Edge * pair = new Edge(edge->id + 1);
+
+            uint i = edge->from()->id;
+            uint j = edge->next->from()->id;
+
+            Key key(j,i);
+            nvCheck(!m_edgeMap.get(key));
+
+            pair->vertex = m_vertexArray[j];
+            m_edgeMap.add(key, pair);
+
+            edge->pair = pair;
+            pair->pair = edge;
+
+            num++;
+        }
+    }
+
+    // Link boundary edges.
+    for (uint e = 0; e < edgeCount; e++) {
+        Edge * edge = edgeAt(e);
+        if (edge != NULL && edge->pair->face == NULL) {
+            linkBoundaryEdge(edge->pair);
+        }
+    }
+
+    nvDebug("---   %d boundary edges.\n", num);
+}
+
+/// Link this boundary edge.
+void Mesh::linkBoundaryEdge(Edge * edge)
+{
+    nvCheck(edge->face == NULL);
+
+    // Make sure next pointer has not been set. @@ We want to be able to relink boundary edges after mesh changes.
+    //nvCheck(edge->next() == NULL);
+
+    Edge * next = edge;
+    while(next->pair->face != NULL) {
+        // Get pair prev
+        Edge * e = next->pair->next;
+        while (e->next != next->pair) {
+            e = e->next;
+        }
+        next = e;
+    }
+    edge->setNext(next->pair);
+
+    // Adjust vertex edge, so that it's the boundary edge. (required for isBoundary())
+    if (edge->vertex->edge != edge)
+    {
+        // Multiple boundaries in the same edge.
+        //nvCheck( edge->vertex()->edge() == NULL || edge->vertex()->edge()->face() != NULL );
+        edge->vertex->edge = edge;
+    }
+}
+
+
+/// Convert to tri mesh.
+TriMesh * Mesh::toTriMesh() const
+{
+    uint triangleCount = 0;
+
+    // Count triangle faces.
+    const uint faceCount = this->faceCount();
+    for(uint f = 0; f < faceCount; f++)
+    {
+        const Face * face = faceAt(f);
+        triangleCount += face->edgeCount() - 2;
+    }
+
+    TriMesh * triMesh = new TriMesh(triangleCount, vertexCount());
+
+    // Add vertices.
+    Array<TriMesh::Vertex> & vertices = triMesh->vertices();
+
+    const uint vertexCount = this->vertexCount();
+    for(uint v = 0; v < vertexCount; v++)
+    {
+        const Vertex * vertex = vertexAt(v);
+
+        TriMesh::Vertex triVertex;
+        triVertex.id = vertices.count();
+        triVertex.pos = vertex->pos;
+        triVertex.nor = vertex->nor;
+        triVertex.tex = vertex->tex;
+
+        vertices.append(triVertex);
+    }
+
+    // Add triangles.
+    Array<TriMesh::Face> & triangles = triMesh->faces();
+
+    for(uint f = 0; f < faceCount; f++)
+    {
+        const Face * face = faceAt(f);
+
+        // @@ Triangulate arbitrary polygons correctly.
+        const uint v0 = face->edge->vertex->id;
+        uint v1 = face->edge->next->vertex->id;
+
+        for(Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+        {
+            uint v2 = it.current()->vertex->id;
+
+            // Skip the first two vertices.
+            if (v2 == v0 || v2 == v1) continue;
+
+            TriMesh::Face triangle;
+            triangle.id = triangles.count();
+            triangle.v[0] = v0;
+            triangle.v[1] = v1;
+            triangle.v[2] = v2;
+
+            v1 = v2;
+
+            triangles.append(triangle);
+        }
+    }
+
+    return triMesh;
+}
+
+QuadTriMesh * Mesh::toQuadTriMesh() const
+{
+    MeshBuilder builder;
+
+    const uint vertexCount = this->vertexCount();
+    builder.hintVertexCount(vertexCount);
+
+    for(uint v = 0; v < vertexCount; v++)
+    {
+        const Vertex * vertex = vertexAt(v);
+
+        builder.addPosition(vertex->pos);
+        builder.addNormal(vertex->nor);
+        builder.addTexCoord(vertex->tex);
+    }
+
+    const uint faceCount = this->faceCount();
+    builder.hintTriangleCount(faceCount);
+
+    for(uint f = 0; f < faceCount; f++)
+    {
+        const Face * face = faceAt(f);
+
+        builder.beginPolygon();
+
+        for(Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+        {
+            uint v = it.current()->vertex->id;
+            builder.addVertex(v, v, v);
+        }
+
+        builder.endPolygon();
+    }
+
+    builder.done();
+
+    return builder.buildQuadTriMesh();
+}
+
+
+// Triangulate in place.
+void Mesh::triangulate() {
+
+    bool all_triangles = true;
+
+    const uint faceCount = m_faceArray.count();
+    for (uint f = 0; f < faceCount; f++) {
+        Face * face = m_faceArray[f];
+        if (face->edgeCount() != 3) {
+            all_triangles = false;
+            break;
+        }
+    }
+
+    if (all_triangles) {
+        return;
+    }
+
+
+    // Do not touch vertices, but rebuild edges and faces.
+    Array<Edge *> edgeArray;
+    Array<Face *> faceArray;
+
+    swap(edgeArray, m_edgeArray);
+    swap(faceArray, m_faceArray);
+    m_edgeMap.clear();
+
+    for (uint f = 0; f < faceCount; f++) {
+        Face * face = faceArray[f];
+
+        // Trivial fan-like triangulation.
+        const uint v0 = face->edge->vertex->id;
+        uint v2, v1 = -1;
+
+        for (Face::EdgeIterator it(face->edges()); !it.isDone(); it.advance()) {
+            Edge * edge = it.current();
+            v2 = edge->to()->id;
+            if (v2 == v0) break;
+            if (v1 != -1) addFace(v0, v1, v2);
+            v1 = v2;
+        }
+    }
+
+    nvDebugCheck(m_faceArray.count() > faceCount); // triangle count > face count
+
+    linkBoundary();
+
+    deleteAll(edgeArray);
+    deleteAll(faceArray);
+}
+
+
+/*
+Fixing T-junctions.
+
+- Find T-junctions. Find  vertices that are on an edge. 
+    - This test is approximate.
+    - Insert edges on a spatial index to speedup queries.
+    - Consider only open edges, that is edges that have no pairs.
+    - Consider only vertices on boundaries.
+- Close T-junction.
+    - Split edge.
+
+*/
+bool Mesh::splitBoundaryEdges() {
+    
+    Array<Vertex *> boundaryVertices;
+
+    foreach(i, m_vertexArray) {
+        Vertex * v = m_vertexArray[i];
+        if (v->isBoundary()) {
+            boundaryVertices.append(v);
+        }
+    }
+
+    nvDebug("Fixing T-junctions:\n");
+
+    int splitCount = 0;
+
+    foreach(v, boundaryVertices) {
+        Vertex * vertex = boundaryVertices[v];
+
+        Vector3 x0 = vertex->pos;
+
+        // Find edges that this vertex overlaps with.
+        foreach(e, m_edgeArray) {
+        //for (uint e = 0; e < m_edgeArray.count(); e++) {
+            Edge * edge = m_edgeArray[e];
+            if (edge != NULL && edge->isBoundary()) {
+
+                if (edge->from() == vertex || edge->to() == vertex) {
+                    continue;
+                }
+
+                Vector3 x1 = edge->from()->pos;
+                Vector3 x2 = edge->to()->pos;
+
+                Vector3 v01 = x0 - x1;
+                Vector3 v21 = x2 - x1;
+
+                float l = length(v21);
+                float d = length(cross(v01, v21)) / l;
+
+                if (isZero(d)) {
+                    float t = dot(v01, v21) / (l * l);
+
+                    // @@ Snap x0 to x1 or x2, if too close? No, do vertex snapping elsewhere.
+                    /*if (equal(t, 0.0f, 0.01f)) {
+                        //vertex->setPos(x1);
+                    }
+                    else if (equal(t, 1.0f, 0.01f)) {
+                        //vertex->setPos(x2);
+                    }
+                    else*/
+                    if (t > 0.0f + NV_EPSILON && t < 1.0f - NV_EPSILON) {
+                        nvDebugCheck(equal(lerp(x1, x2, t), x0));
+
+                        Vertex * splitVertex = splitBoundaryEdge(edge, t, x0);
+                        vertex->linkColocal(splitVertex);   // @@ Should we do this here?
+                        splitCount++;
+                    }
+                }
+            }
+        }
+    }
+
+    nvDebug(" - %d edges split.\n", splitCount);
+
+    nvDebugCheck(isValid());
+
+    return splitCount != 0;
+}
+
+
+// For this to be effective, we have to fix the boundary junctions first.
+Edge * Mesh::sewBoundary(Edge * startEdge) {
+    nvDebugCheck(startEdge->face == NULL);
+
+    // @@ We may want to be more conservative linking colocals in order to preserve the input topology. One way of doing that is by linking colocals only 
+    // if the vertices next to them are linked as well. That is, by sewing boundaries after detecting them. If any pair of consecutive edges have their first
+    // and last vertex in the same position, then it can be linked.
+
+    Edge * lastBoundarySeen = startEdge;
+
+    nvDebug("Sewing Boundary:\n");
+
+    int count = 0;
+    int sewnCount = 0;
+
+    Edge * edge = startEdge;
+    do {
+        nvDebugCheck(edge->face == NULL);
+
+        Edge * edge_a = edge;
+        Edge * edge_b = edge->prev;
+
+        Edge * pair_a = edge_a->pair;
+        Edge * pair_b = edge_b->pair;
+
+        Vertex * v0a = edge_a->to();
+        Vertex * v0b = edge_b->from();
+        Vertex * v1a = edge_a->from();
+        Vertex * v1b = edge_b->to();
+
+        nvDebugCheck(v1a->isColocal(v1b));
+
+        /*
+        v0b +      _+ v0a
+             \     /
+            b \   / a
+               \|/
+            v1b + v1a
+        */
+
+        // @@ This should not happen while sewing, but it may be produced somewhere else.
+        nvDebugCheck(edge_a != edge_b);
+
+        if (v0a->pos == v0b->pos) {
+
+            // Link vertices.
+            v0a->linkColocal(v0b);
+            
+            // Remove edges to be collapsed.
+            disconnect(edge_a);
+            disconnect(edge_b);
+            disconnect(pair_a);
+            disconnect(pair_b);
+
+            // Link new boundary edges.
+            Edge * prevBoundary = edge_b->prev;
+            Edge * nextBoundary = edge_a->next;
+            if (nextBoundary != NULL) {
+                nvDebugCheck(nextBoundary->face == NULL);
+                nvDebugCheck(prevBoundary->face == NULL);
+                nextBoundary->setPrev(prevBoundary);
+            
+                // Make sure boundary vertex points to boundary edge.
+                v0a->setEdge(nextBoundary); // This updates all colocals.
+            }
+            lastBoundarySeen = prevBoundary;
+
+            // Creat new edge.
+            Edge * newEdge_a = addEdge(v0a->id, v1a->id);   // pair_a->from()->id, pair_a->to()->id
+            Edge * newEdge_b = addEdge(v1b->id, v0b->id);
+
+            newEdge_a->pair = newEdge_b;
+            newEdge_b->pair = newEdge_a;
+
+            newEdge_a->face = pair_a->face;
+            newEdge_b->face = pair_b->face;
+
+            newEdge_a->setNext(pair_a->next);
+            newEdge_a->setPrev(pair_a->prev);
+
+            newEdge_b->setNext(pair_b->next);
+            newEdge_b->setPrev(pair_b->prev);
+
+            delete edge_a;
+            delete edge_b;
+            delete pair_a;
+            delete pair_b;
+
+            edge = nextBoundary;    // If nextBoundary is NULL we have closed the loop.
+            sewnCount++;
+        }
+        else {
+            edge = edge->next;
+        }
+        
+        count++;
+    } while(edge != NULL && edge != lastBoundarySeen);
+
+    nvDebug(" - Sewn %d out of %d.\n", sewnCount, count);
+
+    if (lastBoundarySeen != NULL) {
+        nvDebugCheck(lastBoundarySeen->face == NULL);
+    }
+
+    return lastBoundarySeen;
+}
+
+
+// @@ We must always disconnect edge pairs simultaneously.
+void Mesh::disconnect(Edge * edge) {
+    nvDebugCheck(edge != NULL);
+
+    // Remove from edge list.
+    if ((edge->id & 1) == 0) {
+        nvDebugCheck(m_edgeArray[edge->id / 2] == edge);
+        m_edgeArray[edge->id / 2] = NULL;
+    }
+
+    // Remove edge from map. @@ Store map key inside edge?
+    nvDebugCheck(edge->from() != NULL && edge->to() != NULL);
+    bool removed = m_edgeMap.remove(Key(edge->from()->id, edge->to()->id));
+    nvDebugCheck(removed == true);
+
+    // Disconnect from vertex.
+    if (edge->vertex != NULL) {
+        if (edge->vertex->edge == edge) {
+            if (edge->prev && edge->prev->pair) {
+                edge->vertex->edge = edge->prev->pair;
+            }
+            else if (edge->pair && edge->pair->next) {
+                edge->vertex->edge = edge->pair->next;
+            }
+            else {
+                edge->vertex->edge = NULL;
+                // @@ Remove disconnected vertex?
+            }
+        }
+        //edge->setVertex(NULL);
+    }
+
+    // Disconnect from face.
+    if (edge->face != NULL) {
+        if (edge->face->edge == edge) {
+            if (edge->next != NULL && edge->next != edge) {
+                edge->face->edge = edge->next;
+            }
+            else if (edge->prev != NULL && edge->prev != edge) {
+                edge->face->edge = edge->prev;
+            }
+            else {
+                edge->face->edge = NULL;
+                // @@ Remove disconnected face?
+            }
+        }
+        //edge->setFace(NULL);
+    }
+
+    // @@ Hack, we don't disconnect from pair, because pair needs us to remove itself from the map.
+    // Disconect from pair.
+    /*if (edge->pair != NULL) {
+        if (edge->pair->pair == edge) {
+            edge->pair->setPair(NULL);
+        }
+        //edge->setPair(NULL);
+    }*/
+
+    // Disconnect from previous.
+    if (edge->prev) {
+        if (edge->prev->next == edge) {
+            edge->prev->setNext(NULL);
+        }
+        //edge->setPrev(NULL);
+    }
+
+    // Disconnect from next.
+    if (edge->next) {
+        if (edge->next->prev == edge) {
+            edge->next->setPrev(NULL);
+        }
+        //edge->setNext(NULL);
+    }
+}
+
+
+void Mesh::remove(Edge * edge) {
+    nvDebugCheck(edge != NULL);
+
+    disconnect(edge);
+
+    delete edge;
+}
+
+void Mesh::remove(Vertex * vertex) {
+    nvDebugCheck(vertex != NULL);
+
+    // Remove from vertex list.
+    m_vertexArray[vertex->id] = NULL;
+
+    // Disconnect from colocals.
+    vertex->unlinkColocal();
+
+    // Disconnect from edges.
+    if (vertex->edge != NULL) {
+        // @@ Removing a connected vertex is asking for trouble...
+        if (vertex->edge->vertex == vertex) {
+            // @@ Connect edge to a colocal?
+            vertex->edge->vertex = NULL;
+        }
+
+        vertex->setEdge(NULL);
+    }
+
+    delete vertex;
+}
+
+void Mesh::remove(Face * face) {
+    nvDebugCheck(face != NULL);
+
+    // Remove from face list.
+    m_faceArray[face->id] = NULL;
+
+    // Disconnect from edges.
+    if (face->edge != NULL) {
+        nvDebugCheck(face->edge->face == face);
+
+        face->edge->face = NULL;
+
+        face->edge = NULL;
+    }
+
+    delete face;
+}
+
+
+void Mesh::compactEdges() {
+    const uint edgeCount = m_edgeArray.count();
+
+    uint c = 0;
+    for (uint i = 0; i < edgeCount; i++) {
+        if (m_edgeArray[i] != NULL) {
+            if (i != c) {
+                m_edgeArray[c] = m_edgeArray[i];
+                m_edgeArray[c]->id = 2 * c;
+                if (m_edgeArray[c]->pair != NULL) {
+                    m_edgeArray[c]->pair->id = 2 * c + 1;
+                }
+            }
+            c++;
+        }
+    }
+
+    m_edgeArray.resize(c);
+}
+
+
+void Mesh::compactVertices() {
+    const uint vertexCount = m_vertexArray.count();
+
+    uint c = 0;
+    for (uint i = 0; i < vertexCount; i++) {
+        if (m_vertexArray[i] != NULL) {
+            if (i != c) {
+                m_vertexArray[c] = m_vertexArray[i];
+                m_vertexArray[c]->id = c;
+            }
+            c++;
+        }
+    }
+
+    m_vertexArray.resize(c);
+
+    // @@ Generate xref array for external attributes.
+}
+
+
+void Mesh::compactFaces() {
+    const uint faceCount = m_faceArray.count();
+
+    uint c = 0;
+    for (uint i = 0; i < faceCount; i++) {
+        if (m_faceArray[i] != NULL) {
+            if (i != c) {
+                m_faceArray[c] = m_faceArray[i];
+                m_faceArray[c]->id = c;
+            }
+            c++;
+        }
+    }
+
+    m_faceArray.resize(c);
+}
+
+
+Vertex * Mesh::splitBoundaryEdge(Edge * edge, float t, const Vector3 & pos) {
+
+    /*
+      We want to go from this configuration:
+           
+            +   +
+            |   ^
+       edge |<->|  pair
+            v   |
+            +   +
+      
+      To this one:
+
+            +   +
+            |   ^
+         e0 |<->| p0
+            v   |
+     vertex +   + 
+            |   ^
+         e1 |<->| p1
+            v   |
+            +   +
+
+    */
+
+
+    Edge * pair = edge->pair;
+
+    // Make sure boundaries are linked.
+    nvDebugCheck(pair != NULL); 
+
+    // Make sure edge is a boundary edge.
+    nvDebugCheck(pair->face == NULL);
+
+    // Add new vertex.
+    Vertex * vertex = addVertex(pos);
+    vertex->nor = lerp(edge->from()->nor, edge->to()->nor, t);
+    vertex->tex = lerp(edge->from()->tex, edge->to()->tex, t);
+    vertex->col = lerp(edge->from()->col, edge->to()->col, t);
+
+    disconnect(edge);
+    disconnect(pair);
+
+    // Add edges.
+    Edge * e0 = addEdge(edge->from()->id, vertex->id);
+    Edge * p0 = addEdge(vertex->id, pair->to()->id);
+
+    Edge * e1 = addEdge(vertex->id, edge->to()->id);
+    Edge * p1 = addEdge(pair->from()->id, vertex->id);
+
+    // Link edges.
+    e0->setNext(e1);
+    p1->setNext(p0);
+
+    e0->setPrev(edge->prev);
+    e1->setNext(edge->next);
+
+    p1->setPrev(pair->prev);
+    p0->setNext(pair->next);
+
+    nvDebugCheck(e0->next == e1);
+    nvDebugCheck(e1->prev == e0);
+
+    nvDebugCheck(p1->next == p0);
+    nvDebugCheck(p0->prev == p1);
+
+    nvDebugCheck(p0->pair == e0);
+    nvDebugCheck(e0->pair == p0);
+
+    nvDebugCheck(p1->pair == e1);
+    nvDebugCheck(e1->pair == p1);
+
+    // Link faces.
+    e0->face = edge->face;
+    e1->face = edge->face;
+
+    // Link vertices.
+    edge->from()->setEdge(e0);
+    vertex->setEdge(e1);
+
+    delete edge;
+    delete pair;
+
+    return vertex;
+}
+
+#if 0
+// Without introducing new vertices.
+void Mesh::splitBoundaryEdge(Edge * edge, Vertex * vertex) {
+
+    /*
+      We want to go from this configuration:
+
+            |   | pn
+            +   +
+            |   ^
+            |   |
+       edge |<->| pair
+            |   |
+            v   |
+            +   +
+            |   | pp
+      
+      To this one:
+          \       /
+           \     /
+            +   +
+            |   ^
+         e0 |<->| p0
+            v   |
+     vertex +   + 
+            |   ^
+         e1 |<->| p1
+            v   |
+            +   +
+           /     \
+          /       \
+    */
+
+
+    Edge * pair = edge->pair;
+    Edge * pn = pair->next();
+    Edge * pp = pair->prev();
+
+    // Make sure boundaries are linked.
+    nvDebugCheck(pair != NULL);
+
+    // Make sure edge is a boundary edge.
+    nvDebugCheck(pair->face() == NULL);
+
+    nvDebugCheck(edge->isValid());
+    nvDebugCheck(pair->isValid());
+
+    disconnect(edge);
+    disconnect(pair);
+
+    // Add edges.
+    Edge * e0 = addEdge(edge->from()->id(), vertex->id());
+    Edge * e1 = addEdge(vertex->id(), edge->to()->id());
+
+    // Link faces.
+    e0->setFace(edge->face());
+    e1->setFace(edge->face());
+
+    // Link pairs.
+    Edge * p0 = findEdge(vertex->id(), pair->to()->id());
+    if (p0 == NULL) {
+        p0 = addEdge(vertex->id(), pair->to()->id());
+        pn->setPrev(p0);
+    }
+    else {
+        nvDebugCheck(p0->face() != NULL);
+        if (e0->prev() != NULL) {
+            pn->setPrev(e0->prev());
+        }
+        else {
+            nvDebugCheck(pn == e0);
+        }
+    }
+    
+    Edge * p1 = findEdge(pair->from()->id(), vertex->id());
+    if (p1 == NULL) {
+        p1 = addEdge(pair->from()->id(), vertex->id());
+        pp->setNext(p1);
+    }
+    else {
+        nvDebugCheck(p1->face() != NULL);
+        if (e1->next() != NULL) {
+            pp->setPrev(e1->next());
+        }
+        else {
+            nvDebugCheck(pp == e1);
+        }
+    }
+
+    // Link edges.
+    e0->setNext(e1); // e1->setPrev(e0)
+
+    if (p0->face() == p1->face()) { // can be null
+        p1->setNext(p0); // p0->setPrev(p1)
+    }
+    else {
+        //if (p1->face() == NULL) p1->setNext(
+    }
+    
+
+    e0->setPrev(edge->prev());
+    e1->setNext(edge->next());
+
+    nvDebugCheck(e0->pair == p0);
+    nvDebugCheck(e1->pair == p1);
+    nvDebugCheck(p0->pair == e0);
+    nvDebugCheck(p1->pair == e1);
+
+    nvDebugCheck(e0->isValid());
+    nvDebugCheck(e1->isValid());
+    nvDebugCheck(pp->isValid());
+    nvDebugCheck(pn->isValid());
+
+    nvDebugCheck(e0->pair->isValid());
+    nvDebugCheck(e1->pair->isValid());
+    nvDebugCheck(pp->pair->isValid());
+    nvDebugCheck(pn->pair->isValid());
+
+    nvDebugCheck(edge->face->isValid());
+
+    if (pn->pair->face != NULL) {
+        nvDebugCheck(pn->pair->face->isValid());
+    }
+
+    if (pp->pair->face() != NULL) {
+        nvDebugCheck(pn->pair->face->isValid());
+    }
+
+    if (p0->face != NULL) {
+        nvDebugCheck(p0->face->isValid());
+    }
+
+    if (p1->face() != NULL) {
+        nvDebugCheck(p1->face()->isValid());
+    }
+
+    nvDebugCheck(isValid()); // Only for extreme debugging.
+
+    // Link vertices.
+    edge->from()->setEdge(e0);
+    vertex->setEdge(p0);
+
+    delete edge;
+    delete pair;
+}
+#endif
+
+bool Mesh::isValid() const
+{
+    // Make sure all edges are valid.
+    const uint edgeCount = m_edgeArray.count();
+    for (uint e = 0; e < edgeCount; e++) {
+        Edge * edge = m_edgeArray[e];
+        if (edge != NULL) {
+            if (edge->id != 2*e) {
+                return false;
+            }
+            if (!edge->isValid()) {
+                return false;
+            }
+
+            if (edge->pair->id != 2*e+1) {
+                return false;
+            }
+            if (!edge->pair->isValid()) {
+                return false;
+            }
+        }
+    }
+
+    // @@ Make sure all faces are valid.
+
+    // @@ Make sure all vertices are valid.
+
+    return true;
+}
diff --git a/thirdparty/thekla_atlas/nvmesh/halfedge/Mesh.h b/thirdparty/thekla_atlas/nvmesh/halfedge/Mesh.h
new file mode 100644
index 0000000000..c202c2ef9a
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/halfedge/Mesh.h
@@ -0,0 +1,274 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#pragma once
+#ifndef NV_MESH_HALFEDGE_MESH_H
+#define NV_MESH_HALFEDGE_MESH_H
+
+#include "nvmesh/nvmesh.h"
+#include "nvcore/Array.h"
+#include "nvcore/HashMap.h"
+
+/*
+If I were to redo this again, there are a number of things that I would do differently.
+- Edge map is only useful when importing a mesh to guarantee the result is two-manifold. However, when manipulating the mesh
+  it's a pain to maintain the map up to date.
+- Edge array only points to the even vertices. There's no good reason for that. The map becomes required to traverse all edges
+  or you have to make sure edges are properly paired.
+- Linked boundaries. It's cleaner to assume a NULL pair means a boundary edge. Makes easier to seal boundaries. The only reason
+  why we link boundaries is to simplify traversal, but that could be done with two helper functions (nextBoundary, prevBoundary).
+- Minimize the amount of state that needs to be set in a certain way:
+    - boundary vertices point to boundary edge.
+- Remove parenthesis! Make some members public.
+- Remove member functions with side effects:
+    - e->setNext(n) modifies e->next and n->prev, instead use "link(e, n)", or "e->next = n, n->prev = e"
+*/
+
+
+namespace nv
+{
+    class Vector3;
+    class TriMesh;
+    class QuadTriMesh;
+    //template <typename T> struct Hash<Mesh::Key>;
+
+    namespace HalfEdge
+    {
+        class Edge;
+        class Face;
+        class Vertex;
+
+        /// Simple half edge mesh designed for dynamic mesh manipulation.
+        class Mesh
+        {
+        public:
+
+            Mesh();
+            Mesh(const Mesh * mesh);
+            ~Mesh();
+
+            void clear();
+
+            Vertex * addVertex(const Vector3 & pos);
+            //Vertex * addVertex(uint id, const Vector3 & pos);
+            //void addVertices(const Mesh * mesh);
+
+            void linkColocals();
+            void linkColocalsWithCanonicalMap(const Array<uint> & canonicalMap);
+            void resetColocalLinks();
+
+            Face * addFace();
+            Face * addFace(uint v0, uint v1, uint v2);
+            Face * addFace(uint v0, uint v1, uint v2, uint v3);
+            Face * addFace(const Array<uint> & indexArray);
+            Face * addFace(const Array<uint> & indexArray, uint first, uint num);
+            //void addFaces(const Mesh * mesh);
+
+            // These functions disconnect the given element from the mesh and delete it.
+            void disconnect(Edge * edge);
+            void disconnectPair(Edge * edge);
+            void disconnect(Vertex * vertex);
+            void disconnect(Face * face);
+
+            void remove(Edge * edge);
+            void remove(Vertex * vertex);
+            void remove(Face * face);
+
+            // Remove holes from arrays and reassign indices.
+            void compactEdges();
+            void compactVertices();
+            void compactFaces();
+
+            void triangulate();
+
+            void linkBoundary();
+            
+            bool splitBoundaryEdges(); // Returns true if any split was made.
+
+            // Sew the boundary that starts at the given edge, returns one edge that still belongs to boundary, or NULL if boundary closed.
+            HalfEdge::Edge * sewBoundary(Edge * startEdge);
+
+
+            // Vertices
+            uint vertexCount() const { return m_vertexArray.count(); }
+            const Vertex * vertexAt(int i) const { return m_vertexArray[i]; }
+            Vertex * vertexAt(int i) { return m_vertexArray[i]; }
+
+            uint colocalVertexCount() const { return m_colocalVertexCount; }
+
+            // Faces
+            uint faceCount() const { return m_faceArray.count(); }
+            const Face * faceAt(int i) const { return m_faceArray[i]; }
+            Face * faceAt(int i) { return m_faceArray[i]; }
+
+            // Edges
+            uint edgeCount() const { return m_edgeArray.count();  }
+            const Edge * edgeAt(int i) const { return m_edgeArray[i]; }
+            Edge * edgeAt(int i) { return m_edgeArray[i]; }
+
+            class ConstVertexIterator;
+
+            class VertexIterator
+            {
+                friend class ConstVertexIterator;
+            public:
+                VertexIterator(Mesh * mesh) : m_mesh(mesh), m_current(0) { }
+
+                virtual void advance() { m_current++; }
+                virtual bool isDone() const { return m_current == m_mesh->vertexCount(); }
+                virtual Vertex * current() const { return m_mesh->vertexAt(m_current); }
+
+            private:
+                HalfEdge::Mesh * m_mesh;
+                uint m_current;
+            };
+            VertexIterator vertices() { return VertexIterator(this); }
+
+            class ConstVertexIterator
+            {
+            public:
+                ConstVertexIterator(const Mesh * mesh) : m_mesh(mesh), m_current(0) { }
+                ConstVertexIterator(class VertexIterator & it) : m_mesh(it.m_mesh), m_current(it.m_current) { }
+
+                virtual void advance() { m_current++; }
+                virtual bool isDone() const { return m_current == m_mesh->vertexCount(); }
+                virtual const Vertex * current() const { return m_mesh->vertexAt(m_current); }
+
+            private:
+                const HalfEdge::Mesh * m_mesh;
+                uint m_current;
+            };
+            ConstVertexIterator vertices() const { return ConstVertexIterator(this); }
+
+            class ConstFaceIterator;
+
+            class FaceIterator
+            {
+                friend class ConstFaceIterator;
+            public:
+                FaceIterator(Mesh * mesh) : m_mesh(mesh), m_current(0) { }
+
+                virtual void advance() { m_current++; }
+                virtual bool isDone() const { return m_current == m_mesh->faceCount(); }
+                virtual Face * current() const { return m_mesh->faceAt(m_current); }
+
+            private:
+                HalfEdge::Mesh * m_mesh;
+                uint m_current;
+            };
+            FaceIterator faces() { return FaceIterator(this); }
+
+            class ConstFaceIterator
+            {
+            public:
+                ConstFaceIterator(const Mesh * mesh) : m_mesh(mesh), m_current(0) { }
+                ConstFaceIterator(const FaceIterator & it) : m_mesh(it.m_mesh), m_current(it.m_current) { }
+
+                virtual void advance() { m_current++; }
+                virtual bool isDone() const { return m_current == m_mesh->faceCount(); }
+                virtual const Face * current() const { return m_mesh->faceAt(m_current); }
+
+            private:
+                const HalfEdge::Mesh * m_mesh;
+                uint m_current;
+            };
+            ConstFaceIterator faces() const { return ConstFaceIterator(this); }
+
+            class ConstEdgeIterator;
+
+            class EdgeIterator
+            {
+                friend class ConstEdgeIterator;
+            public:
+                EdgeIterator(Mesh * mesh) : m_mesh(mesh), m_current(0) { }
+
+                virtual void advance() { m_current++; }
+                virtual bool isDone() const { return m_current == m_mesh->edgeCount(); }
+                virtual Edge * current() const { return m_mesh->edgeAt(m_current); }
+
+            private:
+                HalfEdge::Mesh * m_mesh;
+                uint m_current;
+            };
+            EdgeIterator edges() { return EdgeIterator(this); }
+
+            class ConstEdgeIterator
+            {
+            public:
+                ConstEdgeIterator(const Mesh * mesh) : m_mesh(mesh), m_current(0) { }
+                ConstEdgeIterator(const EdgeIterator & it) : m_mesh(it.m_mesh), m_current(it.m_current) { }
+
+                virtual void advance() { m_current++; }
+                virtual bool isDone() const { return m_current == m_mesh->edgeCount(); }
+                virtual const Edge * current() const { return m_mesh->edgeAt(m_current); }
+
+            private:
+                const HalfEdge::Mesh * m_mesh;
+                uint m_current;
+            };
+            ConstEdgeIterator edges() const { return ConstEdgeIterator(this); }
+
+            // @@ Add half-edge iterator.
+
+
+
+            // Convert to tri mesh.
+            TriMesh * toTriMesh() const;
+            QuadTriMesh * toQuadTriMesh() const;
+
+            bool isValid() const;
+
+        public:
+
+            // Error status:
+            mutable uint errorCount;
+            mutable uint errorIndex0;
+            mutable uint errorIndex1;
+
+        private:
+
+            bool canAddFace(const Array<uint> & indexArray, uint first, uint num) const;
+            bool canAddEdge(uint i, uint j) const;
+            Edge * addEdge(uint i, uint j);
+
+            Edge * findEdge(uint i, uint j) const;
+
+            void linkBoundaryEdge(Edge * edge);
+            Vertex * splitBoundaryEdge(Edge * edge, float t, const Vector3 & pos);
+            void splitBoundaryEdge(Edge * edge, Vertex * vertex);
+
+        private:
+
+            Array<Vertex *> m_vertexArray;
+            Array<Edge *> m_edgeArray;
+            Array<Face *> m_faceArray;
+
+            struct Key {
+                Key() {}
+                Key(const Key & k) : p0(k.p0), p1(k.p1) {}
+                Key(uint v0, uint v1) : p0(v0), p1(v1) {}
+                void operator=(const Key & k) { p0 = k.p0; p1 = k.p1; }
+                bool operator==(const Key & k) const { return p0 == k.p0 && p1 == k.p1; }
+
+                uint p0;
+                uint p1;
+            };
+            friend struct Hash<Mesh::Key>;
+
+            HashMap<Key, Edge *> m_edgeMap;
+
+            uint m_colocalVertexCount;
+
+        };
+        /*
+        // This is a much better hash than the default and greatly improves performance!
+        template <> struct hash<Mesh::Key>
+        {
+        uint operator()(const Mesh::Key & k) const { return k.p0 + k.p1; }
+        };
+        */
+
+    } // HalfEdge namespace
+
+} // nv namespace
+
+#endif // NV_MESH_HALFEDGE_MESH_H
diff --git a/thirdparty/thekla_atlas/nvmesh/halfedge/Vertex.cpp b/thirdparty/thekla_atlas/nvmesh/halfedge/Vertex.cpp
new file mode 100644
index 0000000000..66dad69f8a
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/halfedge/Vertex.cpp
@@ -0,0 +1,94 @@
+// This code is in the public domain -- castano@gmail.com
+
+#include "nvmesh.h" // pch
+
+#include "Vertex.h"
+
+#include "nvmath/Vector.inl"
+
+using namespace nv;
+using namespace HalfEdge;
+
+
+// Set first edge of all colocals.
+void Vertex::setEdge(Edge * e)
+{
+    for (VertexIterator it(colocals()); !it.isDone(); it.advance()) { 
+        it.current()->edge = e;
+    }
+}
+
+// Update position of all colocals.
+void Vertex::setPos(const Vector3 & p)
+{
+    for (VertexIterator it(colocals()); !it.isDone(); it.advance()) {
+        it.current()->pos = p;
+    }
+}
+
+
+uint HalfEdge::Vertex::colocalCount() const
+{
+    uint count = 0;
+    for (ConstVertexIterator it(colocals()); !it.isDone(); it.advance()) { ++count; }
+    return count;
+}
+
+uint HalfEdge::Vertex::valence() const
+{
+    uint count = 0;
+    for (ConstEdgeIterator it(edges()); !it.isDone(); it.advance()) { ++count; }
+    return count;
+}
+
+const HalfEdge::Vertex * HalfEdge::Vertex::firstColocal() const
+{
+    uint firstId = id;
+    const Vertex * vertex = this;
+
+    for (ConstVertexIterator it(colocals()); !it.isDone(); it.advance())
+    {
+        if (it.current()->id < firstId) {
+            firstId = vertex->id;
+            vertex = it.current();
+        }
+    }
+
+    return vertex;
+}
+
+HalfEdge::Vertex * HalfEdge::Vertex::firstColocal()
+{
+    Vertex * vertex = this;
+    uint firstId = id;
+
+    for (VertexIterator it(colocals()); !it.isDone(); it.advance())
+    {
+        if (it.current()->id < firstId) {
+            firstId = vertex->id;
+            vertex = it.current();
+        }
+    }
+
+    return vertex;
+}
+
+bool HalfEdge::Vertex::isFirstColocal() const
+{
+    return firstColocal() == this;
+}
+
+bool HalfEdge::Vertex::isColocal(const Vertex * v) const {
+    if (this == v) return true;
+    if (pos != v->pos) return false;
+
+    for (ConstVertexIterator it(colocals()); !it.isDone(); it.advance())
+    {
+        if (v == it.current()) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
diff --git a/thirdparty/thekla_atlas/nvmesh/halfedge/Vertex.h b/thirdparty/thekla_atlas/nvmesh/halfedge/Vertex.h
new file mode 100644
index 0000000000..1c5c8d7141
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/halfedge/Vertex.h
@@ -0,0 +1,221 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#pragma once
+#ifndef NV_MESH_HALFEDGE_VERTEX_H
+#define NV_MESH_HALFEDGE_VERTEX_H
+
+#include "nvmesh/halfedge/Edge.h"
+
+namespace nv
+{
+    namespace HalfEdge { class Vertex; class Face; class Edge; }
+
+    // Half edge vertex.
+    class HalfEdge::Vertex
+    {
+        NV_FORBID_COPY(Vertex);
+    public:
+
+        uint id;
+
+        Edge * edge;
+        Vertex * next;
+        Vertex * prev;
+
+        Vector3 pos;
+        Vector3 nor;
+        Vector2 tex;
+        Vector4 col;
+
+
+        Vertex(uint id) : id(id), edge(NULL), pos(0.0f), nor(0.0f), tex(0.0f), col(0.0f) {
+            next = this;
+            prev = this;
+        }
+
+
+        void setEdge(Edge * e);
+        void setPos(const Vector3 & p);
+
+        uint colocalCount() const;
+        uint valence() const;
+        bool isFirstColocal() const;
+        const Vertex * firstColocal() const;
+        Vertex * firstColocal();
+
+        bool isColocal(const Vertex * v) const;
+
+        
+        void linkColocal(Vertex * v) {
+            next->prev = v;
+            v->next = next; 
+            next = v;
+            v->prev = this;
+        }
+        void unlinkColocal() {
+            next->prev = prev;
+            prev->next = next;
+            next = this;
+            prev = this;
+        }
+
+
+        // @@ Note: This only works if linkBoundary has been called.
+        bool isBoundary() const {
+            return (edge && !edge->face);
+        }
+
+
+        //	for(EdgeIterator it(iterator()); !it.isDone(); it.advance()) { ... }
+        //
+        //	EdgeIterator it(iterator());
+        //	while(!it.isDone()) {
+        //		...
+        //		id.advance(); 
+        //	}
+
+        // Iterator that visits the edges around this vertex in counterclockwise order.
+        class EdgeIterator //: public Iterator<Edge *>
+        {
+        public:
+            EdgeIterator(Edge * e) : m_end(NULL), m_current(e) { }
+
+            virtual void advance()
+            {
+                if (m_end == NULL) m_end = m_current;
+                m_current = m_current->pair->next;
+                //m_current = m_current->prev->pair;
+            }
+
+            virtual bool isDone() const { return m_end == m_current; }
+            virtual Edge * current() const { return m_current; }
+            Vertex * vertex() const { return m_current->vertex; }
+
+        private:
+            Edge * m_end;
+            Edge * m_current;
+        };
+
+        EdgeIterator edges() { return EdgeIterator(edge); }
+        EdgeIterator edges(Edge * e) { return EdgeIterator(e); }
+
+        // Iterator that visits the edges around this vertex in counterclockwise order.
+        class ConstEdgeIterator //: public Iterator<Edge *>
+        {
+        public:
+            ConstEdgeIterator(const Edge * e) : m_end(NULL), m_current(e) { }
+            ConstEdgeIterator(EdgeIterator it) : m_end(NULL), m_current(it.current()) { }
+
+            virtual void advance()
+            {
+                if (m_end == NULL) m_end = m_current;
+                m_current = m_current->pair->next;
+                //m_current = m_current->prev->pair;
+            }
+
+            virtual bool isDone() const { return m_end == m_current; }
+            virtual const Edge * current() const { return m_current; }
+            const Vertex * vertex() const { return m_current->to(); }
+
+        private:
+            const Edge * m_end;
+            const Edge * m_current;
+        };
+
+        ConstEdgeIterator edges() const { return ConstEdgeIterator(edge); }
+        ConstEdgeIterator edges(const Edge * e) const { return ConstEdgeIterator(e); }
+
+
+        // Iterator that visits the edges around this vertex in counterclockwise order.
+        class ReverseEdgeIterator //: public Iterator<Edge *>
+        {
+        public:
+            ReverseEdgeIterator(Edge * e) : m_end(NULL), m_current(e) { }
+
+            virtual void advance()
+            {
+                if (m_end == NULL) m_end = m_current;
+                m_current = m_current->prev->pair;
+            }
+
+            virtual bool isDone() const { return m_end == m_current; }
+            virtual Edge * current() const { return m_current; }
+            Vertex * vertex() const { return m_current->vertex; }
+
+        private:
+            Edge * m_end;
+            Edge * m_current;
+        };
+
+        // Iterator that visits the edges around this vertex in counterclockwise order.
+        class ReverseConstEdgeIterator //: public Iterator<Edge *>
+        {
+        public:
+            ReverseConstEdgeIterator(const Edge * e) : m_end(NULL), m_current(e) { }
+
+            virtual void advance()
+            {
+                if (m_end == NULL) m_end = m_current;
+                m_current = m_current->prev->pair;
+            }
+
+            virtual bool isDone() const { return m_end == m_current; }
+            virtual const Edge * current() const { return m_current; }
+            const Vertex * vertex() const { return m_current->to(); }
+
+        private:
+            const Edge * m_end;
+            const Edge * m_current;
+        };
+
+
+
+        // Iterator that visits all the colocal vertices.
+        class VertexIterator //: public Iterator<Edge *>
+        {
+        public:
+            VertexIterator(Vertex * v) : m_end(NULL), m_current(v) { }
+
+            virtual void advance()
+            {
+                if (m_end == NULL) m_end = m_current;
+                m_current = m_current->next;
+            }
+
+            virtual bool isDone() const { return m_end == m_current; }
+            virtual Vertex * current() const { return m_current; }
+
+        private:
+            Vertex * m_end;
+            Vertex * m_current;
+        };
+
+        VertexIterator colocals() { return VertexIterator(this); }
+
+        // Iterator that visits all the colocal vertices.
+        class ConstVertexIterator //: public Iterator<Edge *>
+        {
+        public:
+            ConstVertexIterator(const Vertex * v) : m_end(NULL), m_current(v) { }
+
+            virtual void advance()
+            {
+                if (m_end == NULL) m_end = m_current;
+                m_current = m_current->next;
+            }
+
+            virtual bool isDone() const { return m_end == m_current; }
+            virtual const Vertex * current() const { return m_current; }
+
+        private:
+            const Vertex * m_end;
+            const Vertex * m_current;
+        };
+
+        ConstVertexIterator colocals() const { return ConstVertexIterator(this); }
+
+    };
+
+} // nv namespace
+
+#endif // NV_MESH_HALFEDGE_VERTEX_H
diff --git a/thirdparty/thekla_atlas/nvmesh/nvmesh.cpp b/thirdparty/thekla_atlas/nvmesh/nvmesh.cpp
new file mode 100644
index 0000000000..d007eda332
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/nvmesh.cpp
@@ -0,0 +1,2 @@
+#include "nvmesh.h" // pch
+
diff --git a/thirdparty/thekla_atlas/nvmesh/nvmesh.h b/thirdparty/thekla_atlas/nvmesh/nvmesh.h
new file mode 100644
index 0000000000..eb6819675d
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/nvmesh.h
@@ -0,0 +1,34 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#pragma once
+#ifndef NV_MESH_H
+#define NV_MESH_H
+
+#include "nvcore/nvcore.h"
+
+// Function linkage
+#if NVMESH_SHARED
+#ifdef NVMESH_EXPORTS
+#define NVMESH_API DLL_EXPORT
+#define NVMESH_CLASS DLL_EXPORT_CLASS
+#else
+#define NVMESH_API DLL_IMPORT
+#define NVMESH_CLASS DLL_IMPORT
+#endif
+#else
+#define NVMESH_API
+#define NVMESH_CLASS
+#endif
+
+#if 1 //USE_PRECOMPILED_HEADERS // If using precompiled headers:
+//#include <string.h> // strlen, strcmp, etc.
+//#include "nvcore/StrLib.h"
+//#include "nvcore/StdStream.h"
+//#include "nvcore/Memory.h"
+//#include "nvcore/Debug.h"
+//#include "nvmath/Vector.h"
+//#include "nvcore/Array.h"
+//#include "nvcore/HashMap.h"
+#endif
+
+#endif // NV_MESH_H
diff --git a/thirdparty/thekla_atlas/nvmesh/param/Atlas.cpp b/thirdparty/thekla_atlas/nvmesh/param/Atlas.cpp
new file mode 100644
index 0000000000..4e41e76695
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/Atlas.cpp
@@ -0,0 +1,1515 @@
+// Copyright NVIDIA Corporation 2006 -- Ignacio Castano <icastano@nvidia.com>
+
+#include "nvmesh.h" // pch
+
+#include "Atlas.h"
+#include "Util.h"
+#include "AtlasBuilder.h"
+#include "AtlasPacker.h"
+#include "SingleFaceMap.h"
+#include "OrthogonalProjectionMap.h"
+#include "LeastSquaresConformalMap.h"
+#include "ParameterizationQuality.h"
+
+//#include "nvmesh/export/MeshExportOBJ.h"
+
+#include "nvmesh/halfedge/Mesh.h"
+#include "nvmesh/halfedge/Face.h"
+#include "nvmesh/halfedge/Vertex.h"
+
+#include "nvmesh/MeshBuilder.h"
+#include "nvmesh/MeshTopology.h"
+#include "nvmesh/param/Util.h"
+#include "nvmesh/geometry/Measurements.h"
+
+#include "nvmath/Vector.inl"
+#include "nvmath/Fitting.h"
+#include "nvmath/Box.inl"
+#include "nvmath/ProximityGrid.h"
+#include "nvmath/Morton.h"
+
+#include "nvcore/StrLib.h"
+#include "nvcore/Array.inl"
+#include "nvcore/HashMap.inl"
+
+using namespace nv;
+
+
+/// Ctor.
+Atlas::Atlas()
+{
+}
+
+// Dtor.
+Atlas::~Atlas()
+{
+    deleteAll(m_meshChartsArray);
+}
+
+uint Atlas::chartCount() const
+{
+    uint count = 0;
+    foreach(c, m_meshChartsArray) {
+        count += m_meshChartsArray[c]->chartCount();
+    }
+    return count;
+}
+
+const Chart * Atlas::chartAt(uint i) const
+{
+    foreach(c, m_meshChartsArray) {
+        uint count = m_meshChartsArray[c]->chartCount();
+
+        if (i < count) {
+            return m_meshChartsArray[c]->chartAt(i);
+        }
+
+        i -= count;
+    }
+
+    return NULL;
+}
+
+Chart * Atlas::chartAt(uint i) 
+{
+    foreach(c, m_meshChartsArray) {
+        uint count = m_meshChartsArray[c]->chartCount();
+
+        if (i < count) {
+            return m_meshChartsArray[c]->chartAt(i);
+        }
+
+        i -= count;
+    }
+
+    return NULL;
+}
+
+// Extract the charts and add to this atlas.
+void Atlas::addMeshCharts(MeshCharts * meshCharts)
+{
+    m_meshChartsArray.append(meshCharts);
+}
+
+void Atlas::extractCharts(const HalfEdge::Mesh * mesh)
+{
+    MeshCharts * meshCharts = new MeshCharts(mesh);
+    meshCharts->extractCharts();
+    addMeshCharts(meshCharts);
+}
+
+void Atlas::computeCharts(const HalfEdge::Mesh * mesh, const SegmentationSettings & settings, const Array<uint> & unchartedMaterialArray)
+{
+    MeshCharts * meshCharts = new MeshCharts(mesh);
+    meshCharts->computeCharts(settings, unchartedMaterialArray);
+    addMeshCharts(meshCharts);
+}
+
+
+
+
+#if 0
+
+/// Compute a seamless texture atlas.
+bool Atlas::computeSeamlessTextureAtlas(bool groupFaces/*= true*/, bool scaleTiles/*= false*/, uint w/*= 1024*/, uint h/* = 1024*/)
+{
+    // Implement seamless texture atlas similar to what ZBrush does. See also:
+    // "Meshed Atlases for Real-Time Procedural Solid Texturing"
+    // http://graphics.cs.uiuc.edu/~jch/papers/rtpst.pdf
+
+    // Other methods that we should experiment with:
+    // 
+    // Seamless Texture Atlases:
+    // http://www.cs.jhu.edu/~bpurnomo/STA/index.html
+    // 
+    // Rectangular Multi-Chart Geometry Images:
+    // http://graphics.cs.uiuc.edu/~jch/papers/rmcgi.pdf
+    // 
+    // Discrete differential geometry also provide a way of constructing  
+    // seamless quadrangulations as shown in:
+    // http://www.geometry.caltech.edu/pubs/TACD06.pdf
+    // 
+
+#pragma message(NV_FILE_LINE "TODO: Implement seamless texture atlas.")
+
+    if (groupFaces)
+    {
+        // @@ TODO.
+    }
+    else
+    {
+        // @@ Create one atlas per face.
+    }
+
+    if (scaleTiles)
+    {
+        // @@ TODO
+    }
+
+    /*
+    if (!isQuadMesh(m_mesh)) {
+        // Only handle quads for now.
+        return false;
+    }
+
+    // Each face is a chart.
+    const uint faceCount = m_mesh->faceCount();
+    m_chartArray.resize(faceCount);
+
+    for(uint f = 0; f < faceCount; f++) {
+        m_chartArray[f].faceArray.clear();
+        m_chartArray[f].faceArray.append(f);
+    }
+
+    // Map each face to a separate square.
+
+    // Determine face layout according to width and height.
+    float aspect = float(m_width) / float(m_height);
+
+    uint i = 2;
+    uint total = (m_width / (i+1)) * (m_height / (i+1));
+    while(total > faceCount) {
+        i *= 2;
+        total = (m_width / (i+1)) * (m_height / (i+1));
+    }
+
+    uint tileSize = i / 2;
+
+    int x = 0;
+    int y = 0;
+
+    m_result = new HalfEdge::Mesh();
+
+    // Once you have that it's just matter of traversing the faces.
+    for(uint f = 0; f < faceCount; f++) {
+        // Compute texture coordinates.
+        Vector2 tex[4];
+        tex[0] = Vector2(float(x), float(y));
+        tex[1] = Vector2(float(x+tileSize), float(y));
+        tex[2] = Vector2(float(x+tileSize), float(y+tileSize));
+        tex[3] = Vector2(float(x), float(y+tileSize));
+
+        Array<uint> indexArray(4);
+
+        const HalfEdge::Face * face = m_mesh->faceAt(f);
+
+        int i = 0;
+        for(HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance(), i++) {
+            const HalfEdge::Edge * edge = it.current();
+            const HalfEdge::Vertex * vertex = edge->from();
+
+            HalfEdge::Vertex * newVertex = m_result->addVertex(vertex->id(), vertex->pos());
+
+            newVertex->setTex(Vector3(tex[i], 0));
+            newVertex->setNor(vertex->nor());
+
+            indexArray.append(m_result->vertexCount() + 1);
+        }
+
+        m_result->addFace(indexArray);
+
+        // Move to the next tile.
+        x += tileSize + 1;
+        if (x + tileSize > m_width) {
+            x = 0;
+            y += tileSize + 1;
+        }
+    }
+    */
+
+    return false;
+}
+
+#endif
+
+
+void Atlas::parameterizeCharts()
+{
+    foreach(i, m_meshChartsArray) {
+        m_meshChartsArray[i]->parameterizeCharts();
+    }
+}
+
+
+float Atlas::packCharts(int quality, float texelsPerUnit, bool blockAlign, bool conservative)
+{
+    AtlasPacker packer(this);
+    packer.packCharts(quality, texelsPerUnit, blockAlign, conservative);
+    return packer.computeAtlasUtilization();
+}
+
+
+
+
+/// Ctor.
+MeshCharts::MeshCharts(const HalfEdge::Mesh * mesh) : m_mesh(mesh)
+{
+}
+
+// Dtor.
+MeshCharts::~MeshCharts()
+{
+    deleteAll(m_chartArray);
+}
+
+
+void MeshCharts::extractCharts()
+{
+    const uint faceCount = m_mesh->faceCount();
+
+    int first = 0;
+    Array<uint> queue(faceCount);
+
+    BitArray bitFlags(faceCount);
+    bitFlags.clearAll();
+
+    for (uint f = 0; f < faceCount; f++)
+    {
+        if (bitFlags.bitAt(f) == false)
+        {
+            // Start new patch. Reset queue.
+            first = 0;
+            queue.clear();
+            queue.append(f);
+            bitFlags.setBitAt(f);
+
+            while (first != queue.count())
+            {
+                const HalfEdge::Face * face = m_mesh->faceAt(queue[first]);
+
+                // Visit face neighbors of queue[first]
+                for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+                {
+                    const HalfEdge::Edge * edge = it.current();
+                    nvDebugCheck(edge->pair != NULL);
+
+                    if (!edge->isBoundary() && /*!edge->isSeam()*/ 
+                        //!(edge->from()->tex() != edge->pair()->to()->tex() || edge->to()->tex() != edge->pair()->from()->tex()))
+                        !(edge->from() != edge->pair->to() || edge->to() != edge->pair->from())) // Preserve existing seams (not just texture seams).
+                    {
+                        const HalfEdge::Face * neighborFace = edge->pair->face;
+                        nvDebugCheck(neighborFace != NULL);
+
+                        if (bitFlags.bitAt(neighborFace->id) == false)
+                        {
+                            queue.append(neighborFace->id);
+                            bitFlags.setBitAt(neighborFace->id);
+                        }
+                    }
+                }
+
+                first++;
+            }
+
+            Chart * chart = new Chart();
+            chart->build(m_mesh, queue);
+
+            m_chartArray.append(chart);
+        }
+    }
+}
+
+
+/*
+LSCM:
+- identify sharp features using local dihedral angles.
+- identify seed faces farthest from sharp features.
+- grow charts from these seeds.
+
+MCGIM:
+- phase 1: chart growth
+  - grow all charts simultaneously using dijkstra search on the dual graph of the mesh.
+  - graph edges are weighted based on planarity metric.
+  - metric uses distance to global chart normal.
+  - terminate when all faces have been assigned.
+- phase 2: seed computation:
+  - place new seed of the chart at the most interior face.
+  - most interior is evaluated using distance metric only.
+
+- method repeates the two phases, until the location of the seeds does not change.
+  - cycles are detected by recording all the previous seeds and chartification terminates.
+
+D-Charts:
+
+- Uniaxial conic metric:
+  - N_c = axis of the generalized cone that best fits the chart. (cone can a be cylinder or a plane).
+  - omega_c = angle between the face normals and the axis.
+  - Fitting error between chart C and tringle t: F(c,t) = (N_c*n_t - cos(omega_c))^2
+
+- Compactness metrics:
+  - Roundness:
+    - C(c,t) = pi * D(S_c,t)^2 / A_c
+    - S_c = chart seed.
+    - D(S_c,t) = length of the shortest path inside the chart betwen S_c and t.
+    - A_c = chart area.
+  - Straightness:
+    - P(c,t) = l_out(c,t) / l_in(c,t)
+    - l_out(c,t) = lenght of the edges not shared between C and t.
+    - l_in(c,t) = lenght of the edges shared between C and t.
+
+- Combined metric:
+  - Cost(c,t) = F(c,t)^alpha + C(c,t)^beta + P(c,t)^gamma
+  - alpha = 1, beta = 0.7, gamma = 0.5
+
+
+
+
+Our basic approach:
+- Just one iteration of k-means?
+- Avoid dijkstra by greedily growing charts until a threshold is met. Increase threshold and repeat until no faces left.
+- If distortion metric is too high, split chart, add two seeds.
+- If chart size is low, try removing chart.
+
+
+Postprocess:
+- If topology is not disk:
+  - Fill holes, if new faces fit proxy.
+  - Find best cut, otherwise.
+- After parameterization:
+  - If boundary self-intersects: 
+    - cut chart along the closest two diametral boundary vertices, repeat parametrization.
+    - what if the overlap is on an appendix? How do we find that out and cut appropiately?
+      - emphasize roundness metrics to prevent those cases.
+  - If interior self-overlaps: preserve boundary parameterization and use mean-value map.
+
+*/
+
+
+SegmentationSettings::SegmentationSettings()
+{
+    // Charts have no area or boundary limits right now.
+    maxChartArea = NV_FLOAT_MAX;
+    maxBoundaryLength = NV_FLOAT_MAX;
+
+    proxyFitMetricWeight = 1.0f;
+    roundnessMetricWeight = 0.1f;
+    straightnessMetricWeight = 0.25f;
+    normalSeamMetricWeight = 1.0f;
+    textureSeamMetricWeight = 0.1f;
+}
+
+
+
+void MeshCharts::computeCharts(const SegmentationSettings & settings, const Array<uint> & unchartedMaterialArray)
+{
+    Chart * vertexMap = NULL;
+    
+    if (unchartedMaterialArray.count() != 0) {
+        vertexMap = new Chart();
+        vertexMap->buildVertexMap(m_mesh, unchartedMaterialArray);
+
+        if (vertexMap->faceCount() == 0) {
+            delete vertexMap;
+            vertexMap = NULL;
+        }
+    }
+    
+
+    AtlasBuilder builder(m_mesh);
+
+    if (vertexMap != NULL) {
+        // Mark faces that do not need to be charted.
+        builder.markUnchartedFaces(vertexMap->faceArray());
+
+        m_chartArray.append(vertexMap);
+    }
+
+    if (builder.facesLeft != 0) {
+
+        // Tweak these values:
+        const float maxThreshold = 2;
+        const uint growFaceCount = 32;
+        const uint maxIterations = 4;
+        
+        builder.settings = settings;
+
+        //builder.settings.proxyFitMetricWeight *= 0.75; // relax proxy fit weight during initial seed placement.
+        //builder.settings.roundnessMetricWeight = 0;
+        //builder.settings.straightnessMetricWeight = 0;
+
+        // This seems a reasonable estimate.
+        uint maxSeedCount = max(6U, builder.facesLeft);
+
+        // Create initial charts greedely.
+        nvDebug("### Placing seeds\n");
+        builder.placeSeeds(maxThreshold, maxSeedCount);
+        nvDebug("###   Placed %d seeds (max = %d)\n", builder.chartCount(), maxSeedCount);
+
+        builder.updateProxies();
+
+        builder.mergeCharts();
+
+    #if 1
+        nvDebug("### Relocating seeds\n");
+        builder.relocateSeeds();
+
+        nvDebug("### Reset charts\n");
+        builder.resetCharts();
+
+        if (vertexMap != NULL) {
+            builder.markUnchartedFaces(vertexMap->faceArray());
+        }
+
+        builder.settings = settings;
+
+        nvDebug("### Growing charts\n");
+
+        // Restart process growing charts in parallel.
+        uint iteration = 0;
+        while (true)
+        {
+            if (!builder.growCharts(maxThreshold, growFaceCount))
+            {
+                nvDebug("### Can't grow anymore\n");
+
+                // If charts cannot grow more: fill holes, merge charts, relocate seeds and start new iteration.
+
+                nvDebug("### Filling holes\n");
+                builder.fillHoles(maxThreshold);
+                nvDebug("###   Using %d charts now\n", builder.chartCount());
+
+                builder.updateProxies();
+
+                nvDebug("### Merging charts\n");
+                builder.mergeCharts();
+                nvDebug("###   Using %d charts now\n", builder.chartCount());
+
+                nvDebug("### Reseeding\n");
+                if (!builder.relocateSeeds())
+                {
+                    nvDebug("### Cannot relocate seeds anymore\n");
+
+                    // Done!
+                    break;
+                }
+
+                if (iteration == maxIterations)
+                {
+                    nvDebug("### Reached iteration limit\n");
+                    break;
+                }
+                iteration++;
+
+                nvDebug("### Reset charts\n");
+                builder.resetCharts();
+
+                if (vertexMap != NULL) {
+                    builder.markUnchartedFaces(vertexMap->faceArray());
+                }
+
+                nvDebug("### Growing charts\n");
+            }
+        };
+    #endif
+
+        // Make sure no holes are left!
+        nvDebugCheck(builder.facesLeft == 0);
+
+        const uint chartCount = builder.chartArray.count();
+        for (uint i = 0; i < chartCount; i++)
+        {
+            Chart * chart = new Chart();
+            m_chartArray.append(chart);
+
+            chart->build(m_mesh, builder.chartFaces(i));
+        }
+    }
+
+
+    const uint chartCount = m_chartArray.count();
+
+    // Build face indices.
+    m_faceChart.resize(m_mesh->faceCount());
+    m_faceIndex.resize(m_mesh->faceCount());
+
+    for (uint i = 0; i < chartCount; i++)
+    {
+        const Chart * chart = m_chartArray[i];
+
+        const uint faceCount = chart->faceCount();
+        for (uint f = 0; f < faceCount; f++)
+        {
+            uint idx = chart->faceAt(f);
+            m_faceChart[idx] = i;
+            m_faceIndex[idx] = f;
+        }
+    }
+
+    // Build an exclusive prefix sum of the chart vertex counts.
+    m_chartVertexCountPrefixSum.resize(chartCount);
+    
+    if (chartCount > 0)
+    {
+        m_chartVertexCountPrefixSum[0] = 0;
+        
+        for (uint i = 1; i < chartCount; i++)
+        {
+            const Chart * chart = m_chartArray[i-1];
+            m_chartVertexCountPrefixSum[i] = m_chartVertexCountPrefixSum[i-1] + chart->vertexCount();
+        }
+
+        m_totalVertexCount = m_chartVertexCountPrefixSum[chartCount - 1] + m_chartArray[chartCount-1]->vertexCount();
+    }
+    else
+    {
+        m_totalVertexCount = 0;
+    }
+}
+
+
+void MeshCharts::parameterizeCharts()
+{
+    ParameterizationQuality globalParameterizationQuality;
+
+    // Parameterize the charts.
+    uint diskCount = 0;
+    const uint chartCount = m_chartArray.count();
+    for (uint i = 0; i < chartCount; i++)\
+    {
+        Chart * chart = m_chartArray[i];
+
+        bool isValid = false;
+
+        if (chart->isVertexMapped()) {
+            continue;
+        }
+
+        if (chart->isDisk())
+        {
+            diskCount++;
+
+            ParameterizationQuality chartParameterizationQuality;
+
+            if (chart->faceCount() == 1) {
+                computeSingleFaceMap(chart->unifiedMesh());
+
+                chartParameterizationQuality = ParameterizationQuality(chart->unifiedMesh());
+            }
+            else {
+                computeOrthogonalProjectionMap(chart->unifiedMesh());
+                ParameterizationQuality orthogonalQuality(chart->unifiedMesh());
+
+                computeLeastSquaresConformalMap(chart->unifiedMesh());
+                ParameterizationQuality lscmQuality(chart->unifiedMesh());
+                
+                // If the orthogonal projection produces better results, just use that.
+                // @@ It may be dangerous to do this, because isValid() does not detect self-overlaps.
+                // @@ Another problem is that with very thin patches with nearly zero parametric area, the results of our metric are not accurate.
+                /*if (orthogonalQuality.isValid() && orthogonalQuality.rmsStretchMetric() < lscmQuality.rmsStretchMetric()) {
+                    computeOrthogonalProjectionMap(chart->unifiedMesh());
+                    chartParameterizationQuality = orthogonalQuality;
+                }
+                else*/ {
+                    chartParameterizationQuality = lscmQuality;
+                }
+
+                // If conformal map failed, 
+
+                // @@ Experiment with other parameterization methods.
+                //computeCircularBoundaryMap(chart->unifiedMesh());
+                //computeConformalMap(chart->unifiedMesh());
+                //computeNaturalConformalMap(chart->unifiedMesh());
+                //computeGuidanceGradientMap(chart->unifiedMesh());
+            }
+
+            //ParameterizationQuality chartParameterizationQuality(chart->unifiedMesh());
+
+            isValid = chartParameterizationQuality.isValid();
+
+            if (!isValid)
+            {
+                nvDebug("*** Invalid parameterization.\n");
+#if 0
+                // Dump mesh to inspect problem:
+                static int pieceCount = 0;
+            
+                StringBuilder fileName;
+                fileName.format("invalid_chart_%d.obj", pieceCount++);
+                exportMesh(chart->unifiedMesh(), fileName.str()); 
+#endif
+            }
+
+            // @@ Check that parameterization quality is above a certain threshold.
+
+            // @@ Detect boundary self-intersections.
+
+            globalParameterizationQuality += chartParameterizationQuality;
+        }
+
+        if (!isValid)
+        {
+            //nvDebugBreak();
+            // @@ Run the builder again, but only on this chart.
+            //AtlasBuilder builder(chart->chartMesh());
+        }
+
+        // Transfer parameterization from unified mesh to chart mesh.
+        chart->transferParameterization();
+
+    }
+
+    nvDebug("  Parameterized %d/%d charts.\n", diskCount, chartCount);
+    nvDebug("  RMS stretch metric: %f\n", globalParameterizationQuality.rmsStretchMetric());
+    nvDebug("  MAX stretch metric: %f\n", globalParameterizationQuality.maxStretchMetric());
+    nvDebug("  RMS conformal metric: %f\n", globalParameterizationQuality.rmsConformalMetric());
+    nvDebug("  RMS authalic metric: %f\n", globalParameterizationQuality.maxAuthalicMetric());
+}
+
+
+
+Chart::Chart() : m_chartMesh(NULL), m_unifiedMesh(NULL), m_isDisk(false), m_isVertexMapped(false)
+{
+}
+
+void Chart::build(const HalfEdge::Mesh * originalMesh, const Array<uint> & faceArray)
+{
+    // Copy face indices.
+    m_faceArray = faceArray;
+
+    const uint meshVertexCount = originalMesh->vertexCount();
+
+    m_chartMesh = new HalfEdge::Mesh();
+    m_unifiedMesh = new HalfEdge::Mesh();
+
+    Array<uint> chartMeshIndices;
+    chartMeshIndices.resize(meshVertexCount, ~0);
+
+    Array<uint> unifiedMeshIndices;
+    unifiedMeshIndices.resize(meshVertexCount, ~0);
+
+    // Add vertices.
+    const uint faceCount = faceArray.count();
+    for (uint f = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = originalMesh->faceAt(faceArray[f]);
+        nvDebugCheck(face != NULL);
+
+        for(HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+        {
+            const HalfEdge::Vertex * vertex = it.current()->vertex;
+            const HalfEdge::Vertex * unifiedVertex = vertex->firstColocal();
+
+            if (unifiedMeshIndices[unifiedVertex->id] == ~0)
+            {
+                unifiedMeshIndices[unifiedVertex->id] = m_unifiedMesh->vertexCount();
+
+                nvDebugCheck(vertex->pos == unifiedVertex->pos);
+                m_unifiedMesh->addVertex(vertex->pos);
+            }
+
+            if (chartMeshIndices[vertex->id] == ~0)
+            {
+                chartMeshIndices[vertex->id] = m_chartMesh->vertexCount();
+                m_chartToOriginalMap.append(vertex->id);
+                m_chartToUnifiedMap.append(unifiedMeshIndices[unifiedVertex->id]);
+
+                HalfEdge::Vertex * v = m_chartMesh->addVertex(vertex->pos);
+                v->nor = vertex->nor;
+                v->tex = vertex->tex;
+            }
+        }
+    }
+
+    // This is ignoring the canonical map:
+    // - Is it really necessary to link colocals?
+
+    m_chartMesh->linkColocals();    
+    //m_unifiedMesh->linkColocals();  // Not strictly necessary, no colocals in the unified mesh. # Wrong.
+
+    // This check is not valid anymore, if the original mesh vertices were linked with a canonical map, then it might have
+    // some colocal vertices that were unlinked. So, the unified mesh might have some duplicate vertices, because firstColocal()
+    // is not guaranteed to return the same vertex for two colocal vertices.
+    //nvCheck(m_chartMesh->colocalVertexCount() == m_unifiedMesh->vertexCount());
+
+    // Is that OK? What happens in meshes were that happens? Does anything break? Apparently not...
+    
+
+
+    Array<uint> faceIndices(7);
+
+    // Add faces.
+    for (uint f = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = originalMesh->faceAt(faceArray[f]);
+        nvDebugCheck(face != NULL);
+
+        faceIndices.clear();
+
+        for(HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+        {
+            const HalfEdge::Vertex * vertex = it.current()->vertex;
+            nvDebugCheck(vertex != NULL);
+
+            faceIndices.append(chartMeshIndices[vertex->id]);
+        }
+
+        m_chartMesh->addFace(faceIndices);
+
+        faceIndices.clear();
+
+        for(HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+        {
+            const HalfEdge::Vertex * vertex = it.current()->vertex;
+            nvDebugCheck(vertex != NULL);
+
+            vertex = vertex->firstColocal();
+
+            faceIndices.append(unifiedMeshIndices[vertex->id]);
+        }
+
+        m_unifiedMesh->addFace(faceIndices);
+    }
+
+    m_chartMesh->linkBoundary();
+    m_unifiedMesh->linkBoundary();
+
+    //exportMesh(m_unifiedMesh.ptr(), "debug_input.obj");
+
+    if (m_unifiedMesh->splitBoundaryEdges()) {
+        m_unifiedMesh = unifyVertices(m_unifiedMesh.ptr());
+    }
+
+    //exportMesh(m_unifiedMesh.ptr(), "debug_split.obj");
+
+    // Closing the holes is not always the best solution and does not fix all the problems.
+    // We need to do some analysis of the holes and the genus to:
+    // - Find cuts that reduce genus.
+    // - Find cuts to connect holes.
+    // - Use minimal spanning trees or seamster.
+    if (!closeHoles()) {
+        /*static int pieceCount = 0;
+        StringBuilder fileName;
+        fileName.format("debug_hole_%d.obj", pieceCount++);
+        exportMesh(m_unifiedMesh.ptr(), fileName.str());*/
+    }
+
+    m_unifiedMesh = triangulate(m_unifiedMesh.ptr());
+    
+    //exportMesh(m_unifiedMesh.ptr(), "debug_triangulated.obj");
+
+
+    // Analyze chart topology.
+    MeshTopology topology(m_unifiedMesh.ptr());
+    m_isDisk = topology.isDisk();
+
+    // This is sometimes failing, when triangulate fails to add a triangle, it generates a hole in the mesh.
+    //nvDebugCheck(m_isDisk);
+
+    /*if (!m_isDisk) {
+        static int pieceCount = 0;
+        StringBuilder fileName;
+        fileName.format("debug_hole_%d.obj", pieceCount++);
+        exportMesh(m_unifiedMesh.ptr(), fileName.str());
+    }*/
+
+
+#if 0
+    if (!m_isDisk) {
+        nvDebugBreak();
+
+        static int pieceCount = 0;
+        
+        StringBuilder fileName;
+        fileName.format("debug_nodisk_%d.obj", pieceCount++);
+        exportMesh(m_chartMesh.ptr(), fileName.str()); 
+    }
+#endif
+
+}
+
+
+void Chart::buildVertexMap(const HalfEdge::Mesh * originalMesh, const Array<uint> & unchartedMaterialArray)
+{
+    nvCheck(m_chartMesh == NULL && m_unifiedMesh == NULL);
+
+    m_isVertexMapped = true;
+
+    // Build face indices.
+    m_faceArray.clear();
+
+    const uint meshFaceCount = originalMesh->faceCount();
+    for (uint f = 0; f < meshFaceCount; f++) {
+        const HalfEdge::Face * face = originalMesh->faceAt(f);
+
+        if (unchartedMaterialArray.contains(face->material)) {
+            m_faceArray.append(f);
+        }
+    }
+
+    const uint faceCount = m_faceArray.count();
+
+    if (faceCount == 0) {
+        return;
+    }
+
+
+    // @@ The chartMesh construction is basically the same as with regular charts, don't duplicate!
+
+    const uint meshVertexCount = originalMesh->vertexCount();
+
+    m_chartMesh = new HalfEdge::Mesh();
+
+    Array<uint> chartMeshIndices;
+    chartMeshIndices.resize(meshVertexCount, ~0);
+
+    // Vertex map mesh only has disconnected vertices.
+    for (uint f = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = originalMesh->faceAt(m_faceArray[f]);
+        nvDebugCheck(face != NULL);
+
+        for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+        {
+            const HalfEdge::Vertex * vertex = it.current()->vertex;
+
+            if (chartMeshIndices[vertex->id] == ~0)
+            {
+                chartMeshIndices[vertex->id] = m_chartMesh->vertexCount();
+                m_chartToOriginalMap.append(vertex->id);
+
+                HalfEdge::Vertex * v = m_chartMesh->addVertex(vertex->pos);
+                v->nor = vertex->nor;
+                v->tex = vertex->tex; // @@ Not necessary.
+            }
+        }
+    }
+
+    // @@ Link colocals using the original mesh canonical map? Build canonical map on the fly? Do we need to link colocals at all for this?
+    //m_chartMesh->linkColocals();
+
+    Array<uint> faceIndices(7);
+
+    // Add faces.
+    for (uint f = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = originalMesh->faceAt(m_faceArray[f]);
+        nvDebugCheck(face != NULL);
+
+        faceIndices.clear();
+
+        for(HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+        {
+            const HalfEdge::Vertex * vertex = it.current()->vertex;
+            nvDebugCheck(vertex != NULL);
+            nvDebugCheck(chartMeshIndices[vertex->id] != ~0);
+
+            faceIndices.append(chartMeshIndices[vertex->id]);
+        }
+
+        HalfEdge::Face * new_face = m_chartMesh->addFace(faceIndices);
+        nvDebugCheck(new_face != NULL);
+    }
+
+    m_chartMesh->linkBoundary();
+
+
+    const uint chartVertexCount = m_chartMesh->vertexCount();
+
+    Box bounds;
+    bounds.clearBounds();
+
+    for (uint i = 0; i < chartVertexCount; i++) {
+        HalfEdge::Vertex * vertex = m_chartMesh->vertexAt(i);
+        bounds.addPointToBounds(vertex->pos);
+    }
+
+    ProximityGrid grid;
+    grid.init(bounds, chartVertexCount);
+
+    for (uint i = 0; i < chartVertexCount; i++) {
+        HalfEdge::Vertex * vertex = m_chartMesh->vertexAt(i);
+        grid.add(vertex->pos, i);
+    }
+
+
+#if 0
+    // Arrange vertices in a rectangle.
+    vertexMapWidth = ftoi_ceil(sqrtf(float(chartVertexCount)));
+    vertexMapHeight = (chartVertexCount + vertexMapWidth - 1) / vertexMapWidth;
+    nvDebugCheck(vertexMapWidth >= vertexMapHeight);
+
+    int x = 0, y = 0;
+    for (uint i = 0; i < chartVertexCount; i++) {
+        HalfEdge::Vertex * vertex = m_chartMesh->vertexAt(i);
+
+        vertex->tex.x = float(x);
+        vertex->tex.y = float(y);
+
+        x++;
+        if (x == vertexMapWidth) {
+            x = 0;
+            y++;
+            nvCheck(y < vertexMapHeight);
+        }
+    }
+
+#elif 0
+    // Arrange vertices in a rectangle, traversing grid in 3D morton order and laying them down in 2D morton order.
+    vertexMapWidth = ftoi_ceil(sqrtf(float(chartVertexCount)));
+    vertexMapHeight = (chartVertexCount + vertexMapWidth - 1) / vertexMapWidth;
+    nvDebugCheck(vertexMapWidth >= vertexMapHeight);
+
+    int n = 0;
+    uint32 texelCode = 0;
+
+    uint cellsVisited = 0;
+
+    const uint32 cellCodeCount = grid.mortonCount();
+    for (uint32 cellCode = 0; cellCode < cellCodeCount; cellCode++) {
+        int cell = grid.mortonIndex(cellCode);
+        if (cell < 0) continue;
+
+        cellsVisited++;
+
+        const Array<uint> & indexArray = grid.cellArray[cell].indexArray;
+
+        foreach(i, indexArray) {
+            uint idx = indexArray[i];
+            HalfEdge::Vertex * vertex = m_chartMesh->vertexAt(idx);
+
+            //vertex->tex.x = float(n % rectangleWidth) + 0.5f;
+            //vertex->tex.y = float(n / rectangleWidth) + 0.5f;
+
+            // Lay down the points in z order too.
+            uint x, y;
+            do {
+                x = decodeMorton2X(texelCode);
+                y = decodeMorton2Y(texelCode);
+                texelCode++;
+            } while (x >= U32(vertexMapWidth) || y >= U32(vertexMapHeight));
+            
+            vertex->tex.x = float(x);
+            vertex->tex.y = float(y);
+
+            n++;
+        }
+    }
+
+    nvDebugCheck(cellsVisited == grid.cellArray.count());
+    nvDebugCheck(n == chartVertexCount);
+
+#else
+
+    uint texelCount = 0;
+
+    const float positionThreshold = 0.01f;
+    const float normalThreshold = 0.01f;
+
+    uint verticesVisited = 0;
+    uint cellsVisited = 0;
+
+    Array<int> vertexIndexArray;
+    vertexIndexArray.resize(chartVertexCount, -1); // Init all indices to -1.
+
+    // Traverse vertices in morton order. @@ It may be more interesting to sort them based on orientation.
+    const uint cellCodeCount = grid.mortonCount();
+    for (uint cellCode = 0; cellCode < cellCodeCount; cellCode++) {
+        int cell = grid.mortonIndex(cellCode);
+        if (cell < 0) continue;
+
+        cellsVisited++;
+
+        const Array<uint> & indexArray = grid.cellArray[cell].indexArray;
+
+        foreach(i, indexArray) {
+            uint idx = indexArray[i];
+            HalfEdge::Vertex * vertex = m_chartMesh->vertexAt(idx);
+
+            nvDebugCheck(vertexIndexArray[idx] == -1);
+
+            Array<uint> neighbors;
+            grid.gather(vertex->pos, positionThreshold, /*ref*/neighbors);
+
+            // Compare against all nearby vertices, cluster greedily.
+            foreach(j, neighbors) {
+                uint otherIdx = neighbors[j];
+
+                if (vertexIndexArray[otherIdx] != -1) {
+                    HalfEdge::Vertex * otherVertex = m_chartMesh->vertexAt(otherIdx);
+
+                    if (distance(vertex->pos, otherVertex->pos) < positionThreshold &&
+                        distance(vertex->nor, otherVertex->nor) < normalThreshold) 
+                    {
+                        vertexIndexArray[idx] = vertexIndexArray[otherIdx];
+                        break;
+                    }
+                }
+            }
+
+            // If index not assigned, assign new one.
+            if (vertexIndexArray[idx] == -1) {
+                vertexIndexArray[idx] = texelCount++;
+            }
+
+            verticesVisited++;
+        }
+    }
+
+    nvDebugCheck(cellsVisited == grid.cellArray.count());
+    nvDebugCheck(verticesVisited == chartVertexCount);
+
+    vertexMapWidth = ftoi_ceil(sqrtf(float(texelCount)));
+    vertexMapWidth = (vertexMapWidth + 3) & ~3;                             // Width aligned to 4.
+    vertexMapHeight = vertexMapWidth == 0 ? 0 : (texelCount + vertexMapWidth - 1) / vertexMapWidth;
+    //vertexMapHeight = (vertexMapHeight + 3) & ~3;                           // Height aligned to 4.
+    nvDebugCheck(vertexMapWidth >= vertexMapHeight);
+
+    nvDebug("Reduced vertex count from %d to %d.\n", chartVertexCount, texelCount);
+
+#if 0
+    // This lays down the clustered vertices linearly.
+    for (uint i = 0; i < chartVertexCount; i++) {
+        HalfEdge::Vertex * vertex = m_chartMesh->vertexAt(i);
+
+        int idx = vertexIndexArray[i];
+
+        vertex->tex.x = float(idx % vertexMapWidth);
+        vertex->tex.y = float(idx / vertexMapWidth);
+    }
+#else
+    // Lay down the clustered vertices in morton order.
+
+    Array<uint> texelCodes;
+    texelCodes.resize(texelCount);
+
+    // For each texel, assign one morton code.
+    uint texelCode = 0;
+    for (uint i = 0; i < texelCount; i++) {
+        uint x, y;
+        do {
+            x = decodeMorton2X(texelCode);
+            y = decodeMorton2Y(texelCode);
+            texelCode++;
+        } while (x >= U32(vertexMapWidth) || y >= U32(vertexMapHeight));
+
+        texelCodes[i] = texelCode - 1;
+    }
+
+    for (uint i = 0; i < chartVertexCount; i++) {
+        HalfEdge::Vertex * vertex = m_chartMesh->vertexAt(i);
+
+        int idx = vertexIndexArray[i];
+        if (idx != -1) {
+            uint texelCode = texelCodes[idx];
+            uint x = decodeMorton2X(texelCode);
+            uint y = decodeMorton2Y(texelCode);
+
+            vertex->tex.x = float(x);
+            vertex->tex.y = float(y);
+        }
+    }
+
+#endif
+   
+#endif
+
+}
+
+
+
+static void getBoundaryEdges(HalfEdge::Mesh * mesh, Array<HalfEdge::Edge *> & boundaryEdges)
+{
+    nvDebugCheck(mesh != NULL);
+
+    const uint edgeCount = mesh->edgeCount();
+
+    BitArray bitFlags(edgeCount);
+    bitFlags.clearAll();
+
+    boundaryEdges.clear();
+
+    // Search for boundary edges. Mark all the edges that belong to the same boundary.
+    for (uint e = 0; e < edgeCount; e++)
+    {
+        HalfEdge::Edge * startEdge = mesh->edgeAt(e);
+
+        if (startEdge != NULL && startEdge->isBoundary() && bitFlags.bitAt(e) == false)
+        {
+            nvDebugCheck(startEdge->face != NULL);
+            nvDebugCheck(startEdge->pair->face == NULL);
+
+            startEdge = startEdge->pair;
+
+            const HalfEdge::Edge * edge = startEdge;
+            do {
+                nvDebugCheck(edge->face == NULL);
+                nvDebugCheck(bitFlags.bitAt(edge->id/2) == false);
+
+                bitFlags.setBitAt(edge->id / 2);
+                edge = edge->next;
+            } while(startEdge != edge);
+
+            boundaryEdges.append(startEdge);
+        }
+    }
+}
+
+
+bool Chart::closeLoop(uint start, const Array<HalfEdge::Edge *> & loop)
+{
+    const uint vertexCount = loop.count() - start;
+
+    nvDebugCheck(vertexCount >= 3);
+    if (vertexCount < 3) return false;
+
+    nvDebugCheck(loop[start]->vertex->isColocal(loop[start+vertexCount-1]->to()));
+
+    // If the hole is planar, then we add a single face that will be properly triangulated later.
+    // If the hole is not planar, we add a triangle fan with a vertex at the hole centroid.
+    // This is still a bit of a hack. There surely are better hole filling algorithms out there.
+
+    Array<Vector3> points;
+    points.resize(vertexCount);
+    for (uint i = 0; i < vertexCount; i++) {
+        points[i] = loop[start+i]->vertex->pos;
+    }
+
+    bool isPlanar = Fit::isPlanar(vertexCount, points.buffer());
+
+    if (isPlanar) {
+        // Add face and connect edges.
+        HalfEdge::Face * face = m_unifiedMesh->addFace();
+        for (uint i = 0; i < vertexCount; i++) {
+            HalfEdge::Edge * edge = loop[start + i];
+            
+            edge->face = face;
+            edge->setNext(loop[start + (i + 1) % vertexCount]);
+        }
+        face->edge = loop[start];
+
+        nvDebugCheck(face->isValid());
+    }
+    else {
+        // If the polygon is not planar, we just cross our fingers, and hope this will work:
+
+        // Compute boundary centroid:
+        Vector3 centroidPos(0);
+
+        for (uint i = 0; i < vertexCount; i++) {
+            centroidPos += points[i];
+        }
+
+        centroidPos *= (1.0f / vertexCount);
+
+        HalfEdge::Vertex * centroid = m_unifiedMesh->addVertex(centroidPos);
+
+        // Add one pair of edges for each boundary vertex.
+        for (uint j = vertexCount-1, i = 0; i < vertexCount; j = i++) {
+            HalfEdge::Face * face = m_unifiedMesh->addFace(centroid->id, loop[start+j]->vertex->id, loop[start+i]->vertex->id);
+            nvDebugCheck(face != NULL);
+        }
+    }
+
+    return true;
+}
+
+
+bool Chart::closeHoles()
+{
+    nvDebugCheck(!m_isVertexMapped);
+
+    Array<HalfEdge::Edge *> boundaryEdges;
+    getBoundaryEdges(m_unifiedMesh.ptr(), boundaryEdges);
+
+    uint boundaryCount = boundaryEdges.count();
+    if (boundaryCount <= 1)
+    {
+        // Nothing to close.
+        return true;
+    }
+
+    // Compute lengths and areas.
+    Array<float> boundaryLengths;
+    //Array<Vector3> boundaryCentroids;
+
+    for (uint i = 0; i < boundaryCount; i++)
+    {
+        const HalfEdge::Edge * startEdge = boundaryEdges[i];
+        nvCheck(startEdge->face == NULL);
+
+        //float boundaryEdgeCount = 0;
+        float boundaryLength = 0.0f;
+        //Vector3 boundaryCentroid(zero);
+
+        const HalfEdge::Edge * edge = startEdge;
+        do {
+            Vector3 t0 = edge->from()->pos;
+            Vector3 t1 = edge->to()->pos;
+
+            //boundaryEdgeCount++;
+            boundaryLength += length(t1 - t0);
+            //boundaryCentroid += edge->vertex()->pos;
+
+            edge = edge->next;
+        } while(edge != startEdge);
+
+        boundaryLengths.append(boundaryLength);
+        //boundaryCentroids.append(boundaryCentroid / boundaryEdgeCount);
+    }
+
+
+    // Find disk boundary.
+    uint diskBoundary = 0;
+    float maxLength = boundaryLengths[0];
+
+    for (uint i = 1; i < boundaryCount; i++)
+    {
+        if (boundaryLengths[i] > maxLength)
+        {
+            maxLength = boundaryLengths[i];
+            diskBoundary = i;
+        }
+    }
+
+
+    // Sew holes.
+    /*for (uint i = 0; i < boundaryCount; i++)
+    {
+        if (diskBoundary == i)
+        {
+            // Skip disk boundary.
+            continue;
+        }
+
+        HalfEdge::Edge * startEdge = boundaryEdges[i];
+        nvCheck(startEdge->face() == NULL);
+
+        boundaryEdges[i] = m_unifiedMesh->sewBoundary(startEdge);
+    }
+
+    exportMesh(m_unifiedMesh.ptr(), "debug_sewn.obj");*/
+
+    //bool hasNewHoles = false;
+
+    // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+    // @@ Close loop is wrong, after closing a loop, we do not only have to add the face, but make sure that every edge in he loop is pointing to the right place.
+
+    // Close holes.
+    for (uint i = 0; i < boundaryCount; i++)
+    {
+        if (diskBoundary == i)
+        {
+            // Skip disk boundary.
+            continue;
+        }
+
+        HalfEdge::Edge * startEdge = boundaryEdges[i];
+        nvDebugCheck(startEdge != NULL);
+        nvDebugCheck(startEdge->face == NULL);
+
+#if 1
+        Array<HalfEdge::Vertex *> vertexLoop;
+        Array<HalfEdge::Edge *> edgeLoop;
+
+        HalfEdge::Edge * edge = startEdge;
+        do {
+            HalfEdge::Vertex * vertex = edge->next->vertex; // edge->to()
+
+            uint i;
+            for (i = 0; i < vertexLoop.count(); i++) {
+                if (vertex->isColocal(vertexLoop[i])) {
+                    break;
+                }
+            }
+            
+            bool isCrossing = (i != vertexLoop.count());
+
+            if (isCrossing) {
+
+                HalfEdge::Edge * prev = edgeLoop[i];    // Previous edge before the loop.
+                HalfEdge::Edge * next = edge->next;   // Next edge after the loop.
+
+                nvDebugCheck(prev->to()->isColocal(next->from()));
+
+                // Close loop.
+                edgeLoop.append(edge);
+                closeLoop(i+1, edgeLoop);
+
+                // Link boundary loop.
+                prev->setNext(next);
+                vertex->setEdge(next);
+
+                // Start over again.
+                vertexLoop.clear();
+                edgeLoop.clear();
+                
+                edge = startEdge;
+                vertex = edge->to();
+            }
+
+            vertexLoop.append(vertex);
+            edgeLoop.append(edge);
+
+            edge = edge->next;
+        } while(edge != startEdge);
+
+        closeLoop(0, edgeLoop);
+#endif
+
+        /*
+
+        // Add face and connect boundary edges.
+        HalfEdge::Face * face = m_unifiedMesh->addFace();
+        face->setEdge(startEdge);
+
+        HalfEdge::Edge * edge = startEdge;
+        do {
+            edge->setFace(face);
+
+            edge = edge->next();
+        } while(edge != startEdge);
+
+        */
+
+
+        /*
+        uint edgeCount = 0;
+        HalfEdge::Edge * edge = startEdge;
+        do {
+            edgeCount++;
+            edge = edge->next();
+        } while(edge != startEdge);
+
+
+
+        // Count edges in this boundary.
+        uint edgeCount = 0;
+        HalfEdge::Edge * edge = startEdge;
+        do {
+            edgeCount++;
+            edge = edge->next();
+        } while(edge != startEdge);
+
+        // Trivial hole, fill with one triangle. This actually works for all convex boundaries with non colinear vertices.
+        if (edgeCount == 3) {
+            // Add face and connect boundary edges.
+            HalfEdge::Face * face = m_unifiedMesh->addFace();
+            face->setEdge(startEdge);
+
+            edge = startEdge;
+            do {
+                edge->setFace(face);
+
+                edge = edge->next();
+            } while(edge != startEdge);
+
+            // @@ Implement the above using addFace, it should now work with existing edges, as long as their face pointers is zero.
+
+        }
+        else {
+            // Ideally we should:
+            // - compute best fit plane of boundary vertices.
+            // - project boundary polygon onto plane.
+            // - triangulate boundary polygon.
+            // - add faces of the resulting triangulation.
+
+            // I don't have a good triangulator available. A more simple solution that works in more (but not all) cases:
+            // - compute boundary centroid.
+            // - add vertex centroid.
+            // - connect centroid vertex with boundary vertices.
+            // - connect radial edges with boundary edges.
+
+            // This should work for non-convex boundaries with colinear vertices as long as the kernel of the polygon is not empty.
+
+            // Compute boundary centroid:
+            Vector3 centroid_pos(0);
+            Vector2 centroid_tex(0);
+
+            HalfEdge::Edge * edge = startEdge;
+            do {
+                centroid_pos += edge->vertex()->pos;
+                centroid_tex += edge->vertex()->tex;
+                edge = edge->next();
+            } while(edge != startEdge);
+
+            centroid_pos *= (1.0f / edgeCount);
+            centroid_tex *= (1.0f / edgeCount);
+
+            HalfEdge::Vertex * centroid = m_unifiedMesh->addVertex(centroid_pos);
+            centroid->tex = centroid_tex;
+
+            // Add one pair of edges for each boundary vertex.
+            edge = startEdge;
+            do {
+                HalfEdge::Edge * next = edge->next();
+
+                nvCheck(edge->face() == NULL);
+                HalfEdge::Face * face = m_unifiedMesh->addFace(centroid->id(), edge->from()->id(), edge->to()->id());
+                
+                if (face != NULL) {
+                    nvCheck(edge->face() == face);
+                }
+                else {
+                    hasNewHoles = true;
+                }
+
+                edge = next;
+            } while(edge != startEdge);
+        }
+        */
+    }
+
+    /*nvDebugCheck(!hasNewHoles);
+
+    if (hasNewHoles) {
+        // Link boundary again, in case closeHoles created new holes!
+        m_unifiedMesh->linkBoundary();
+    }*/
+
+    // Because some algorithms do not expect sparse edge buffers.
+    //m_unifiedMesh->compactEdges();
+
+    // In case we messed up:
+    //m_unifiedMesh->linkBoundary();
+
+    getBoundaryEdges(m_unifiedMesh.ptr(), boundaryEdges);
+
+    boundaryCount = boundaryEdges.count();
+    nvDebugCheck(boundaryCount == 1);
+
+    //exportMesh(m_unifiedMesh.ptr(), "debug_hole_filled.obj");
+
+    return boundaryCount == 1;
+}
+
+
+// Transfer parameterization from unified mesh to chart mesh.
+void Chart::transferParameterization() {
+    nvDebugCheck(!m_isVertexMapped);
+
+    uint vertexCount = m_chartMesh->vertexCount();
+    for (uint v = 0; v < vertexCount; v++) {
+        HalfEdge::Vertex * vertex = m_chartMesh->vertexAt(v);
+        HalfEdge::Vertex * unifiedVertex = m_unifiedMesh->vertexAt(mapChartVertexToUnifiedVertex(v));
+        vertex->tex = unifiedVertex->tex;
+    }
+}
+
+float Chart::computeSurfaceArea() const {
+    return nv::computeSurfaceArea(m_chartMesh.ptr()) * scale;
+}
+
+float Chart::computeParametricArea() const {
+    // This only makes sense in parameterized meshes.
+    nvDebugCheck(m_isDisk);            
+    nvDebugCheck(!m_isVertexMapped);
+
+    return nv::computeParametricArea(m_chartMesh.ptr());
+}
+
+Vector2 Chart::computeParametricBounds() const {
+    // This only makes sense in parameterized meshes.
+    nvDebugCheck(m_isDisk);
+    nvDebugCheck(!m_isVertexMapped);
+
+    Box bounds;
+    bounds.clearBounds();
+
+    uint vertexCount = m_chartMesh->vertexCount();
+    for (uint v = 0; v < vertexCount; v++) {
+        HalfEdge::Vertex * vertex = m_chartMesh->vertexAt(v);
+        bounds.addPointToBounds(Vector3(vertex->tex, 0));
+    }
+
+    return bounds.extents().xy();
+}
diff --git a/thirdparty/thekla_atlas/nvmesh/param/Atlas.h b/thirdparty/thekla_atlas/nvmesh/param/Atlas.h
new file mode 100644
index 0000000000..8b478207e3
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/Atlas.h
@@ -0,0 +1,183 @@
+// Copyright NVIDIA Corporation 2006 -- Ignacio Castano <icastano@nvidia.com>
+
+#pragma once
+#ifndef NV_MESH_ATLAS_H
+#define NV_MESH_ATLAS_H
+
+#include "nvcore/Array.h"
+#include "nvcore/Ptr.h"
+#include "nvmath/Vector.h"
+#include "nvmesh/nvmesh.h"
+#include "nvmesh/halfedge/Mesh.h"
+
+
+namespace nv
+{
+    namespace HalfEdge { class Mesh; }
+
+    class Chart;
+    class MeshCharts;
+    class VertexMap;
+
+    struct SegmentationSettings
+    {
+        SegmentationSettings();
+
+        float maxChartArea;
+        float maxBoundaryLength;
+
+        float proxyFitMetricWeight;
+        float roundnessMetricWeight;
+        float straightnessMetricWeight;
+        float normalSeamMetricWeight;
+        float textureSeamMetricWeight;
+    };
+
+
+    /// An atlas is a set of charts.
+    class Atlas
+    {
+    public:
+
+        Atlas();
+        ~Atlas();
+
+        uint meshCount() const { return m_meshChartsArray.count(); }
+        const MeshCharts * meshAt(uint i) const { return m_meshChartsArray[i]; }
+        MeshCharts * meshAt(uint i) { return m_meshChartsArray[i]; }
+
+        uint chartCount() const;
+        const Chart * chartAt(uint i) const;
+        Chart * chartAt(uint i);
+
+        // Add mesh charts and takes ownership.
+        void addMeshCharts(MeshCharts * meshCharts);
+
+        void extractCharts(const HalfEdge::Mesh * mesh);
+        void computeCharts(const HalfEdge::Mesh * mesh, const SegmentationSettings & settings, const Array<uint> & unchartedMaterialArray);
+
+
+        // Compute a trivial seamless texture similar to ZBrush.
+        //bool computeSeamlessTextureAtlas(bool groupFaces = true, bool scaleTiles = false, uint w = 1024, uint h = 1024);
+
+        void parameterizeCharts();
+
+        // Pack charts in the smallest possible rectangle.
+        float packCharts(int quality, float texelArea, bool blockAlign, bool conservative);
+
+    private:
+
+        Array<MeshCharts *> m_meshChartsArray;
+
+    };
+
+
+    // Set of charts corresponding to a single mesh.
+    class MeshCharts
+    {
+    public:
+        MeshCharts(const HalfEdge::Mesh * mesh);
+        ~MeshCharts();
+
+        uint chartCount() const { return m_chartArray.count(); }
+        uint vertexCount () const { return m_totalVertexCount; }
+
+        const Chart * chartAt(uint i) const { return m_chartArray[i]; }
+        Chart * chartAt(uint i) { return m_chartArray[i]; }
+
+        void computeVertexMap(const Array<uint> & unchartedMaterialArray);
+
+        // Extract the charts of the input mesh.
+        void extractCharts();
+
+        // Compute charts using a simple segmentation algorithm.
+        void computeCharts(const SegmentationSettings & settings, const Array<uint> & unchartedMaterialArray);
+
+        void parameterizeCharts();
+
+        uint faceChartAt(uint i) const { return m_faceChart[i]; }
+        uint faceIndexWithinChartAt(uint i) const { return m_faceIndex[i]; }
+
+        uint vertexCountBeforeChartAt(uint i) const { return m_chartVertexCountPrefixSum[i]; }
+
+    private:
+
+        const HalfEdge::Mesh * m_mesh;
+
+        Array<Chart *> m_chartArray;
+        
+        Array<uint> m_chartVertexCountPrefixSum;
+        uint m_totalVertexCount;
+
+        Array<uint> m_faceChart; // the chart of every face of the input mesh.
+        Array<uint> m_faceIndex; // the index within the chart for every face of the input mesh.
+    };
+
+
+    /// A chart is a connected set of faces with a certain topology (usually a disk).
+    class Chart
+    {
+    public:
+
+        Chart();
+
+        void build(const HalfEdge::Mesh * originalMesh, const Array<uint> & faceArray);
+        void buildVertexMap(const HalfEdge::Mesh * originalMesh, const Array<uint> & unchartedMaterialArray);
+
+        bool closeHoles();
+
+        bool isDisk() const { return m_isDisk; }
+        bool isVertexMapped() const { return m_isVertexMapped; }
+
+        uint vertexCount() const { return m_chartMesh->vertexCount(); }
+        uint colocalVertexCount() const { return m_unifiedMesh->vertexCount(); }
+
+        uint faceCount() const { return m_faceArray.count(); }
+        uint faceAt(uint i) const { return m_faceArray[i]; }
+
+        const HalfEdge::Mesh * chartMesh() const { return m_chartMesh.ptr(); }
+        HalfEdge::Mesh * chartMesh() { return m_chartMesh.ptr(); }
+        const HalfEdge::Mesh * unifiedMesh() const { return m_unifiedMesh.ptr(); }
+        HalfEdge::Mesh * unifiedMesh() { return m_unifiedMesh.ptr(); }
+
+        //uint vertexIndex(uint i) const { return m_vertexIndexArray[i]; }
+
+        uint mapChartVertexToOriginalVertex(uint i) const { return m_chartToOriginalMap[i]; }
+        uint mapChartVertexToUnifiedVertex(uint i) const { return m_chartToUnifiedMap[i]; }
+
+        const Array<uint> & faceArray() const { return m_faceArray; }
+
+        void transferParameterization();
+
+        float computeSurfaceArea() const;
+        float computeParametricArea() const;
+        Vector2 computeParametricBounds() const;
+
+
+        float scale = 1.0f;
+        uint vertexMapWidth;
+        uint vertexMapHeight;
+
+    private:
+
+        bool closeLoop(uint start, const Array<HalfEdge::Edge *> & loop);
+
+        // Chart mesh.
+        AutoPtr<HalfEdge::Mesh> m_chartMesh;
+        AutoPtr<HalfEdge::Mesh> m_unifiedMesh;
+
+        bool m_isDisk;
+        bool m_isVertexMapped;
+
+        // List of faces of the original mesh that belong to this chart.
+        Array<uint> m_faceArray;
+
+        // Map vertices of the chart mesh to vertices of the original mesh.
+        Array<uint> m_chartToOriginalMap;
+
+        Array<uint> m_chartToUnifiedMap;
+    };
+
+} // nv namespace
+
+#endif // NV_MESH_ATLAS_H
diff --git a/thirdparty/thekla_atlas/nvmesh/param/AtlasBuilder.cpp b/thirdparty/thekla_atlas/nvmesh/param/AtlasBuilder.cpp
new file mode 100644
index 0000000000..bd2140c2f3
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/AtlasBuilder.cpp
@@ -0,0 +1,1320 @@
+// This code is in the public domain -- castano@gmail.com
+
+#include "nvmesh.h" // pch
+
+#include "AtlasBuilder.h"
+#include "Util.h"
+
+#include "nvmesh/halfedge/Mesh.h"
+#include "nvmesh/halfedge/Face.h"
+#include "nvmesh/halfedge/Vertex.h"
+
+#include "nvmath/Matrix.inl"
+#include "nvmath/Vector.inl"
+
+//#include "nvcore/IntroSort.h"
+#include "nvcore/Array.inl"
+
+#include <algorithm> // std::sort
+
+#include <float.h> // FLT_MAX
+#include <limits.h> // UINT_MAX
+
+using namespace nv;
+
+namespace
+{
+
+    // Dummy implementation of a priority queue using sort at insertion.
+    // - Insertion is o(n)
+    // - Smallest element goes at the end, so that popping it is o(1).
+    // - Resorting is n*log(n)
+    // @@ Number of elements in the queue is usually small, and we'd have to rebalance often. I'm not sure it's worth implementing a heap.
+    // @@ Searcing at removal would remove the need for sorting when priorities change.
+    struct PriorityQueue
+    {
+        PriorityQueue(uint size = UINT_MAX) : maxSize(size) {}
+
+        void push(float priority, uint face) {
+            uint i = 0;
+            const uint count = pairs.count();
+            for (; i < count; i++) {
+                if (pairs[i].priority > priority) break;
+            }
+
+            Pair p = { priority, face };
+            pairs.insertAt(i, p);
+
+            if (pairs.count() > maxSize) {
+                pairs.removeAt(0);
+            }
+        }
+
+        // push face out of order, to be sorted later.
+        void push(uint face) {
+            Pair p = { 0.0f, face };
+            pairs.append(p);
+        }
+
+        uint pop() {
+            uint f = pairs.back().face;
+            pairs.pop_back();
+            return f;
+        }
+
+        void sort() {
+            //nv::sort(pairs); // @@ My intro sort appears to be much slower than it should!
+            std::sort(pairs.buffer(), pairs.buffer() + pairs.count());
+        }
+
+        void clear() {
+            pairs.clear();
+        }
+
+        uint count() const { return pairs.count(); }
+
+        float firstPriority() const { return pairs.back().priority; }
+
+
+        const uint maxSize;
+        
+        struct Pair {
+            bool operator <(const Pair & p) const { return priority > p.priority; } // !! Sort in inverse priority order!
+            float priority;
+            uint face;
+        };
+        
+
+        Array<Pair> pairs;
+    };
+
+    static bool isNormalSeam(const HalfEdge::Edge * edge) {
+        return (edge->vertex->nor != edge->pair->next->vertex->nor || edge->next->vertex->nor != edge->pair->vertex->nor);
+    }
+
+    static bool isTextureSeam(const HalfEdge::Edge * edge) {
+        return (edge->vertex->tex != edge->pair->next->vertex->tex || edge->next->vertex->tex != edge->pair->vertex->tex);
+    }
+
+} // namespace
+
+
+struct nv::ChartBuildData
+{
+    ChartBuildData(int id) : id(id) {
+        planeNormal = Vector3(0);
+        centroid = Vector3(0);
+        coneAxis = Vector3(0);
+        coneAngle = 0;
+        area = 0;
+        boundaryLength = 0;
+        normalSum = Vector3(0);
+        centroidSum = Vector3(0);
+    }
+
+    int id;
+
+    // Proxy info:
+    Vector3 planeNormal;
+    Vector3 centroid;
+    Vector3 coneAxis;
+    float coneAngle;
+    
+    float area;
+    float boundaryLength;
+    Vector3 normalSum;
+    Vector3 centroidSum;
+    
+    Array<uint> seeds;  // @@ These could be a pointers to the HalfEdge faces directly.
+	Array<uint> faces;
+    PriorityQueue candidates;
+};
+
+
+
+AtlasBuilder::AtlasBuilder(const HalfEdge::Mesh * m) : mesh(m), facesLeft(m->faceCount())
+{
+    const uint faceCount = m->faceCount();
+    faceChartArray.resize(faceCount, -1);
+    faceCandidateArray.resize(faceCount, -1);
+
+    // @@ Floyd for the whole mesh is too slow. We could compute floyd progressively per patch as the patch grows. We need a better solution to compute most central faces.
+    //computeShortestPaths();
+
+    // Precompute edge lengths and face areas.
+    uint edgeCount = m->edgeCount();
+    edgeLengths.resize(edgeCount);
+
+    for (uint i = 0; i < edgeCount; i++) {
+        uint id = m->edgeAt(i)->id;
+        nvDebugCheck(id / 2 == i);
+
+        edgeLengths[i] = m->edgeAt(i)->length();
+    }
+
+    faceAreas.resize(faceCount);
+    for (uint i = 0; i < faceCount; i++) {
+        faceAreas[i] = m->faceAt(i)->area();
+    }
+}
+
+AtlasBuilder::~AtlasBuilder()
+{
+    const uint chartCount = chartArray.count();
+    for (uint i = 0; i < chartCount; i++)
+    {
+        delete chartArray[i];
+    }
+}
+
+
+void AtlasBuilder::markUnchartedFaces(const Array<uint> & unchartedFaces)
+{
+    const uint unchartedFaceCount = unchartedFaces.count();
+    for (uint i = 0; i < unchartedFaceCount; i++){ 
+        uint f = unchartedFaces[i];
+        faceChartArray[f] = -2;
+        //faceCandidateArray[f] = -2; // @@ ?
+
+        removeCandidate(f);
+    }
+
+    nvDebugCheck(facesLeft >= unchartedFaceCount);
+    facesLeft -= unchartedFaceCount;
+}
+
+
+void AtlasBuilder::computeShortestPaths()
+{
+    const uint faceCount = mesh->faceCount();
+    shortestPaths.resize(faceCount*faceCount, FLT_MAX);
+
+    // Fill edges:
+    for (uint i = 0; i < faceCount; i++)
+    {
+        shortestPaths[i*faceCount + i] = 0.0f;
+
+        const HalfEdge::Face * face_i = mesh->faceAt(i);
+        Vector3 centroid_i = face_i->centroid();
+
+        for (HalfEdge::Face::ConstEdgeIterator it(face_i->edges()); !it.isDone(); it.advance())
+        {
+            const HalfEdge::Edge * edge = it.current();
+
+            if (!edge->isBoundary())
+            {
+                const HalfEdge::Face * face_j = edge->pair->face;
+
+                uint j = face_j->id;
+                Vector3 centroid_j = face_j->centroid();
+
+                shortestPaths[i*faceCount + j] = shortestPaths[j*faceCount + i] = length(centroid_i - centroid_j);
+            }
+        }
+    }
+
+    // Use Floyd-Warshall algorithm to compute all paths:
+    for (uint k = 0; k < faceCount; k++)
+    {
+        for (uint i = 0; i < faceCount; i++)
+        {
+            for (uint j = 0; j < faceCount; j++)
+            {
+                shortestPaths[i*faceCount + j] = min(shortestPaths[i*faceCount + j], shortestPaths[i*faceCount + k]+shortestPaths[k*faceCount + j]);
+            }
+        }
+    }
+}
+
+
+void AtlasBuilder::placeSeeds(float threshold, uint maxSeedCount)
+{
+    // Instead of using a predefiened number of seeds:
+    // - Add seeds one by one, growing chart until a certain treshold.
+    // - Undo charts and restart growing process.
+
+    // @@ How can we give preference to faces far from sharp features as in the LSCM paper?
+    //   - those points can be found using a simple flood filling algorithm.
+    //   - how do we weight the probabilities?
+
+    for (uint i = 0; i < maxSeedCount; i++)
+    {
+        if (facesLeft == 0) {
+            // No faces left, stop creating seeds.
+            break;
+        }
+
+        createRandomChart(threshold);
+    }
+}
+
+
+void AtlasBuilder::createRandomChart(float threshold)
+{
+    ChartBuildData * chart = new ChartBuildData(chartArray.count());
+    chartArray.append(chart);
+
+    // Pick random face that is not used by any chart yet.
+    uint randomFaceIdx = rand.getRange(facesLeft - 1);
+    uint i = 0;
+    for (uint f = 0; f != randomFaceIdx; f++, i++)
+    {
+        while (faceChartArray[i] != -1) i++;
+    }
+    while (faceChartArray[i] != -1) i++;
+
+    chart->seeds.append(i);
+
+    addFaceToChart(chart, i, true);
+
+    // Grow the chart as much as possible within the given threshold.
+    growChart(chart, threshold * 0.5f, facesLeft);
+    //growCharts(threshold - threshold * 0.75f / chartCount(), facesLeft);
+}
+
+void AtlasBuilder::addFaceToChart(ChartBuildData * chart, uint f, bool recomputeProxy)
+{
+    // Add face to chart.
+    chart->faces.append(f);
+
+    nvDebugCheck(faceChartArray[f] == -1);
+    faceChartArray[f] = chart->id;
+
+    facesLeft--;
+
+    // Update area and boundary length.
+    chart->area = evaluateChartArea(chart, f);
+    chart->boundaryLength = evaluateBoundaryLength(chart, f);
+    chart->normalSum = evaluateChartNormalSum(chart, f);
+    chart->centroidSum = evaluateChartCentroidSum(chart, f);
+
+    if (recomputeProxy) {
+        // Update proxy and candidate's priorities.
+        updateProxy(chart);
+    }
+
+    // Update candidates.
+    removeCandidate(f);
+    updateCandidates(chart, f);
+    updatePriorities(chart);
+}
+
+// @@ Get N best candidates in one pass.
+const AtlasBuilder::Candidate & AtlasBuilder::getBestCandidate() const
+{
+    uint best = 0;
+    float bestCandidateMetric = FLT_MAX;
+
+    const uint candidateCount = candidateArray.count();
+    nvCheck(candidateCount > 0);
+
+    for (uint i = 0; i < candidateCount; i++)
+    {
+        const Candidate & candidate = candidateArray[i];
+    
+        if (candidate.metric < bestCandidateMetric) {
+            bestCandidateMetric = candidate.metric;
+            best = i;
+        }
+    }
+
+    return candidateArray[best];
+}
+
+
+// Returns true if any of the charts can grow more.
+bool AtlasBuilder::growCharts(float threshold, uint faceCount)
+{
+#if 1 // Using one global list.
+
+    faceCount = min(faceCount, facesLeft);
+
+    for (uint i = 0; i < faceCount; i++)
+    {
+        const Candidate & candidate = getBestCandidate();
+        
+        if (candidate.metric > threshold) {
+            return false; // Can't grow more.
+        }
+
+        addFaceToChart(candidate.chart, candidate.face);
+    }
+
+    return facesLeft != 0; // Can continue growing.
+
+#else // Using one list per chart.
+    bool canGrowMore = false;
+
+    const uint chartCount = chartArray.count();
+    for (uint i = 0; i < chartCount; i++)
+    {
+        if (growChart(chartArray[i], threshold, faceCount))
+        {
+            canGrowMore = true;
+        }
+    }
+
+    return canGrowMore;
+#endif
+}
+
+bool AtlasBuilder::growChart(ChartBuildData * chart, float threshold, uint faceCount)
+{
+    // Try to add faceCount faces within threshold to chart.
+    for (uint i = 0; i < faceCount; )
+    {
+        if (chart->candidates.count() == 0 || chart->candidates.firstPriority() > threshold)
+        {
+            return false;
+        }
+
+        uint f = chart->candidates.pop();
+        if (faceChartArray[f] == -1)
+        {
+            addFaceToChart(chart, f);
+            i++;
+        }
+    }
+
+    if (chart->candidates.count() == 0 || chart->candidates.firstPriority() > threshold)
+    {
+        return false;
+    }
+
+    return true;
+}
+
+
+void AtlasBuilder::resetCharts()
+{
+    const uint faceCount = mesh->faceCount();
+    for (uint i = 0; i < faceCount; i++)
+    {
+        faceChartArray[i] = -1;
+        faceCandidateArray[i] = -1;
+    }
+
+    facesLeft = faceCount;
+
+    candidateArray.clear();
+
+    const uint chartCount = chartArray.count();
+    for (uint i = 0; i < chartCount; i++)
+    {
+        ChartBuildData * chart = chartArray[i];
+
+        const uint seed = chart->seeds.back();
+
+        chart->area = 0.0f;
+        chart->boundaryLength = 0.0f;
+        chart->normalSum = Vector3(0);
+        chart->centroidSum = Vector3(0);
+
+        chart->faces.clear();
+        chart->candidates.clear();
+
+        addFaceToChart(chart, seed);
+    }
+}
+
+
+void AtlasBuilder::updateCandidates(ChartBuildData * chart, uint f)
+{
+    const HalfEdge::Face * face = mesh->faceAt(f);
+
+    // Traverse neighboring faces, add the ones that do not belong to any chart yet.
+    for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+    {
+        const HalfEdge::Edge * edge = it.current()->pair;
+
+        if (!edge->isBoundary())
+        {
+            uint f = edge->face->id;
+
+            if (faceChartArray[f] == -1)
+            {
+                chart->candidates.push(f);
+            }
+        }
+    }
+}
+
+
+void AtlasBuilder::updateProxies()
+{
+    const uint chartCount = chartArray.count();
+    for (uint i = 0; i < chartCount; i++)
+    {
+        updateProxy(chartArray[i]);
+    }
+}
+
+
+namespace {
+
+    float absoluteSum(Vector4::Arg v)
+    {
+        return fabs(v.x) + fabs(v.y) + fabs(v.z) + fabs(v.w);
+    }
+
+    //#pragma message(NV_FILE_LINE "FIXME: Using the c=cos(teta) substitution, the equation system becomes linear and we can avoid the newton solver.")
+
+    struct ConeFitting
+    {
+        ConeFitting(const HalfEdge::Mesh * m, float g, float tf, float tx) : mesh(m), gamma(g), tolf(tf), tolx(tx), F(0), D(0), H(0) {
+        }
+
+        void addTerm(Vector3 N, float A)
+        {
+            const float c = cosf(X.w);
+            const float s = sinf(X.w);
+            const float tmp = dot(X.xyz(), N) - c;
+
+            F += tmp * tmp;
+
+            D.x += 2 * X.x * tmp;
+            D.y += 2 * X.y * tmp;
+            D.z += 2 * X.z * tmp;
+            D.w += 2 * s * tmp;
+
+            H(0,0) = 2 * X.x * N.x + 2 * tmp;
+            H(0,1) = 2 * X.x * N.y;
+            H(0,2) = 2 * X.x * N.z;
+            H(0,3) = 2 * X.x * s;
+
+            H(1,0) = 2 * X.y * N.x;
+            H(1,1) = 2 * X.y * N.y + 2 * tmp;
+            H(1,2) = 2 * X.y * N.z;
+            H(1,3) = 2 * X.y * s;
+
+            H(2,0) = 2 * X.z * N.x;
+            H(2,1) = 2 * X.z * N.y;
+            H(2,2) = 2 * X.z * N.z + 2 * tmp;
+            H(2,3) = 2 * X.z * s;
+
+            H(3,0) = 2 * s * N.x;
+            H(3,1) = 2 * s * N.y;
+            H(3,2) = 2 * s * N.z;
+            H(3,3) = 2 * s * s + 2 * c * tmp;
+        }
+
+        Vector4 solve(ChartBuildData * chart, Vector4 start)
+        {
+            const uint faceCount = chart->faces.count();
+
+            X = start;
+            
+            Vector4 dX;
+
+            do {
+                for (uint i = 0; i < faceCount; i++)
+                {
+                    const HalfEdge::Face * face = mesh->faceAt(chart->faces[i]);
+
+                    addTerm(face->normal(), face->area());
+                }
+
+                Vector4 dX;
+                //solveKramer(H, D, &dX);
+                solveLU(H, D, &dX);
+
+                // @@ Do a full newton step and reduce by half if F doesn't decrease.
+                X -= gamma * dX;
+
+                // Constrain normal to be normalized.
+                X = Vector4(normalize(X.xyz()), X.w);
+                
+            } while(absoluteSum(D) > tolf || absoluteSum(dX) > tolx);
+
+            return X;
+        }
+
+        HalfEdge::Mesh const * const mesh;
+        const float gamma;
+        const float tolf;
+        const float tolx;
+
+        Vector4 X;
+
+        float F;
+        Vector4 D;
+        Matrix H;
+    };
+
+    // Unnormalized face normal assuming it's a triangle.
+    static Vector3 triangleNormal(const HalfEdge::Face * face)
+    {
+        Vector3 p0 = face->edge->vertex->pos;
+        Vector3 p1 = face->edge->next->vertex->pos;
+        Vector3 p2 = face->edge->next->next->vertex->pos;
+
+        Vector3 e0 = p2 - p0;
+        Vector3 e1 = p1 - p0;
+
+        return normalizeSafe(cross(e0, e1), Vector3(0), 0.0f);
+    }
+
+    static Vector3 triangleNormalAreaScaled(const HalfEdge::Face * face)
+    {
+        Vector3 p0 = face->edge->vertex->pos;
+        Vector3 p1 = face->edge->next->vertex->pos;
+        Vector3 p2 = face->edge->next->next->vertex->pos;
+
+        Vector3 e0 = p2 - p0;
+        Vector3 e1 = p1 - p0;
+
+        return cross(e0, e1);
+    }
+
+    // Average of the edge midpoints weighted by the edge length.
+    // I want a point inside the triangle, but closer to the cirumcenter.
+    static Vector3 triangleCenter(const HalfEdge::Face * face)
+    {
+        Vector3 p0 = face->edge->vertex->pos;
+        Vector3 p1 = face->edge->next->vertex->pos;
+        Vector3 p2 = face->edge->next->next->vertex->pos;
+
+        float l0 = length(p1 - p0);
+        float l1 = length(p2 - p1);
+        float l2 = length(p0 - p2);
+
+        Vector3 m0 = (p0 + p1) * l0 / (l0 + l1 + l2);
+        Vector3 m1 = (p1 + p2) * l1 / (l0 + l1 + l2);
+        Vector3 m2 = (p2 + p0) * l2 / (l0 + l1 + l2);
+
+        return m0 + m1 + m2;
+    }
+
+} // namespace
+
+void AtlasBuilder::updateProxy(ChartBuildData * chart)
+{
+    //#pragma message(NV_FILE_LINE "TODO: Use best fit plane instead of average normal.")
+
+    chart->planeNormal = normalizeSafe(chart->normalSum, Vector3(0), 0.0f);
+    chart->centroid = chart->centroidSum / float(chart->faces.count());
+
+    //#pragma message(NV_FILE_LINE "TODO: Experiment with conic fitting.")
+
+    // F = (Nc*Nt - cos Oc)^2 = (x*Nt_x + y*Nt_y + z*Nt_z - cos w)^2
+    // dF/dx = 2 * x * (x*Nt_x + y*Nt_y + z*Nt_z - cos w)
+    // dF/dy = 2 * y * (x*Nt_x + y*Nt_y + z*Nt_z - cos w)
+    // dF/dz = 2 * z * (x*Nt_x + y*Nt_y + z*Nt_z - cos w)
+    // dF/dw = 2 * sin w * (x*Nt_x + y*Nt_y + z*Nt_z - cos w)
+
+    // JacobianMatrix({
+    // 2 * x * (x*Nt_x + y*Nt_y + z*Nt_z - Cos(w)),
+    // 2 * y * (x*Nt_x + y*Nt_y + z*Nt_z - Cos(w)),
+    // 2 * z * (x*Nt_x + y*Nt_y + z*Nt_z - Cos(w)),
+    // 2 * Sin(w) * (x*Nt_x + y*Nt_y + z*Nt_z - Cos(w))}, {x,y,z,w})
+
+    // H[0,0] = 2 * x * Nt_x + 2 * (x*Nt_x + y*Nt_y + z*Nt_z - cos(w));
+    // H[0,1] = 2 * x * Nt_y;
+    // H[0,2] = 2 * x * Nt_z;
+    // H[0,3] = 2 * x * sin(w);
+
+    // H[1,0] = 2 * y * Nt_x;
+    // H[1,1] = 2 * y * Nt_y + 2 * (x*Nt_x + y*Nt_y + z*Nt_z - cos(w));
+    // H[1,2] = 2 * y * Nt_z;
+    // H[1,3] = 2 * y * sin(w);
+
+    // H[2,0] = 2 * z * Nt_x;
+    // H[2,1] = 2 * z * Nt_y;
+    // H[2,2] = 2 * z * Nt_z + 2 * (x*Nt_x + y*Nt_y + z*Nt_z - cos(w));
+    // H[2,3] = 2 * z * sin(w);
+
+    // H[3,0] = 2 * sin(w) * Nt_x;
+    // H[3,1] = 2 * sin(w) * Nt_y;
+    // H[3,2] = 2 * sin(w) * Nt_z;
+    // H[3,3] = 2 * sin(w) * sin(w) + 2 * cos(w) * (x*Nt_x + y*Nt_y + z*Nt_z - cos(w));
+
+    // @@ Cone fitting might be quite slow.
+
+    /*ConeFitting coneFitting(mesh, 0.1f, 0.001f, 0.001f);
+
+    Vector4 start = Vector4(chart->coneAxis, chart->coneAngle);
+    Vector4 solution = coneFitting.solve(chart, start);
+
+    chart->coneAxis = solution.xyz();
+    chart->coneAngle = solution.w;*/
+}
+
+
+
+bool AtlasBuilder::relocateSeeds()
+{
+    bool anySeedChanged = false;
+
+    const uint chartCount = chartArray.count();
+    for (uint i = 0; i < chartCount; i++)
+    {
+        if (relocateSeed(chartArray[i]))
+        {
+            anySeedChanged = true;
+        }
+    }
+
+    return anySeedChanged;
+}
+
+
+bool AtlasBuilder::relocateSeed(ChartBuildData * chart)
+{
+    Vector3 centroid = computeChartCentroid(chart);
+
+    const uint N = 10;  // @@ Hardcoded to 10?
+    PriorityQueue bestTriangles(N); 
+
+    // Find the first N triangles that fit the proxy best.
+    const uint faceCount = chart->faces.count();
+    for (uint i = 0; i < faceCount; i++)
+    {
+        float priority = evaluateProxyFitMetric(chart, chart->faces[i]);
+        bestTriangles.push(priority, chart->faces[i]);
+    }
+
+    // Of those, choose the most central triangle.
+    uint mostCentral;
+    float maxDistance = -1;
+
+    const uint bestCount = bestTriangles.count();
+    for (uint i = 0; i < bestCount; i++)
+    {
+        const HalfEdge::Face * face = mesh->faceAt(bestTriangles.pairs[i].face);
+        Vector3 faceCentroid = triangleCenter(face);
+
+        float distance = length(centroid - faceCentroid);
+
+        /*#pragma message(NV_FILE_LINE "TODO: Implement evaluateDistanceToBoundary.")
+        float distance = evaluateDistanceToBoundary(chart, bestTriangles.pairs[i].face);*/
+        
+        if (distance > maxDistance)
+        {
+            maxDistance = distance;
+            mostCentral = bestTriangles.pairs[i].face;
+        }
+    }
+    nvDebugCheck(maxDistance >= 0);
+
+    // In order to prevent k-means cyles we record all the previously chosen seeds.
+    uint index;
+    if (chart->seeds.find(mostCentral, &index))
+    {
+        // Move new seed to the end of the seed array.
+        uint last = chart->seeds.count() - 1;
+        swap(chart->seeds[index], chart->seeds[last]);
+        return false;
+    }
+    else
+    {
+        // Append new seed.
+        chart->seeds.append(mostCentral);
+        return true;
+    }
+}
+
+void AtlasBuilder::removeCandidate(uint f)
+{
+    int c = faceCandidateArray[f];
+    if (c != -1) {
+        faceCandidateArray[f] = -1;
+
+        if (c == candidateArray.count() - 1) {
+            candidateArray.popBack();
+        }
+        else {
+            candidateArray.replaceWithLast(c);
+            faceCandidateArray[candidateArray[c].face] = c;
+        }
+    }
+}
+
+void AtlasBuilder::updateCandidate(ChartBuildData * chart, uint f, float metric)
+{
+    if (faceCandidateArray[f] == -1) {
+        const uint index = candidateArray.count();
+        faceCandidateArray[f] = index;
+        candidateArray.resize(index + 1);
+        candidateArray[index].face = f;
+        candidateArray[index].chart = chart;
+        candidateArray[index].metric = metric;
+    }
+    else {
+        int c = faceCandidateArray[f];
+        nvDebugCheck(c != -1);
+
+        Candidate & candidate = candidateArray[c];
+        nvDebugCheck(candidate.face == f);
+
+        if (metric < candidate.metric || chart == candidate.chart) {
+            candidate.metric = metric;
+            candidate.chart = chart;
+        }
+    }
+
+}
+
+
+void AtlasBuilder::updatePriorities(ChartBuildData * chart)
+{
+    // Re-evaluate candidate priorities.
+    uint candidateCount = chart->candidates.count();
+    for (uint i = 0; i < candidateCount; i++)
+    {
+        chart->candidates.pairs[i].priority = evaluatePriority(chart, chart->candidates.pairs[i].face);
+
+        if (faceChartArray[chart->candidates.pairs[i].face] == -1)
+        {
+            updateCandidate(chart, chart->candidates.pairs[i].face, chart->candidates.pairs[i].priority);
+        }
+    }
+
+    // Sort candidates.
+    chart->candidates.sort();
+}
+
+
+// Evaluate combined metric.
+float AtlasBuilder::evaluatePriority(ChartBuildData * chart, uint face)
+{
+    // Estimate boundary length and area:
+    float newBoundaryLength = evaluateBoundaryLength(chart, face);
+    float newChartArea = evaluateChartArea(chart, face);
+
+    float F = evaluateProxyFitMetric(chart, face);
+    float C = evaluateRoundnessMetric(chart, face, newBoundaryLength, newChartArea);
+    float P = evaluateStraightnessMetric(chart, face);
+
+    // Penalize faces that cross seams, reward faces that close seams or reach boundaries.
+    float N = evaluateNormalSeamMetric(chart, face);
+    float T = evaluateTextureSeamMetric(chart, face);
+
+    //float R = evaluateCompletenessMetric(chart, face);
+
+    //float D = evaluateDihedralAngleMetric(chart, face);
+    // @@ Add a metric based on local dihedral angle.
+
+    // @@ Tweaking the normal and texture seam metrics.
+    // - Cause more impedance. Never cross 90 degree edges.
+    // - 
+
+    float cost = float(
+        settings.proxyFitMetricWeight * F + 
+        settings.roundnessMetricWeight * C + 
+        settings.straightnessMetricWeight * P +
+        settings.normalSeamMetricWeight * N +
+        settings.textureSeamMetricWeight * T);
+
+    /*cost = settings.proxyFitMetricWeight * powf(F, settings.proxyFitMetricExponent);
+    cost = max(cost, settings.roundnessMetricWeight * powf(C, settings.roundnessMetricExponent));
+    cost = max(cost, settings.straightnessMetricWeight * pow(P, settings.straightnessMetricExponent));
+    cost = max(cost, settings.normalSeamMetricWeight * N);
+    cost = max(cost, settings.textureSeamMetricWeight * T);*/
+
+    // Enforce limits strictly:
+    if (newChartArea > settings.maxChartArea) cost = FLT_MAX;
+    if (newBoundaryLength > settings.maxBoundaryLength) cost = FLT_MAX;
+
+    // Make sure normal seams are fully respected:
+    if (settings.normalSeamMetricWeight >= 1000 && N != 0) cost = FLT_MAX;
+
+    nvCheck(isFinite(cost));
+    return cost;
+}
+
+
+// Returns a value in [0-1].
+float AtlasBuilder::evaluateProxyFitMetric(ChartBuildData * chart, uint f)
+{
+    const HalfEdge::Face * face = mesh->faceAt(f);
+    Vector3 faceNormal = triangleNormal(face);
+    //return square(dot(chart->coneAxis, faceNormal) - cosf(chart->coneAngle));
+
+    // Use plane fitting metric for now:
+    //return square(1 - dot(faceNormal, chart->planeNormal)); // @@ normal deviations should be weighted by face area
+    return 1 - dot(faceNormal, chart->planeNormal); // @@ normal deviations should be weighted by face area
+
+    // Find distance to chart.
+    /*Vector3 faceCentroid = face->centroid();
+
+    float dist = 0;
+    int count = 0;
+
+    for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+    {
+        const HalfEdge::Edge * edge = it.current();
+
+        if (!edge->isBoundary()) {
+            const HalfEdge::Face * neighborFace = edge->pair()->face();
+            if (faceChartArray[neighborFace->id()] == chart->id) {
+                dist += length(neighborFace->centroid() - faceCentroid);
+                count++;
+            }
+        }
+    }
+
+    dist /= (count * count);
+
+    return (1 - dot(faceNormal, chart->planeNormal)) * dist;*/
+
+    //return (1 - dot(faceNormal, chart->planeNormal));
+}
+
+float AtlasBuilder::evaluateDistanceToBoundary(ChartBuildData * chart, uint face)
+{
+//#pragma message(NV_FILE_LINE "TODO: Evaluate distance to boundary metric.")
+
+    // @@ This is needed for the seed relocation code.
+    // @@ This could provide a better roundness metric.
+    
+    return 0.0f;
+}
+
+float AtlasBuilder::evaluateDistanceToSeed(ChartBuildData * chart, uint f)
+{
+    //const uint seed = chart->seeds.back();
+    //const uint faceCount = mesh->faceCount();
+    //return shortestPaths[seed * faceCount + f];
+
+    const HalfEdge::Face * seed = mesh->faceAt(chart->seeds.back());
+    const HalfEdge::Face * face = mesh->faceAt(f);
+    return length(triangleCenter(seed) - triangleCenter(face));
+}
+
+
+float AtlasBuilder::evaluateRoundnessMetric(ChartBuildData * chart, uint face, float newBoundaryLength, float newChartArea)
+{
+    // @@ D-charts use distance to seed.
+    // C(c,t) = pi * D(S_c,t)^2 / A_c
+    //return PI * square(evaluateDistanceToSeed(chart, face)) / chart->area;
+    //return PI * square(evaluateDistanceToSeed(chart, face)) / chart->area;
+    //return 2 * PI * evaluateDistanceToSeed(chart, face) / chart->boundaryLength;
+
+    // Garland's Hierarchical Face Clustering paper uses ratio between boundary and area, which is easier to compute and might work as well:
+    // roundness = D^2/4*pi*A -> circle = 1, non circle greater than 1
+
+    //return square(newBoundaryLength) / (newChartArea * 4 * PI);
+    float roundness = square(chart->boundaryLength) / chart->area;
+    float newRoundness = square(newBoundaryLength) / newChartArea;
+    if (newRoundness > roundness) {
+        return square(newBoundaryLength) / (newChartArea * 4 * PI);
+    }
+    else {
+        // Offer no impedance to faces that improve roundness.
+        return 0;
+    }
+
+    //return square(newBoundaryLength) / (4 * PI * newChartArea);
+    //return clamp(1 - (4 * PI * newChartArea) / square(newBoundaryLength), 0.0f, 1.0f);
+
+    // Use the ratio between the new roundness vs. the previous roundness.
+    // - If we use the absolute metric, when the initial face is very long, then it's hard to make any progress.
+    //return (square(newBoundaryLength) * chart->area) / (square(chart->boundaryLength) * newChartArea);
+    //return (4 * PI * newChartArea) / square(newBoundaryLength) - (4 * PI * chart->area) / square(chart->boundaryLength);
+
+    //if (square(newBoundaryLength) * chart->area) / (square(chart->boundaryLength) * newChartArea);
+
+}
+
+float AtlasBuilder::evaluateStraightnessMetric(ChartBuildData * chart, uint f)
+{
+    float l_out = 0.0f;
+    float l_in = 0.0f;
+
+    const HalfEdge::Face * face = mesh->faceAt(f);
+    for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+    {
+        const HalfEdge::Edge * edge = it.current();
+
+        //float l = edge->length();
+        float l = edgeLengths[edge->id/2];
+
+        if (edge->isBoundary())
+        {
+            l_out += l;
+        }
+        else
+        {
+            uint neighborFaceId = edge->pair->face->id;
+            if (faceChartArray[neighborFaceId] != chart->id) {
+                l_out += l;
+            }
+            else {
+                l_in += l;
+            }
+        }
+    }
+    nvDebugCheck(l_in != 0.0f); // Candidate face must be adjacent to chart. @@ This is not true if the input mesh has zero-length edges.
+
+    //return l_out / l_in;
+    float ratio = (l_out - l_in) / (l_out + l_in);
+    //if (ratio < 0) ratio *= 10; // Encourage closing gaps.
+    return min(ratio, 0.0f); // Only use the straightness metric to close gaps.
+    //return ratio;
+}
+
+
+float AtlasBuilder::evaluateNormalSeamMetric(ChartBuildData * chart, uint f)
+{
+    float seamFactor = 0.0f;
+    float totalLength = 0.0f;
+    
+    const HalfEdge::Face * face = mesh->faceAt(f);
+    for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+    {
+        const HalfEdge::Edge * edge = it.current();
+
+        if (edge->isBoundary()) {
+            continue;
+        }
+
+        const uint neighborFaceId = edge->pair->face->id;
+        if (faceChartArray[neighborFaceId] != chart->id) {
+            continue;
+        }
+
+        //float l = edge->length();
+        float l = edgeLengths[edge->id/2];
+
+        totalLength += l;
+
+        if (!edge->isSeam()) {
+            continue;
+        }
+
+        // Make sure it's a normal seam.
+        if (isNormalSeam(edge))
+        {
+            float d0 = clamp(dot(edge->vertex->nor, edge->pair->next->vertex->nor), 0.0f, 1.0f);
+            float d1 = clamp(dot(edge->next->vertex->nor, edge->pair->vertex->nor), 0.0f, 1.0f);
+            //float a0 = clamp(acosf(d0) / (PI/2), 0.0f, 1.0f);
+            //float a1 = clamp(acosf(d1) / (PI/2), 0.0f, 1.0f);
+            //l *= (a0 + a1) * 0.5f;
+
+            l *= 1 - (d0 + d1) * 0.5f;
+
+            seamFactor += l;
+        }
+    }
+
+    if (seamFactor == 0) return 0.0f;
+    return seamFactor / totalLength;
+}
+
+
+float AtlasBuilder::evaluateTextureSeamMetric(ChartBuildData * chart, uint f)
+{
+    float seamLength = 0.0f;
+    //float newSeamLength = 0.0f;
+    //float oldSeamLength = 0.0f;
+    float totalLength = 0.0f;
+    
+    const HalfEdge::Face * face = mesh->faceAt(f);
+    for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+    {
+        const HalfEdge::Edge * edge = it.current();
+
+        /*float l = edge->length();
+        totalLength += l;
+
+        if (edge->isBoundary() || !edge->isSeam()) {
+            continue;
+        }
+
+        // Make sure it's a texture seam.
+        if (isTextureSeam(edge))
+        {
+            uint neighborFaceId = edge->pair()->face()->id();
+            if (faceChartArray[neighborFaceId] != chart->id) {
+                newSeamLength += l;
+            }
+            else {
+                oldSeamLength += l;
+            }
+        }*/
+
+        if (edge->isBoundary()) {
+            continue;
+        }
+
+        const uint neighborFaceId = edge->pair->face->id;
+        if (faceChartArray[neighborFaceId] != chart->id) {
+            continue;
+        }
+
+        //float l = edge->length();
+        float l = edgeLengths[edge->id/2];
+        totalLength += l;
+
+        if (!edge->isSeam()) {
+            continue;
+        }
+
+        // Make sure it's a texture seam.
+        if (isTextureSeam(edge))
+        {
+            seamLength += l;
+        }
+    }
+
+    if (seamLength == 0.0f) {
+        return 0.0f; // Avoid division by zero.
+    }
+    
+    return seamLength / totalLength;
+}
+
+
+float AtlasBuilder::evaluateSeamMetric(ChartBuildData * chart, uint f)
+{
+    float newSeamLength = 0.0f;
+    float oldSeamLength = 0.0f;
+    float totalLength = 0.0f;
+    
+    const HalfEdge::Face * face = mesh->faceAt(f);
+    for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+    {
+        const HalfEdge::Edge * edge = it.current();
+
+        //float l = edge->length();
+        float l = edgeLengths[edge->id/2];
+
+        if (edge->isBoundary())
+        {
+            newSeamLength += l;
+        }
+        else
+        {
+            if (edge->isSeam())
+            {
+                uint neighborFaceId = edge->pair->face->id;
+                if (faceChartArray[neighborFaceId] != chart->id) {
+                    newSeamLength += l;
+                }
+                else {
+                    oldSeamLength += l;
+                }
+            }
+        }
+
+        totalLength += l;
+    }
+
+    return (newSeamLength - oldSeamLength) / totalLength;
+}
+
+
+float AtlasBuilder::evaluateChartArea(ChartBuildData * chart, uint f)
+{
+    const HalfEdge::Face * face = mesh->faceAt(f);
+    //return chart->area + face->area();
+    return chart->area + faceAreas[face->id];
+}
+
+
+float AtlasBuilder::evaluateBoundaryLength(ChartBuildData * chart, uint f)
+{
+    float boundaryLength = chart->boundaryLength;
+
+    // Add new edges, subtract edges shared with the chart.
+    const HalfEdge::Face * face = mesh->faceAt(f);
+    for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+    {
+        const HalfEdge::Edge * edge = it.current();
+        //float edgeLength = edge->length();
+        float edgeLength = edgeLengths[edge->id/2];
+
+        if (edge->isBoundary())
+        {
+            boundaryLength += edgeLength;
+        }
+        else
+        {
+            uint neighborFaceId = edge->pair->face->id;
+            if (faceChartArray[neighborFaceId] != chart->id) {
+                boundaryLength += edgeLength;
+            }
+            else {
+                boundaryLength -= edgeLength;
+            }
+        }
+    }
+    //nvDebugCheck(boundaryLength >= 0);
+
+    return max(0.0f, boundaryLength);  // @@ Hack!
+}
+
+Vector3 AtlasBuilder::evaluateChartNormalSum(ChartBuildData * chart, uint f)
+{
+    const HalfEdge::Face * face = mesh->faceAt(f);
+    return chart->normalSum + triangleNormalAreaScaled(face);
+}
+
+Vector3 AtlasBuilder::evaluateChartCentroidSum(ChartBuildData * chart, uint f)
+{
+    const HalfEdge::Face * face = mesh->faceAt(f);
+    return chart->centroidSum + face->centroid();
+}
+
+
+Vector3 AtlasBuilder::computeChartCentroid(const ChartBuildData * chart)
+{
+    Vector3 centroid(0);
+
+    const uint faceCount = chart->faces.count();
+    for (uint i = 0; i < faceCount; i++)
+    {
+        const HalfEdge::Face * face = mesh->faceAt(chart->faces[i]);
+        centroid += triangleCenter(face);
+    }
+
+    return centroid / float(faceCount);
+}
+
+
+void AtlasBuilder::fillHoles(float threshold)
+{
+    while (facesLeft > 0)
+    {
+        createRandomChart(threshold);
+    }
+}
+
+
+void AtlasBuilder::mergeChart(ChartBuildData * owner, ChartBuildData * chart, float sharedBoundaryLength)
+{
+    const uint faceCount = chart->faces.count();
+    for (uint i = 0; i < faceCount; i++)
+    {
+        uint f = chart->faces[i];
+        
+        nvDebugCheck(faceChartArray[f] == chart->id);
+        faceChartArray[f] = owner->id;
+
+        owner->faces.append(f);
+    }
+
+    // Update adjacencies?
+
+    owner->area += chart->area;
+    owner->boundaryLength += chart->boundaryLength - sharedBoundaryLength;
+
+    owner->normalSum += chart->normalSum;
+    owner->centroidSum += chart->centroidSum;
+
+    updateProxy(owner);
+}
+
+void AtlasBuilder::mergeCharts()
+{
+    Array<float> sharedBoundaryLengths;
+
+    const uint chartCount = chartArray.count();
+    for (int c = chartCount-1; c >= 0; c--)
+    {
+        sharedBoundaryLengths.clear();
+        sharedBoundaryLengths.resize(chartCount, 0.0f);
+
+        ChartBuildData * chart = chartArray[c];
+
+        float externalBoundary = 0.0f;
+
+        const uint faceCount = chart->faces.count();
+        for (uint i = 0; i < faceCount; i++)
+        {
+            uint f = chart->faces[i];
+            const HalfEdge::Face * face = mesh->faceAt(f);
+
+            for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+            {
+                const HalfEdge::Edge * edge = it.current();
+
+                //float l = edge->length();
+                float l = edgeLengths[edge->id/2];
+
+                if (edge->isBoundary()) {
+                    externalBoundary += l;
+                }
+                else {
+                    uint neighborFace = edge->pair->face->id;
+                    uint neighborChart = faceChartArray[neighborFace];
+
+                    if (neighborChart != c) {
+                        if ((edge->isSeam() && (isNormalSeam(edge) || isTextureSeam(edge))) || neighborChart == -2) {
+                            externalBoundary += l;
+                        }
+                        else {
+                            sharedBoundaryLengths[neighborChart] += l;
+                        }
+                    }
+                }
+            }
+        }
+
+        for (int cc = chartCount-1; cc >= 0; cc--)
+        {
+            if (cc == c) 
+                continue;
+
+            ChartBuildData * chart2 = chartArray[cc];
+            if (chart2 == NULL) 
+                continue;
+
+            if (sharedBoundaryLengths[cc] > 0.8 * max(0.0f, chart->boundaryLength - externalBoundary)) {
+
+                // Try to avoid degenerate configurations.
+                if (chart2->boundaryLength > sharedBoundaryLengths[cc])
+                {
+                    if (dot(chart2->planeNormal, chart->planeNormal) > -0.25) {
+                        mergeChart(chart2, chart, sharedBoundaryLengths[cc]);
+                        delete chart;
+                        chartArray[c] = NULL;
+                        break;
+                    }
+                }
+            }
+
+            if (sharedBoundaryLengths[cc] > 0.20 * max(0.0f, chart->boundaryLength - externalBoundary)) {
+
+                // Compare proxies.
+                if (dot(chart2->planeNormal, chart->planeNormal) > 0) {
+                    mergeChart(chart2, chart, sharedBoundaryLengths[cc]);
+                    delete chart;
+                    chartArray[c] = NULL;
+                    break;
+                }
+            }
+        }
+    }
+
+    // Remove deleted charts.
+    for (int c = 0; c < I32(chartArray.count()); /*do not increment if removed*/)
+    {
+        if (chartArray[c] == NULL) {
+            chartArray.removeAt(c);
+
+            // Update faceChartArray.
+            const uint faceCount = faceChartArray.count();
+            for (uint i = 0; i < faceCount; i++) {
+                nvDebugCheck (faceChartArray[i] != -1);
+                nvDebugCheck (faceChartArray[i] != c);
+                nvDebugCheck (faceChartArray[i] <= I32(chartArray.count()));
+
+                if (faceChartArray[i] > c) {
+                    faceChartArray[i]--;
+                }
+            }
+        }
+        else {
+            chartArray[c]->id = c;
+            c++;
+        }
+    }
+}
+
+
+
+const Array<uint> & AtlasBuilder::chartFaces(uint i) const
+{
+    return chartArray[i]->faces;
+}
diff --git a/thirdparty/thekla_atlas/nvmesh/param/AtlasBuilder.h b/thirdparty/thekla_atlas/nvmesh/param/AtlasBuilder.h
new file mode 100644
index 0000000000..f25c724f7e
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/AtlasBuilder.h
@@ -0,0 +1,111 @@
+// This code is in the public domain -- castano@gmail.com
+
+#pragma once
+#ifndef NV_MESH_ATLASBUILDER_H
+#define NV_MESH_ATLASBUILDER_H
+
+#include "Atlas.h"
+
+#include "nvmath/Vector.h"
+#include "nvmath/Random.h"
+#include "nvmesh/nvmesh.h"
+
+#include "nvcore/Array.h"
+#include "nvcore/BitArray.h"
+
+
+
+namespace nv
+{
+    namespace HalfEdge { class Mesh; }
+
+    struct ChartBuildData;
+
+    struct AtlasBuilder
+    {
+        AtlasBuilder(const HalfEdge::Mesh * m);
+        ~AtlasBuilder();
+
+        void markUnchartedFaces(const Array<uint> & unchartedFaces);
+
+        void computeShortestPaths();
+
+        void placeSeeds(float threshold, uint maxSeedCount);
+        void createRandomChart(float threshold);
+
+        void addFaceToChart(ChartBuildData * chart, uint f, bool recomputeProxy=false);
+
+        bool growCharts(float threshold, uint faceCount);
+        bool growChart(ChartBuildData * chart, float threshold, uint faceCount);
+
+        void resetCharts();
+
+        void updateCandidates(ChartBuildData * chart, uint face);
+
+        void updateProxies();
+        void updateProxy(ChartBuildData * chart);
+
+        bool relocateSeeds();
+        bool relocateSeed(ChartBuildData * chart);
+
+        void updatePriorities(ChartBuildData * chart);
+
+        float evaluatePriority(ChartBuildData * chart, uint face);
+        float evaluateProxyFitMetric(ChartBuildData * chart, uint face);
+        float evaluateDistanceToBoundary(ChartBuildData * chart, uint face);
+        float evaluateDistanceToSeed(ChartBuildData * chart, uint face);
+        float evaluateRoundnessMetric(ChartBuildData * chart, uint face, float newBoundaryLength, float newChartArea);
+        float evaluateStraightnessMetric(ChartBuildData * chart, uint face);
+
+        float evaluateNormalSeamMetric(ChartBuildData * chart, uint f);
+        float evaluateTextureSeamMetric(ChartBuildData * chart, uint f);
+        float evaluateSeamMetric(ChartBuildData * chart, uint f);
+
+        float evaluateChartArea(ChartBuildData * chart, uint f);
+        float evaluateBoundaryLength(ChartBuildData * chart, uint f);
+        Vector3 evaluateChartNormalSum(ChartBuildData * chart, uint f);
+        Vector3 evaluateChartCentroidSum(ChartBuildData * chart, uint f);
+
+        Vector3 computeChartCentroid(const ChartBuildData * chart);
+
+
+        void fillHoles(float threshold);
+        void mergeCharts();
+
+        // @@ Cleanup.
+        struct Candidate {
+            uint face;
+            ChartBuildData * chart;
+            float metric;
+        };
+
+        const Candidate & getBestCandidate() const;
+        void removeCandidate(uint f);
+        void updateCandidate(ChartBuildData * chart, uint f, float metric);
+
+        void mergeChart(ChartBuildData * owner, ChartBuildData * chart, float sharedBoundaryLength);
+
+
+        uint chartCount() const { return chartArray.count(); }
+        const Array<uint> & chartFaces(uint i) const;
+
+        const HalfEdge::Mesh * mesh;
+        uint facesLeft;
+        Array<int> faceChartArray;
+        Array<ChartBuildData *> chartArray;
+        Array<float> shortestPaths;
+
+        Array<float> edgeLengths;
+        Array<float> faceAreas;
+
+        Array<Candidate> candidateArray; //
+        Array<uint> faceCandidateArray; // Map face index to candidate index.
+
+        MTRand rand;
+
+        SegmentationSettings settings;
+    };
+
+} // nv namespace
+
+#endif // NV_MESH_ATLASBUILDER_H
diff --git a/thirdparty/thekla_atlas/nvmesh/param/AtlasPacker.cpp b/thirdparty/thekla_atlas/nvmesh/param/AtlasPacker.cpp
new file mode 100644
index 0000000000..f2156899ae
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/AtlasPacker.cpp
@@ -0,0 +1,1379 @@
+// This code is in the public domain -- castano@gmail.com
+
+#include "nvmesh.h" // pch
+
+#include "AtlasPacker.h"
+#include "nvmesh/halfedge/Vertex.h"
+#include "nvmesh/halfedge/Face.h"
+#include "nvmesh/param/Atlas.h"
+#include "nvmesh/param/Util.h"
+#include "nvmesh/raster/Raster.h"
+
+#include "nvmath/Vector.inl"
+#include "nvmath/ConvexHull.h"
+#include "nvmath/Color.h"
+#include "nvmath/ftoi.h"
+
+#include "nvcore/StrLib.h" // debug
+#include "nvcore/StdStream.h" // fileOpen
+
+#include <float.h> // FLT_MAX
+#include <limits.h> // UINT_MAX
+
+using namespace nv;
+
+#define DEBUG_OUTPUT 0
+
+#if DEBUG_OUTPUT
+
+#include "nvimage/ImageIO.h"
+
+namespace
+{
+    const uint TGA_TYPE_GREY = 3;
+    const uint TGA_TYPE_RGB = 2;
+    const uint TGA_ORIGIN_UPPER = 0x20;
+
+#pragma pack(push, 1)
+    struct TgaHeader {
+	    uint8	id_length;
+	    uint8	colormap_type;
+	    uint8	image_type;
+	    uint16	colormap_index;
+	    uint16	colormap_length;
+	    uint8	colormap_size;
+	    uint16	x_origin;
+	    uint16	y_origin;
+	    uint16	width;
+	    uint16	height;
+	    uint8	pixel_size;
+	    uint8	flags;
+
+	    enum { Size = 18 };		//const static int SIZE = 18;
+    };
+#pragma pack(pop)
+
+    static void outputDebugBitmap(const char * fileName, const BitMap & bitmap, int w, int h)
+    {
+        FILE * fp = fileOpen(fileName, "wb");
+        if (fp == NULL) return;
+        
+        nvStaticCheck(sizeof(TgaHeader) == TgaHeader::Size);
+	    TgaHeader tga;
+	    tga.id_length = 0;
+	    tga.colormap_type = 0;
+	    tga.image_type = TGA_TYPE_GREY;
+
+	    tga.colormap_index = 0;
+	    tga.colormap_length = 0;
+	    tga.colormap_size = 0;
+
+	    tga.x_origin = 0;
+	    tga.y_origin = 0;
+        tga.width = w;
+        tga.height = h;
+	    tga.pixel_size = 8;
+	    tga.flags = TGA_ORIGIN_UPPER;
+
+        fwrite(&tga, sizeof(TgaHeader), 1, fp);
+
+		for (int j = 0; j < h; j++) {
+            for (int i = 0; i < w; i++) {
+                uint8 color = bitmap.bitAt(i, j) ? 0xFF : 0x0;
+                fwrite(&color, 1, 1, fp);
+            }
+		}
+
+        fclose(fp);
+    }
+
+    static void outputDebugImage(const char * fileName, const Image & bitmap, int w, int h)
+    {
+        FILE * fp = fileOpen(fileName, "wb");
+        if (fp == NULL) return;
+        
+        nvStaticCheck(sizeof(TgaHeader) == TgaHeader::Size);
+	    TgaHeader tga;
+	    tga.id_length = 0;
+	    tga.colormap_type = 0;
+        tga.image_type = TGA_TYPE_RGB;
+
+	    tga.colormap_index = 0;
+	    tga.colormap_length = 0;
+	    tga.colormap_size = 0;
+
+	    tga.x_origin = 0;
+	    tga.y_origin = 0;
+        tga.width = w;
+        tga.height = h;
+	    tga.pixel_size = 24;
+	    tga.flags = TGA_ORIGIN_UPPER;
+
+        fwrite(&tga, sizeof(TgaHeader), 1, fp);
+
+		for (int j = 0; j < h; j++) {
+            for (int i = 0; i < w; i++) {
+                Color32 color = bitmap.pixel(i, j);
+                fwrite(&color.r, 1, 1, fp);
+                fwrite(&color.g, 1, 1, fp);
+                fwrite(&color.b, 1, 1, fp);
+            }
+		}
+
+        fclose(fp);
+    }
+}
+
+#endif // DEBUG_OUTPUT
+
+inline int align(int x, int a) {
+    //return a * ((x + a - 1) / a);
+    //return (x + a - 1) & -a;
+    return (x + a - 1) & ~(a - 1);
+}
+
+inline bool isAligned(int x, int a) {
+    return (x & (a - 1)) == 0;
+}
+
+
+
+AtlasPacker::AtlasPacker(Atlas * atlas) : m_atlas(atlas), m_bitmap(256, 256)
+{
+    m_width = 0;
+    m_height = 0;
+    
+    m_debug_bitmap.allocate(256, 256);
+    m_debug_bitmap.fill(Color32(0,0,0,0));
+}
+
+AtlasPacker::~AtlasPacker()
+{
+}
+
+// This should compute convex hull and use rotating calipers to find the best box. Currently it uses a brute force method.
+static void computeBoundingBox(Chart * chart, Vector2 * majorAxis, Vector2 * minorAxis, Vector2 * minCorner, Vector2 * maxCorner)
+{
+    // Compute list of boundary points.
+    Array<Vector2> points(16);
+
+    HalfEdge::Mesh * mesh = chart->chartMesh();
+    const uint vertexCount = mesh->vertexCount();
+
+    for (uint i = 0; i < vertexCount; i++) {
+        HalfEdge::Vertex * vertex = mesh->vertexAt(i);
+        if (vertex->isBoundary()) {
+            points.append(vertex->tex);
+        }
+    }
+
+    // This is not valid anymore. The chart mesh may have multiple boundaries!
+    /*const HalfEdge::Vertex * vertex = findBoundaryVertex(chart->chartMesh());
+
+    // Traverse boundary.
+    const HalfEdge::Edge * const firstEdge = vertex->edge();
+    const HalfEdge::Edge * edge = firstEdge;
+    do {
+        vertex = edge->vertex();
+
+        nvDebugCheck (vertex->isBoundary());
+        points.append(vertex->tex);
+
+        edge = edge->next();
+    } while (edge != firstEdge);*/
+
+#if 1
+    Array<Vector2> hull;
+    
+    convexHull(points, hull, 0.00001f);
+
+    // @@ Ideally I should use rotating calipers to find the best box. Using brute force for now.
+
+    float best_area = FLT_MAX;
+    Vector2 best_min;
+    Vector2 best_max;
+    Vector2 best_axis;
+
+    const uint hullCount = hull.count();
+    for (uint i = 0, j = hullCount-1; i < hullCount; j = i, i++) {
+
+        if (equal(hull[i], hull[j])) {
+            continue;
+        }
+
+        Vector2 axis = normalize(hull[i] - hull[j], 0.0f);
+        nvDebugCheck(isFinite(axis));
+
+        // Compute bounding box.
+        Vector2 box_min(FLT_MAX, FLT_MAX);
+        Vector2 box_max(-FLT_MAX, -FLT_MAX);
+
+        for (uint v = 0; v < hullCount; v++) {
+
+           Vector2 point = hull[v];
+
+           float x = dot(axis, point);
+           if (x < box_min.x) box_min.x = x;
+           if (x > box_max.x) box_max.x = x;
+
+           float y = dot(Vector2(-axis.y, axis.x), point);
+           if (y < box_min.y) box_min.y = y;
+           if (y > box_max.y) box_max.y = y;
+        }
+    
+        // Compute box area.
+        float area = (box_max.x - box_min.x) * (box_max.y - box_min.y);
+
+        if (area < best_area) {
+            best_area = area;
+            best_min = box_min;
+            best_max = box_max;
+            best_axis = axis;
+        }
+    }
+
+    // Make sure the box contains all the input points since the convex hull is not 100% accurate.
+    /*const uint pointCount = points.count();
+    for (uint v = 0; v < pointCount; v++) {
+
+        Vector2 point = points[v];
+
+        float x = dot(best_axis, point);
+        if (x < best_min.x) best_min.x = x;
+
+        float y = dot(Vector2(-best_axis.y, best_axis.x), point);
+        if (y < best_min.y) best_min.y = y;
+    }*/
+
+    // Consider all points, not only boundary points, in case the input chart is malformed.
+    for (uint i = 0; i < vertexCount; i++) {
+        HalfEdge::Vertex * vertex = mesh->vertexAt(i);
+        Vector2 point = vertex->tex;
+
+        float x = dot(best_axis, point);
+        if (x < best_min.x) best_min.x = x;
+        if (x > best_max.x) best_max.x = x;
+
+        float y = dot(Vector2(-best_axis.y, best_axis.x), point);
+        if (y < best_min.y) best_min.y = y;
+        if (y > best_max.y) best_max.y = y;
+    }
+
+    *majorAxis = best_axis;
+    *minorAxis = Vector2(-best_axis.y, best_axis.x);
+    *minCorner = best_min;
+    *maxCorner = best_max;
+
+#else
+    // Approximate implementation: try 16 different directions and keep the best.
+
+    const uint N = 16;
+    Vector2 axis[N];
+
+    float minAngle = 0;
+    float maxAngle = PI / 2;
+
+    int best;
+    Vector2 mins[N];
+    Vector2 maxs[N];
+
+    const int iterationCount = 1;
+    for (int j = 0; j < iterationCount; j++)
+    {
+        // Init predefined directions.
+        for (int i = 0; i < N; i++)
+        {
+            float angle = lerp(minAngle, maxAngle, float(i)/N);
+            axis[i].set(cosf(angle), sinf(angle));
+        }
+
+        // Compute box for each direction.
+        for (int i = 0; i < N; i++)
+        {
+            mins[i].set(FLT_MAX, FLT_MAX);
+            maxs[i].set(-FLT_MAX, -FLT_MAX);
+        }
+
+        for (uint p = 0; p < points.count(); p++)
+        {
+            Vector2 point = points[p];
+
+            for (int i = 0; i < N; i++)
+            {
+               float x = dot(axis[i], point);
+               if (x < mins[i].x) mins[i].x = x;
+               if (x > maxs[i].x) maxs[i].x = x;
+
+               float y = dot(Vector2(-axis[i].y, axis[i].x), point);
+               if (y < mins[i].y) mins[i].y = y;
+               if (y > maxs[i].y) maxs[i].y = y;
+            }
+        }
+
+        // Find box with minimum area.
+        best = -1;
+        int second_best = -1;
+        float best_area = FLT_MAX;
+        float second_best_area = FLT_MAX;
+        
+        for (int i = 0; i < N; i++)
+        {
+            float area = (maxs[i].x - mins[i].x) * (maxs[i].y - mins[i].y);
+
+            if (area < best_area)
+            {
+                second_best_area = best_area;
+                second_best = best;
+
+                best_area = area;
+                best = i;
+            }
+            else if (area < second_best_area)
+            {
+                second_best_area = area;
+                second_best = i;
+            }
+        }
+        nvDebugCheck(best != -1);
+        nvDebugCheck(second_best != -1);
+        nvDebugCheck(best != second_best);
+
+        if (j != iterationCount-1)
+        {
+            // Handle wrap-around during the first iteration.
+            if (j == 0) {
+                if (best == 0 && second_best == N-1) best = N;
+                if (best == N-1 && second_best == 0) second_best = N;
+            }
+
+            if (best < second_best) swap(best, second_best);
+
+            // Update angles.
+            float deltaAngle = (maxAngle - minAngle) / N;
+            maxAngle = minAngle + (best - 0.5f)  * deltaAngle;
+            minAngle = minAngle + (second_best + 0.5f) * deltaAngle;
+        }
+    }
+
+    // Compute major and minor axis, and origin.
+    *majorAxis = axis[best];
+    *minorAxis = Vector2(-axis[best].y, axis[best].x);
+    *origin = mins[best];
+
+    // @@ If the parameterization is invalid, we could have an interior vertex outside the boundary.
+    // @@ In that case the returned bounding box would be incorrect. Compute updated bounds here.
+    /*for (uint p = 0; p < points.count(); p++)
+    {
+        Vector2 point = points[p];
+
+        for (int i = 0; i < N; i++)
+        {
+           float x = dot(*majorAxis, point);
+           float y = dot(*minorAxis, point);
+        }
+    }*/
+#endif
+}
+
+
+void AtlasPacker::packCharts(int quality, float texelsPerUnit, bool blockAligned, bool conservative)
+{
+    const uint chartCount = m_atlas->chartCount();
+    if (chartCount == 0) return;
+
+    Array<float> chartOrderArray;
+    chartOrderArray.resize(chartCount);
+
+    Array<Vector2> chartExtents;
+    chartExtents.resize(chartCount);
+    
+    float meshArea = 0;
+    for (uint c = 0; c < chartCount; c++)
+    {
+        Chart * chart = m_atlas->chartAt(c);
+        
+        if (!chart->isVertexMapped() && !chart->isDisk()) {
+            chartOrderArray[c] = 0;
+
+            // Skip non-disks.
+            continue;
+        }
+
+        Vector2 extents(0.0f);
+
+        if (chart->isVertexMapped()) {
+            // Let's assume vertex maps are arranged in a rectangle.
+            //HalfEdge::Mesh * mesh = chart->chartMesh();
+
+            // Arrange vertices in a rectangle.
+            extents.x = float(chart->vertexMapWidth);
+            extents.y = float(chart->vertexMapHeight);
+        }
+        else {
+            // Compute surface area to sort charts.
+            float chartArea = chart->computeSurfaceArea();
+            meshArea += chartArea;
+            //chartOrderArray[c] = chartArea;
+
+            // Compute chart scale
+            float parametricArea = fabs(chart->computeParametricArea());    // @@ There doesn't seem to be anything preventing parametric area to be negative.
+            if (parametricArea < NV_EPSILON) {
+                // When the parametric area is too small we use a rough approximation to prevent divisions by very small numbers.
+                Vector2 bounds = chart->computeParametricBounds();
+                parametricArea = bounds.x * bounds.y;
+            }
+            float scale = (chartArea / parametricArea) * texelsPerUnit;
+            if (parametricArea == 0) // < NV_EPSILON)
+            {
+                scale = 0;
+            }
+            nvCheck(isFinite(scale));
+
+            // Compute bounding box of chart.
+            Vector2 majorAxis, minorAxis, origin, end;
+            computeBoundingBox(chart, &majorAxis, &minorAxis, &origin, &end);
+
+            nvCheck(isFinite(majorAxis) && isFinite(minorAxis) && isFinite(origin));
+            
+            // Sort charts by perimeter. @@ This is sometimes producing somewhat unexpected results. Is this right?
+            //chartOrderArray[c] = ((end.x - origin.x) + (end.y - origin.y)) * scale;
+
+            // Translate, rotate and scale vertices. Compute extents.
+            HalfEdge::Mesh * mesh = chart->chartMesh();
+            const uint vertexCount = mesh->vertexCount();
+            for (uint i = 0; i < vertexCount; i++)
+            {
+                HalfEdge::Vertex * vertex = mesh->vertexAt(i);
+
+                //Vector2 t = vertex->tex - origin;
+                Vector2 tmp;
+                tmp.x = dot(vertex->tex, majorAxis);
+                tmp.y = dot(vertex->tex, minorAxis);
+                tmp -= origin;
+                tmp *= scale;
+                if (tmp.x < 0 || tmp.y < 0) {
+                    nvDebug("tmp: %f %f\n", tmp.x, tmp.y);
+                    nvDebug("scale: %f\n", scale);
+                    nvDebug("origin: %f %f\n", origin.x, origin.y);
+                    nvDebug("majorAxis: %f %f\n", majorAxis.x, majorAxis.y);
+                    nvDebug("minorAxis: %f %f\n", minorAxis.x, minorAxis.y);
+                    nvDebugBreak();
+                }
+                //nvCheck(tmp.x >= 0 && tmp.y >= 0);
+
+                vertex->tex = tmp;
+
+				nvCheck(isFinite(vertex->tex.x) && isFinite(vertex->tex.y));
+
+                extents = max(extents, tmp);
+            }
+            nvDebugCheck(extents.x >= 0 && extents.y >= 0);
+
+            // Limit chart size.
+            if (extents.x > 1024 || extents.y > 1024) {
+                float limit = max(extents.x, extents.y);
+
+                scale = 1024 / (limit + 1);
+
+                for (uint i = 0; i < vertexCount; i++)
+                {
+                    HalfEdge::Vertex * vertex = mesh->vertexAt(i);
+                    vertex->tex *= scale;
+                }
+
+                extents *= scale;
+
+                nvDebugCheck(extents.x <= 1024 && extents.y <= 1024);
+            }
+
+
+            // Scale the charts to use the entire texel area available. So, if the width is 0.1 we could scale it to 1 without increasing the lightmap usage and making a better 
+            // use of it. In many cases this also improves the look of the seams, since vertices on the chart boundaries have more chances of being aligned with the texel centers.
+
+            float scale_x = 1.0f;
+            float scale_y = 1.0f;
+
+            float divide_x = 1.0f;
+            float divide_y = 1.0f;
+
+            if (extents.x > 0) {
+                int cw = ftoi_ceil(extents.x);
+
+                if (blockAligned) {
+                    // Align all chart extents to 4x4 blocks, but taking padding into account.
+                    if (conservative) {
+                        cw = align(cw + 2, 4) - 2;
+                    }
+                    else {
+                        cw = align(cw + 1, 4) - 1;
+                    }
+                }
+
+                scale_x = (float(cw) - NV_EPSILON);
+                divide_x = extents.x;
+                extents.x = float(cw);
+            }
+
+            if (extents.y > 0) {
+                int ch = ftoi_ceil(extents.y);
+
+                if (blockAligned) {
+                    // Align all chart extents to 4x4 blocks, but taking padding into account.
+                    if (conservative) {
+                        ch = align(ch + 2, 4) - 2;
+                    }
+                    else {
+                        ch = align(ch + 1, 4) - 1;
+                    }
+                }
+
+                scale_y = (float(ch) - NV_EPSILON);
+                divide_y = extents.y;
+                extents.y = float(ch);
+            }
+
+            for (uint v = 0; v < vertexCount; v++) {
+                HalfEdge::Vertex * vertex = mesh->vertexAt(v);
+
+                vertex->tex.x /= divide_x;
+                vertex->tex.y /= divide_y;
+                vertex->tex.x *= scale_x;
+                vertex->tex.y *= scale_y;
+
+				nvCheck(isFinite(vertex->tex.x) && isFinite(vertex->tex.y));
+            }
+        }
+
+        chartExtents[c] = extents;
+
+        // Sort charts by perimeter.
+        chartOrderArray[c] = extents.x + extents.y;
+    }
+
+    // @@ We can try to improve compression of small charts by sorting them by proximity like we do with vertex samples.
+    // @@ How to do that? One idea: compute chart centroid, insert into grid, compute morton index of the cell, sort based on morton index.
+    // @@ We would sort by morton index, first, then quantize the chart sizes, so that all small charts have the same size, and sort by size preserving the morton order.
+
+    //nvDebug("Sorting charts.\n");
+
+    // Sort charts by area.
+    m_radix.sort(chartOrderArray);
+    const uint32 * ranks = m_radix.ranks();
+
+    // Estimate size of the map based on the mesh surface area and given texel scale.
+    float texelCount = meshArea * square(texelsPerUnit) / 0.75f; // Assume 75% utilization.
+    if (texelCount < 1) texelCount = 1;
+    uint approximateExtent = nextPowerOfTwo(uint(sqrtf(texelCount)));
+
+    //nvDebug("Init bitmap.\n");
+
+    // @@ Pack all charts smaller than a texel into a compact rectangle.
+    // @@ Start considering only 1x1 charts. Extend to 1xn charts later.
+
+    /*for (uint i = 0; i < chartCount; i++)
+    {
+        uint c = ranks[chartCount - i - 1]; // largest chart first
+
+        Chart * chart = m_atlas->chartAt(c);
+
+        if (!chart->isDisk()) continue;
+
+        if (iceil(chartExtents[c].x) == 1 && iceil(chartExtents[c].x) == 1) {
+            // @@ Add to 
+        }
+    }*/
+
+
+
+    // Init bit map.
+    m_bitmap.clearAll();
+    if (approximateExtent > m_bitmap.width()) {
+        m_bitmap.resize(approximateExtent, approximateExtent, false);
+        m_debug_bitmap.resize(approximateExtent, approximateExtent);
+        m_debug_bitmap.fill(Color32(0,0,0,0));
+    }
+
+    
+    int w = 0;
+    int h = 0;
+
+#if 1
+    // Add sorted charts to bitmap.
+    for (uint i = 0; i < chartCount; i++)
+    {
+        uint c = ranks[chartCount - i - 1]; // largest chart first
+
+        Chart * chart = m_atlas->chartAt(c);
+
+        if (!chart->isVertexMapped() && !chart->isDisk()) continue;
+
+        //float scale_x = 1;
+        //float scale_y = 1;
+
+        BitMap chart_bitmap;
+
+        if (chart->isVertexMapped()) {
+            // Init all bits to 1.
+            chart_bitmap.resize(ftoi_ceil(chartExtents[c].x), ftoi_ceil(chartExtents[c].y), /*initValue=*/true);
+
+            // @@ Another alternative would be to try to map each vertex to a different texel trying to fill all the available unused texels.
+        }
+        else {
+            // @@ Add special cases for dot and line charts. @@ Lightmap rasterizer also needs to handle these special cases.
+            // @@ We could also have a special case for chart quads. If the quad surface <= 4 texels, align vertices with texel centers and do not add padding. May be very useful for foliage.
+
+            // @@ In general we could reduce the padding of all charts by one texel by using a rasterizer that takes into account the 2-texel footprint of the tent bilinear filter. For example,
+            // if we have a chart that is less than 1 texel wide currently we add one texel to the left and one texel to the right creating a 3-texel-wide bitmap. However, if we know that the 
+            // chart is only 1 texel wide we could align it so that it only touches the footprint of two texels:
+
+            //      |   |      <- Touches texels 0, 1 and 2.
+            //    |   |        <- Only touches texels 0 and 1.
+            // \   \ / \ /   /
+            //  \   X   X   /
+            //   \ / \ / \ /
+            //    V   V   V
+            //    0   1   2
+
+            if (conservative) {
+                // Init all bits to 0.
+                chart_bitmap.resize(ftoi_ceil(chartExtents[c].x) + 2, ftoi_ceil(chartExtents[c].y) + 2, /*initValue=*/false);  // + 2 to add padding on both sides.
+
+                // Rasterize chart and dilate.
+                drawChartBitmapDilate(chart, &chart_bitmap, /*padding=*/1);
+            }
+            else {
+                // Init all bits to 0.
+                chart_bitmap.resize(ftoi_ceil(chartExtents[c].x) + 1, ftoi_ceil(chartExtents[c].y) + 1, /*initValue=*/false);  // Add half a texels on each side.
+
+                // Rasterize chart and dilate.
+                drawChartBitmap(chart, &chart_bitmap, Vector2(1), Vector2(0.5));
+            }
+        }
+
+        int best_x, best_y;
+        int best_cw, best_ch;   // Includes padding now.
+        int best_r;
+        findChartLocation(quality, &chart_bitmap, chartExtents[c], w, h, &best_x, &best_y, &best_cw, &best_ch, &best_r);
+        
+        /*if (w < best_x + best_cw || h < best_y + best_ch)
+        {
+            nvDebug("Resize extents to (%d, %d).\n", best_x + best_cw, best_y + best_ch);
+        }*/
+
+        // Update parametric extents.
+        w = max(w, best_x + best_cw);
+        h = max(h, best_y + best_ch);
+        
+        w = align(w, 4);
+        h = align(h, 4);
+
+        // Resize bitmap if necessary.
+        if (uint(w) > m_bitmap.width() || uint(h) > m_bitmap.height())
+        {
+            //nvDebug("Resize bitmap (%d, %d).\n", nextPowerOfTwo(w), nextPowerOfTwo(h));
+            m_bitmap.resize(nextPowerOfTwo(U32(w)), nextPowerOfTwo(U32(h)), false);
+            m_debug_bitmap.resize(nextPowerOfTwo(U32(w)), nextPowerOfTwo(U32(h)));
+        }
+
+        //nvDebug("Add chart at (%d, %d).\n", best_x, best_y);
+
+        addChart(&chart_bitmap, w, h, best_x, best_y, best_r, /*debugOutput=*/NULL);
+
+        // IC: Output chart again to debug bitmap.
+        if (chart->isVertexMapped()) {
+            addChart(&chart_bitmap, w, h, best_x, best_y, best_r, &m_debug_bitmap);
+        }
+        else {
+            addChart(chart, w, h, best_x, best_y, best_r, &m_debug_bitmap);
+        }
+
+        //float best_angle = 2 * PI * best_r;
+
+        // Translate and rotate chart texture coordinates.
+        HalfEdge::Mesh * mesh = chart->chartMesh();
+        const uint vertexCount = mesh->vertexCount();
+        for (uint v = 0; v < vertexCount; v++)
+        {
+            HalfEdge::Vertex * vertex = mesh->vertexAt(v);
+
+            Vector2 t = vertex->tex;
+            if (best_r) swap(t.x, t.y);
+            //vertex->tex.x = best_x + t.x * cosf(best_angle) - t.y * sinf(best_angle);
+            //vertex->tex.y = best_y + t.x * sinf(best_angle) + t.y * cosf(best_angle);
+
+            vertex->tex.x = best_x + t.x + 0.5f;
+            vertex->tex.y = best_y + t.y + 0.5f;
+
+            nvCheck(vertex->tex.x >= 0 && vertex->tex.y >= 0);
+			nvCheck(isFinite(vertex->tex.x) && isFinite(vertex->tex.y));
+        }
+
+#if DEBUG_OUTPUT && 0
+        StringBuilder fileName;
+        fileName.format("debug_packer_%d.tga", i);
+        //outputDebugBitmap(fileName.str(), m_bitmap, w, h);
+        outputDebugImage(fileName.str(), m_debug_bitmap, w, h);
+#endif
+    }
+
+#else // 0
+
+    // Add sorted charts to bitmap.
+    for (uint i = 0; i < chartCount; i++)
+    {
+        uint c = ranks[chartCount - i - 1]; // largest chart first
+
+        Chart * chart = m_atlas->chartAt(c);
+
+        if (!chart->isDisk()) continue;
+
+        Vector2 scale(1, 1);
+
+#if 0 // old method.
+        //m_padding_x = 2*padding;
+        //m_padding_y = 2*padding;
+#else
+        //m_padding_x = 0; //padding;
+        //m_padding_y = 0; //padding;
+#endif
+
+        int bw = ftoi_ceil(chartExtents[c].x + 1);
+        int bh = ftoi_ceil(chartExtents[c].y + 1);
+
+        if (chartExtents[c].x < 1.0f) {
+            scale.x = 0.01f; // @@ Ideally we would like to scale it to 0, but then our rasterizer would not touch any pixels.
+            bw = 1;
+        }
+        if (chartExtents[c].y < 1.0f) {
+            scale.y = 0.01f;
+            bh = 1;
+        }
+
+        //BitMap chart_bitmap(iceil(chartExtents[c].x) + 1 + m_padding_x * 2, iceil(chartExtents[c].y) + 1 + m_padding_y * 2);
+        //BitMap chart_bitmap(ftoi_ceil(chartExtents[c].x/2)*2, ftoi_ceil(chartExtents[c].y/2)*2);
+        BitMap chart_bitmap(bw, bh);
+        chart_bitmap.clearAll();
+        
+        Vector2 offset;
+        offset.x = 0; // (chart_bitmap.width() - chartExtents[c].x) * 0.5f;
+        offset.y = 0; // (chart_bitmap.height() - chartExtents[c].y) * 0.5f;
+
+        drawChartBitmap(chart, &chart_bitmap, scale, offset);
+
+        int best_x, best_y;
+        int best_cw, best_ch;
+        int best_r;
+        findChartLocation(quality, &chart_bitmap, chartExtents[c], w, h, &best_x, &best_y, &best_cw, &best_ch, &best_r);
+
+        /*if (w < best_x + best_cw || h < best_y + best_ch)
+        {
+            nvDebug("Resize extents to (%d, %d).\n", best_x + best_cw, best_y + best_ch);
+        }*/
+
+        // Update parametric extents.
+        w = max(w, best_x + best_cw);
+        h = max(h, best_y + best_ch);
+
+        // Resize bitmap if necessary.
+        if (uint(w) > m_bitmap.width() || uint(h) > m_bitmap.height())
+        {
+            //nvDebug("Resize bitmap (%d, %d).\n", nextPowerOfTwo(w), nextPowerOfTwo(h));
+            m_bitmap.resize(nextPowerOfTwo(w), nextPowerOfTwo(h), false);
+            m_debug_bitmap.resize(nextPowerOfTwo(w), nextPowerOfTwo(h));
+        }
+
+        //nvDebug("Add chart at (%d, %d).\n", best_x, best_y);
+
+#if 0 // old method.
+#if _DEBUG
+        checkCanAddChart(chart, w, h, best_x, best_y, best_r);
+#endif
+
+        // Add chart.
+        addChart(chart, w, h, best_x, best_y, best_r);
+#else
+        // Add chart reusing its bitmap.
+        addChart(&chart_bitmap, w, h, best_x, best_y, best_r);
+#endif
+
+        //float best_angle = 2 * PI * best_r;
+
+        // Translate and rotate chart texture coordinates.
+        HalfEdge::Mesh * mesh = chart->chartMesh();
+        const uint vertexCount = mesh->vertexCount();
+        for (uint v = 0; v < vertexCount; v++)
+        {
+            HalfEdge::Vertex * vertex = mesh->vertexAt(v);
+
+            Vector2 t = vertex->tex * scale + offset;
+            if (best_r) swap(t.x, t.y);
+            //vertex->tex.x = best_x + t.x * cosf(best_angle) - t.y * sinf(best_angle);
+            //vertex->tex.y = best_y + t.x * sinf(best_angle) + t.y * cosf(best_angle);
+            vertex->tex.x = best_x + t.x + 0.5f;
+            vertex->tex.y = best_y + t.y + 0.5f;
+
+            nvCheck(vertex->tex.x >= 0 && vertex->tex.y >= 0);
+        }
+
+#if DEBUG_OUTPUT && 0
+        StringBuilder fileName;
+        fileName.format("debug_packer_%d.tga", i);
+        //outputDebugBitmap(fileName.str(), m_bitmap, w, h);
+        outputDebugImage(fileName.str(), m_debug_bitmap, w, h);
+#endif
+    }
+
+#endif // 0
+
+    //w -= padding - 1; // Leave one pixel border!
+    //h -= padding - 1;
+
+    m_width = max(0, w);
+    m_height = max(0, h);
+
+    nvCheck(isAligned(m_width, 4));
+    nvCheck(isAligned(m_height, 4));
+
+    m_debug_bitmap.resize(m_width, m_height);
+    m_debug_bitmap.setFormat(Image::Format_ARGB);
+
+#if DEBUG_OUTPUT
+    //outputDebugBitmap("debug_packer_final.tga", m_bitmap, w, h);
+    //outputDebugImage("debug_packer_final.tga", m_debug_bitmap, w, h);
+    ImageIO::save("debug_packer_final.tga", &m_debug_bitmap);
+#endif
+}
+
+
+// IC: Brute force is slow, and random may take too much time to converge. We start inserting large charts in a small atlas. Using brute force is lame, because most of the space 
+// is occupied at this point. At the end we have many small charts and a large atlas with sparse holes. Finding those holes randomly is slow. A better approach would be to 
+// start stacking large charts as if they were tetris pieces. Once charts get small try to place them randomly. It may be interesting to try a intermediate strategy, first try 
+// along one axis and then try exhaustively along that axis.
+void AtlasPacker::findChartLocation(int quality, const BitMap * bitmap, Vector2::Arg extents, int w, int h, int * best_x, int * best_y, int * best_w, int * best_h, int * best_r)
+{
+    int attempts = 256;
+    if (quality == 1) attempts = 4096;
+    if (quality == 2) attempts = 2048;
+    if (quality == 3) attempts = 1024;
+    if (quality == 4) attempts = 512;
+
+    if (quality == 0 || w*h < attempts)
+    {
+        findChartLocation_bruteForce(bitmap, extents, w, h, best_x, best_y, best_w, best_h, best_r);
+    }
+    else
+    {
+        findChartLocation_random(bitmap, extents, w, h, best_x, best_y, best_w, best_h, best_r, attempts);
+    }
+}
+
+#define BLOCK_SIZE 4
+
+void AtlasPacker::findChartLocation_bruteForce(const BitMap * bitmap, Vector2::Arg extents, int w, int h, int * best_x, int * best_y, int * best_w, int * best_h, int * best_r)
+{
+    int best_metric = INT_MAX;
+
+    // Try two different orientations.
+    for (int r = 0; r < 2; r++)
+    {
+        int cw = bitmap->width();
+        int ch = bitmap->height();
+        if (r & 1) swap(cw, ch);
+
+        for (int y = 0; y <= h + 1; y += BLOCK_SIZE) // + 1 to extend atlas in case atlas full.
+        {
+            for (int x = 0; x <= w + 1; x += BLOCK_SIZE) // + 1 not really necessary here.
+            {
+                // Early out.
+                int area = max(w, x+cw) * max(h, y+ch);
+                //int perimeter = max(w, x+cw) + max(h, y+ch);
+                int extents = max(max(w, x+cw), max(h, y+ch));
+
+                int metric = extents*extents + area;
+
+                if (metric > best_metric) {
+                    continue;
+                }
+                if (metric == best_metric && max(x, y) >= max(*best_x, *best_y)) {
+                    // If metric is the same, pick the one closest to the origin.
+                    continue;
+                }
+
+                if (canAddChart(bitmap, w, h, x, y, r))
+                {
+                    best_metric = metric;
+                    *best_x = x;
+                    *best_y = y;
+                    *best_w = cw;
+                    *best_h = ch;
+                    *best_r = r;
+
+                    if (area == w*h)
+                    {
+                        // Chart is completely inside, do not look at any other location.
+                        goto done;
+                    }
+                }
+            }
+        }
+    }
+
+done:
+    nvDebugCheck (best_metric != INT_MAX);
+}
+
+
+void AtlasPacker::findChartLocation_random(const BitMap * bitmap, Vector2::Arg extents, int w, int h, int * best_x, int * best_y, int * best_w, int * best_h, int * best_r, int minTrialCount)
+{
+    int best_metric = INT_MAX;
+
+    for (int i = 0; i < minTrialCount || best_metric == INT_MAX; i++)
+    {
+        int r = m_rand.getRange(1);
+        int x = m_rand.getRange(w + 1); // + 1 to extend atlas in case atlas full. We may want to use a higher number to increase probability of extending atlas.
+        int y = m_rand.getRange(h + 1); // + 1 to extend atlas in case atlas full.
+
+        x = align(x, BLOCK_SIZE);
+        y = align(y, BLOCK_SIZE);
+
+        int cw = bitmap->width();
+        int ch = bitmap->height();
+        if (r & 1) swap(cw, ch);
+
+        // Early out.
+        int area = max(w, x+cw) * max(h, y+ch);
+        //int perimeter = max(w, x+cw) + max(h, y+ch);
+        int extents = max(max(w, x+cw), max(h, y+ch));
+
+        int metric = extents*extents + area;
+
+        if (metric > best_metric) {
+            continue;
+        }
+        if (metric == best_metric && min(x, y) > min(*best_x, *best_y)) {
+            // If metric is the same, pick the one closest to the origin.
+            continue;
+        }
+
+        if (canAddChart(bitmap, w, h, x, y, r))
+        {
+            best_metric = metric;
+            *best_x = x;
+            *best_y = y;
+            *best_w = cw;
+            *best_h = ch;
+            *best_r = r;
+
+            if (area == w*h)
+            {
+                // Chart is completely inside, do not look at any other location.
+                break;
+            }
+        }
+    }
+}
+
+
+void AtlasPacker::drawChartBitmapDilate(const Chart * chart, BitMap * bitmap, int padding)
+{
+    const int w = bitmap->width();
+    const int h = bitmap->height();
+    const Vector2 extents = Vector2(float(w), float(h));
+    
+    // Rasterize chart faces, check that all bits are not set.
+    const uint faceCount = chart->faceCount();
+    for (uint f = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = chart->chartMesh()->faceAt(f);
+        
+        Vector2 vertices[4];
+
+        uint edgeCount = 0;
+        for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+        {
+            if (edgeCount < 4)
+            {
+                vertices[edgeCount] = it.vertex()->tex + Vector2(0.5) + Vector2(float(padding), float(padding));
+            }
+            edgeCount++;
+        }
+
+        if (edgeCount == 3)
+        {
+            Raster::drawTriangle(Raster::Mode_Antialiased, extents, true, vertices, AtlasPacker::setBitsCallback, bitmap);
+        }
+        else
+        {
+            Raster::drawQuad(Raster::Mode_Antialiased, extents, true, vertices, AtlasPacker::setBitsCallback, bitmap);
+        }
+    }
+
+    // Expand chart by padding pixels. (dilation)
+    BitMap tmp(w, h);
+    for (int i = 0; i < padding; i++) {
+        tmp.clearAll();
+
+        for (int y = 0; y < h; y++) {
+            for (int x = 0; x < w; x++) {
+                bool b = bitmap->bitAt(x, y);
+                if (!b) {
+                    if (x > 0) {
+                        b |= bitmap->bitAt(x - 1, y);
+                        if (y > 0) b |= bitmap->bitAt(x - 1, y - 1);
+                        if (y < h-1) b |= bitmap->bitAt(x - 1, y + 1);
+                    }
+                    if (y > 0) b |= bitmap->bitAt(x, y - 1);
+                    if (y < h-1) b |= bitmap->bitAt(x, y + 1);
+                    if (x < w-1) {
+                        b |= bitmap->bitAt(x + 1, y);
+                        if (y > 0) b |= bitmap->bitAt(x + 1, y - 1);
+                        if (y < h-1) b |= bitmap->bitAt(x + 1, y + 1);
+                    }
+                }
+                if (b) tmp.setBitAt(x, y);
+            }
+        }
+
+        swap(tmp, *bitmap);
+    }
+}
+
+
+void AtlasPacker::drawChartBitmap(const Chart * chart, BitMap * bitmap, const Vector2 & scale, const Vector2 & offset)
+{
+    const int w = bitmap->width();
+    const int h = bitmap->height();
+    const Vector2 extents = Vector2(float(w), float(h));
+    
+    static const Vector2 pad[4] = {
+        Vector2(-0.5, -0.5),
+        Vector2(0.5, -0.5),
+        Vector2(-0.5, 0.5),
+        Vector2(0.5, 0.5)
+    };
+    /*static const Vector2 pad[4] = {
+        Vector2(-1, -1),
+        Vector2(1, -1),
+        Vector2(-1, 1),
+        Vector2(1, 1)
+    };*/
+
+    // Rasterize 4 times to add proper padding.
+    for (int i = 0; i < 4; i++) {
+
+        // Rasterize chart faces, check that all bits are not set.
+        const uint faceCount = chart->chartMesh()->faceCount();
+        for (uint f = 0; f < faceCount; f++)
+        {
+            const HalfEdge::Face * face = chart->chartMesh()->faceAt(f);
+            
+            Vector2 vertices[4];
+
+            uint edgeCount = 0;
+            for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+            {
+                if (edgeCount < 4)
+                {
+                    vertices[edgeCount] = it.vertex()->tex * scale + offset + pad[i];
+                    nvCheck(ftoi_ceil(vertices[edgeCount].x) >= 0);
+                    nvCheck(ftoi_ceil(vertices[edgeCount].y) >= 0);
+                    nvCheck(ftoi_ceil(vertices[edgeCount].x) <= w);
+                    nvCheck(ftoi_ceil(vertices[edgeCount].y) <= h);
+                }
+                edgeCount++;
+            }
+
+            if (edgeCount == 3)
+            {
+                Raster::drawTriangle(Raster::Mode_Antialiased, extents, /*enableScissors=*/true, vertices, AtlasPacker::setBitsCallback, bitmap);
+            }
+            else
+            {
+                Raster::drawQuad(Raster::Mode_Antialiased, extents, /*enableScissors=*/true, vertices, AtlasPacker::setBitsCallback, bitmap);
+            }
+        }
+    }
+
+    // @@ This only allows us to expand the size in texel intervals.
+    /*if (m_padding_x != 0 && m_padding_y != 0)*/ {
+
+        // Expand chart by padding pixels. (dilation)
+        BitMap tmp(w, h);
+        //for (int i = 0; i < 1; i++) {
+            tmp.clearAll();
+
+            for (int y = 0; y < h; y++) {
+                for (int x = 0; x < w; x++) {
+                    bool b = bitmap->bitAt(x, y);
+                    if (!b) {
+                        if (x > 0) {
+                            b |= bitmap->bitAt(x - 1, y);
+                            if (y > 0) b |= bitmap->bitAt(x - 1, y - 1);
+                            if (y < h-1) b |= bitmap->bitAt(x - 1, y + 1);
+                        }
+                        if (y > 0) b |= bitmap->bitAt(x, y - 1);
+                        if (y < h-1) b |= bitmap->bitAt(x, y + 1);
+                        if (x < w-1) {
+                            b |= bitmap->bitAt(x + 1, y);
+                            if (y > 0) b |= bitmap->bitAt(x + 1, y - 1);
+                            if (y < h-1) b |= bitmap->bitAt(x + 1, y + 1);
+                        }
+                    }
+                    if (b) tmp.setBitAt(x, y);
+                }
+            }
+
+            swap(tmp, *bitmap);
+        //}
+    }
+}
+
+bool AtlasPacker::canAddChart(const BitMap * bitmap, int atlas_w, int atlas_h, int offset_x, int offset_y, int r)
+{
+    nvDebugCheck(r == 0 || r == 1);
+
+    // Check whether the two bitmaps overlap.
+
+    const int w = bitmap->width();
+    const int h = bitmap->height();
+    
+    if (r == 0) {
+        for (int y = 0; y < h; y++) {
+            int yy = y + offset_y;
+            if (yy >= 0) {
+                for (int x = 0; x < w; x++) {
+                    int xx = x + offset_x;
+                    if (xx >= 0) {
+                        if (bitmap->bitAt(x, y)) {
+                            if (xx < atlas_w && yy < atlas_h) {
+                                if (m_bitmap.bitAt(xx, yy)) return false;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+    else if (r == 1) {
+        for (int y = 0; y < h; y++) {
+            int xx = y + offset_x;
+            if (xx >= 0) {
+                for (int x = 0; x < w; x++) {
+                    int yy = x + offset_y;
+                    if (yy >= 0) {
+                        if (bitmap->bitAt(x, y)) {
+                            if (xx < atlas_w && yy < atlas_h) {
+                                if (m_bitmap.bitAt(xx, yy)) return false;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+    
+    return true;
+}
+
+#if 0
+void AtlasPacker::checkCanAddChart(const Chart * chart, int w, int h, int x, int y, int r)
+{
+    nvDebugCheck(r == 0 || r == 1);
+    Vector2 extents = Vector2(float(w), float(h));
+    Vector2 offset = Vector2(float(x), float(y));
+
+    // Rasterize chart faces, set bits.
+    const uint faceCount = chart->faceCount();
+    for (uint f = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = chart->chartMesh()->faceAt(f);
+        
+        Vector2 vertices[4];
+
+        uint edgeCount = 0;
+        for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+        {
+            if (edgeCount < 4)
+            {
+                Vector2 t = it.vertex()->tex;
+                if (r == 1) swap(t.x, t.y);
+                vertices[edgeCount] = t + offset;
+            }
+            edgeCount++;
+        }
+
+        if (edgeCount == 3)
+        {
+            Raster::drawTriangle(Raster::Mode_Antialiased, extents, /*enableScissors=*/true, vertices, AtlasPacker::checkBitsCallback, &m_bitmap);
+        }
+        else
+        {
+            Raster::drawQuad(Raster::Mode_Antialiased, extents, /*enableScissors=*/true, vertices, AtlasPacker::checkBitsCallback, &m_bitmap);
+        }
+    }
+}
+#endif // 0
+
+
+static Color32 chartColor = Color32(0);
+static void selectRandomColor(MTRand & rand) {
+    // Pick random color for this chart. @@ Select random hue, but fixed saturation/luminance?
+    chartColor.r = 128 + rand.getRange(127);
+    chartColor.g = 128 + rand.getRange(127);
+    chartColor.b = 128 + rand.getRange(127);
+    chartColor.a = 255;
+}
+static bool debugDrawCallback(void * param, int x, int y, Vector3::Arg, Vector3::Arg, Vector3::Arg, float area)
+{
+    Image * image = (Image *)param;
+
+    if (area > 0.0) {
+        Color32 c = image->pixel(x, y);
+        c.r = chartColor.r;
+        c.g = chartColor.g;
+        c.b = chartColor.b;
+        c.a += U8(ftoi_round(0.5f * area * 255));
+        image->pixel(x, y) = c;
+    }
+
+    return true;
+}
+
+void AtlasPacker::addChart(const Chart * chart, int w, int h, int x, int y, int r, Image * debugOutput)
+{
+    nvDebugCheck(r == 0 || r == 1);
+
+    nvDebugCheck(debugOutput != NULL);
+    selectRandomColor(m_rand);
+
+    Vector2 extents = Vector2(float(w), float(h));
+    Vector2 offset = Vector2(float(x), float(y)) + Vector2(0.5);
+
+    // Rasterize chart faces, set bits.
+    const uint faceCount = chart->faceCount();
+    for (uint f = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = chart->chartMesh()->faceAt(f);
+        
+        Vector2 vertices[4];
+
+        uint edgeCount = 0;
+        for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+        {
+            if (edgeCount < 4)
+            {
+                Vector2 t = it.vertex()->tex;
+                if (r == 1) swap(t.x, t.y);
+                vertices[edgeCount] = t + offset;
+            }
+            edgeCount++;
+        }
+
+        if (edgeCount == 3)
+        {
+            Raster::drawTriangle(Raster::Mode_Antialiased, extents, /*enableScissors=*/true, vertices, debugDrawCallback, debugOutput);
+        }
+        else
+        {
+            Raster::drawQuad(Raster::Mode_Antialiased, extents, /*enableScissors=*/true, vertices, debugDrawCallback, debugOutput);
+        }
+    }
+}
+
+
+void AtlasPacker::addChart(const BitMap * bitmap, int atlas_w, int atlas_h, int offset_x, int offset_y, int r, Image * debugOutput)
+{
+    nvDebugCheck(r == 0 || r == 1);
+
+    // Check whether the two bitmaps overlap.
+
+    const int w = bitmap->width();
+    const int h = bitmap->height();
+
+    if (debugOutput != NULL) {
+        selectRandomColor(m_rand);
+    }
+
+    if (r == 0) {
+        for (int y = 0; y < h; y++) {
+            int yy = y + offset_y;
+            if (yy >= 0) {
+                for (int x = 0; x < w; x++) {
+                    int xx = x + offset_x;
+                    if (xx >= 0) {
+                        if (bitmap->bitAt(x, y)) {
+                            if (xx < atlas_w && yy < atlas_h) {
+                                if (debugOutput) debugOutput->pixel(xx, yy) = chartColor;
+                                else {
+                                    nvDebugCheck(m_bitmap.bitAt(xx, yy) == false);
+                                    m_bitmap.setBitAt(xx, yy);
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+    else if (r == 1) {
+        for (int y = 0; y < h; y++) {
+            int xx = y + offset_x;
+            if (xx >= 0) {
+                for (int x = 0; x < w; x++) {
+                    int yy = x + offset_y;
+                    if (yy >= 0) {
+                        if (bitmap->bitAt(x, y)) {
+                            if (xx < atlas_w && yy < atlas_h) {
+                                if (debugOutput) debugOutput->pixel(xx, yy) = chartColor;
+                                else {
+                                    nvDebugCheck(m_bitmap.bitAt(xx, yy) == false);
+                                    m_bitmap.setBitAt(xx, yy);
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+
+
+/*static*/ bool AtlasPacker::checkBitsCallback(void * param, int x, int y, Vector3::Arg, Vector3::Arg, Vector3::Arg, float)
+{
+    BitMap * bitmap = (BitMap * )param;
+
+    nvDebugCheck(bitmap->bitAt(x, y) == false);
+
+    return true;
+}
+
+/*static*/ bool AtlasPacker::setBitsCallback(void * param, int x, int y, Vector3::Arg, Vector3::Arg, Vector3::Arg, float area)
+{
+    BitMap * bitmap = (BitMap * )param;
+
+    if (area > 0.0) {
+        bitmap->setBitAt(x, y);
+    }
+
+    return true;
+}
+
+
+
+float AtlasPacker::computeAtlasUtilization() const {
+    const uint w = m_width;
+    const uint h = m_height;
+    nvDebugCheck(w <= m_bitmap.width());
+    nvDebugCheck(h <= m_bitmap.height());
+
+    uint count = 0;
+    for (uint y = 0; y < h; y++) {
+        for (uint x = 0; x < w; x++) {
+            count += m_bitmap.bitAt(x, y);
+        }
+    }
+
+    return float(count) / (w * h);
+}
diff --git a/thirdparty/thekla_atlas/nvmesh/param/AtlasPacker.h b/thirdparty/thekla_atlas/nvmesh/param/AtlasPacker.h
new file mode 100644
index 0000000000..2d305f38cd
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/AtlasPacker.h
@@ -0,0 +1,63 @@
+// This code is in the public domain -- castano@gmail.com
+
+#pragma once
+#ifndef NV_MESH_ATLASPACKER_H
+#define NV_MESH_ATLASPACKER_H
+
+#include "nvcore/RadixSort.h"
+#include "nvmath/Vector.h"
+#include "nvmath/Random.h"
+#include "nvimage/BitMap.h"
+#include "nvimage/Image.h"
+
+#include "nvmesh/nvmesh.h"
+
+
+namespace nv
+{
+    class Atlas;
+    class Chart;
+
+    struct AtlasPacker
+    {
+        AtlasPacker(Atlas * atlas);
+        ~AtlasPacker();
+
+        void packCharts(int quality, float texelArea, bool blockAligned, bool conservative);
+        float computeAtlasUtilization() const;
+
+    private:
+
+        void findChartLocation(int quality, const BitMap * bitmap, Vector2::Arg extents, int w, int h, int * best_x, int * best_y, int * best_w, int * best_h, int * best_r);
+        void findChartLocation_bruteForce(const BitMap * bitmap, Vector2::Arg extents, int w, int h, int * best_x, int * best_y, int * best_w, int * best_h, int * best_r);
+        void findChartLocation_random(const BitMap * bitmap, Vector2::Arg extents, int w, int h, int * best_x, int * best_y, int * best_w, int * best_h, int * best_r, int minTrialCount);
+
+        void drawChartBitmapDilate(const Chart * chart, BitMap * bitmap, int padding);
+        void drawChartBitmap(const Chart * chart, BitMap * bitmap, const Vector2 & scale, const Vector2 & offset);
+        
+        bool canAddChart(const BitMap * bitmap, int w, int h, int x, int y, int r);
+        void addChart(const BitMap * bitmap, int w, int h, int x, int y, int r, Image * debugOutput);
+        //void checkCanAddChart(const Chart * chart, int w, int h, int x, int y, int r);
+        void addChart(const Chart * chart, int w, int h, int x, int y, int r, Image * debugOutput);
+        
+
+        static bool checkBitsCallback(void * param, int x, int y, Vector3::Arg bar, Vector3::Arg dx, Vector3::Arg dy, float coverage);
+        static bool setBitsCallback(void * param, int x, int y, Vector3::Arg bar, Vector3::Arg dx, Vector3::Arg dy, float coverage);
+
+    private:
+
+        Atlas * m_atlas;
+        BitMap m_bitmap;
+        Image m_debug_bitmap;
+        RadixSort m_radix;
+
+        uint m_width;
+        uint m_height;
+        
+        MTRand m_rand;
+       
+    };
+
+} // nv namespace
+
+#endif // NV_MESH_ATLASPACKER_H
diff --git a/thirdparty/thekla_atlas/nvmesh/param/LeastSquaresConformalMap.cpp b/thirdparty/thekla_atlas/nvmesh/param/LeastSquaresConformalMap.cpp
new file mode 100644
index 0000000000..cd1e8bbb7b
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/LeastSquaresConformalMap.cpp
@@ -0,0 +1,483 @@
+// Copyright NVIDIA Corporation 2008 -- Ignacio Castano <icastano@nvidia.com>
+
+#include "nvmesh.h" // pch
+
+#include "LeastSquaresConformalMap.h"
+#include "ParameterizationQuality.h"
+#include "Util.h"
+
+#include "nvmesh/halfedge/Mesh.h"
+#include "nvmesh/halfedge/Vertex.h"
+#include "nvmesh/halfedge/Face.h"
+
+#include "nvmath/Sparse.h"
+#include "nvmath/Solver.h"
+#include "nvmath/Vector.inl"
+
+#include "nvcore/Array.inl"
+
+
+using namespace nv;
+using namespace HalfEdge;
+
+namespace
+{
+
+    // Test all pairs of vertices in the boundary and check distance.
+    static void findDiameterVertices(HalfEdge::Mesh * mesh, HalfEdge::Vertex ** a, HalfEdge::Vertex ** b)
+    {
+        nvDebugCheck(mesh != NULL);
+        nvDebugCheck(a != NULL);
+        nvDebugCheck(b != NULL);
+
+        const uint vertexCount = mesh->vertexCount();
+
+        float maxLength = 0.0f;
+
+        for (uint v0 = 1; v0 < vertexCount; v0++)
+        {
+            HalfEdge::Vertex * vertex0 = mesh->vertexAt(v0);
+            nvDebugCheck(vertex0 != NULL);
+
+            if (!vertex0->isBoundary()) continue;
+
+            for (uint v1 = 0; v1 < v0; v1++)
+            {
+                HalfEdge::Vertex * vertex1 = mesh->vertexAt(v1);
+                nvDebugCheck(vertex1 != NULL);
+
+                if (!vertex1->isBoundary()) continue;
+
+                float len = length(vertex0->pos - vertex1->pos);
+
+                if (len > maxLength)
+                {
+                    maxLength = len;
+
+                    *a = vertex0;
+                    *b = vertex1;
+                }
+            }
+        }
+
+        nvDebugCheck(*a != NULL && *b != NULL);
+    }
+
+    // Fast sweep in 3 directions
+    static bool findApproximateDiameterVertices(HalfEdge::Mesh * mesh, HalfEdge::Vertex ** a, HalfEdge::Vertex ** b)
+    {
+        nvDebugCheck(mesh != NULL);
+        nvDebugCheck(a != NULL);
+        nvDebugCheck(b != NULL);
+
+        const uint vertexCount = mesh->vertexCount();
+
+        HalfEdge::Vertex * minVertex[3];
+        HalfEdge::Vertex * maxVertex[3];
+
+        minVertex[0] = minVertex[1] = minVertex[2] = NULL;
+        maxVertex[0] = maxVertex[1] = maxVertex[2] = NULL;
+
+        for (uint v = 1; v < vertexCount; v++)
+        {
+            HalfEdge::Vertex * vertex = mesh->vertexAt(v);
+            nvDebugCheck(vertex != NULL);
+
+            if (vertex->isBoundary())
+            {
+                minVertex[0] = minVertex[1] = minVertex[2] = vertex;
+                maxVertex[0] = maxVertex[1] = maxVertex[2] = vertex;
+                break;
+            }
+        }
+
+        if (minVertex[0] == NULL)
+        {
+            // Input mesh has not boundaries.
+            return false;
+        }
+
+        for (uint v = 1; v < vertexCount; v++)
+        {
+            HalfEdge::Vertex * vertex = mesh->vertexAt(v);
+            nvDebugCheck(vertex != NULL);
+
+            if (!vertex->isBoundary())
+            {
+                // Skip interior vertices.
+                continue;
+            }
+
+            if (vertex->pos.x < minVertex[0]->pos.x) minVertex[0] = vertex;
+            else if (vertex->pos.x > maxVertex[0]->pos.x) maxVertex[0] = vertex;
+
+            if (vertex->pos.y < minVertex[1]->pos.y) minVertex[1] = vertex;
+            else if (vertex->pos.y > maxVertex[1]->pos.y) maxVertex[1] = vertex;
+
+            if (vertex->pos.z < minVertex[2]->pos.z) minVertex[2] = vertex;
+            else if (vertex->pos.z > maxVertex[2]->pos.z) maxVertex[2] = vertex;
+        }
+
+        float lengths[3];
+        for (int i = 0; i < 3; i++)
+        {
+            lengths[i] = length(minVertex[i]->pos - maxVertex[i]->pos);
+        }
+
+        if (lengths[0] > lengths[1] && lengths[0] > lengths[2])
+        {
+            *a = minVertex[0];
+            *b = maxVertex[0];
+        }
+        else if (lengths[1] > lengths[2])
+        {
+            *a = minVertex[1];
+            *b = maxVertex[1];
+        }
+        else
+        {
+            *a = minVertex[2];
+            *b = maxVertex[2];
+        }
+
+        return true;
+    }
+
+    // Conformal relations from Bruno Levy:
+
+    // Computes the coordinates of the vertices of a triangle
+    // in a local 2D orthonormal basis of the triangle's plane.
+    static void project_triangle(Vector3::Arg p0, Vector3::Arg p1, Vector3::Arg p2, Vector2 * z0, Vector2 * z1, Vector2 * z2)
+    {
+        Vector3 X = normalize(p1 - p0, 0.0f);
+        Vector3 Z = normalize(cross(X, (p2 - p0)), 0.0f);
+        Vector3 Y = normalize(cross(Z, X), 0.0f);
+
+        float x0 = 0.0f;
+        float y0 = 0.0f;
+        float x1 = length(p1 - p0);
+        float y1 = 0.0f;
+        float x2 = dot((p2 - p0), X);
+        float y2 = dot((p2 - p0), Y);
+
+        *z0 = Vector2(x0, y0);
+        *z1 = Vector2(x1, y1);
+        *z2 = Vector2(x2, y2);
+    }
+
+    // LSCM equation, geometric form :
+    // (Z1 - Z0)(U2 - U0) = (Z2 - Z0)(U1 - U0)
+    // Where Uk = uk + i.vk is the complex number 
+    //                       corresponding to (u,v) coords
+    //       Zk = xk + i.yk is the complex number 
+    //                       corresponding to local (x,y) coords
+    // cool: no divide with this expression,
+    //  makes it more numerically stable in
+    //  the presence of degenerate triangles.
+
+    static void setup_conformal_map_relations(SparseMatrix & A, int row, const HalfEdge::Vertex * v0, const HalfEdge::Vertex * v1, const HalfEdge::Vertex * v2)
+    {
+        int id0 = v0->id;
+        int id1 = v1->id;
+        int id2 = v2->id;
+
+        Vector3 p0 = v0->pos;
+        Vector3 p1 = v1->pos;
+        Vector3 p2 = v2->pos;
+
+        Vector2 z0, z1, z2;
+        project_triangle(p0, p1, p2, &z0, &z1, &z2);
+
+        Vector2 z01 = z1 - z0;
+        Vector2 z02 = z2 - z0;
+
+        float a = z01.x;
+        float b = z01.y;
+        float c = z02.x;
+        float d = z02.y;
+        nvCheck(b == 0.0f);
+
+        // Note  : 2*id + 0 --> u
+        //         2*id + 1 --> v
+        int u0_id = 2 * id0 + 0;
+        int v0_id = 2 * id0 + 1;
+        int u1_id = 2 * id1 + 0;
+        int v1_id = 2 * id1 + 1;
+        int u2_id = 2 * id2 + 0;
+        int v2_id = 2 * id2 + 1;
+
+        // Note : b = 0
+
+        // Real part
+        A.setCoefficient(u0_id, 2 * row + 0, -a+c);
+        A.setCoefficient(v0_id, 2 * row + 0,  b-d);
+        A.setCoefficient(u1_id, 2 * row + 0,   -c);
+        A.setCoefficient(v1_id, 2 * row + 0,    d);
+        A.setCoefficient(u2_id, 2 * row + 0,    a);
+
+        // Imaginary part
+        A.setCoefficient(u0_id, 2 * row + 1, -b+d);
+        A.setCoefficient(v0_id, 2 * row + 1, -a+c);
+        A.setCoefficient(u1_id, 2 * row + 1,   -d);
+        A.setCoefficient(v1_id, 2 * row + 1,   -c);
+        A.setCoefficient(v2_id, 2 * row + 1,    a);
+    }
+
+
+    // Conformal relations from Brecht Van Lommel (based on ABF):
+
+    static float vec_angle_cos(Vector3::Arg v1, Vector3::Arg v2, Vector3::Arg v3)
+    {
+        Vector3 d1 = v1 - v2;
+        Vector3 d2 = v3 - v2;
+        return clamp(dot(d1, d2) / (length(d1) * length(d2)), -1.0f, 1.0f);
+    }
+
+    static float vec_angle(Vector3::Arg v1, Vector3::Arg v2, Vector3::Arg v3)
+    {
+        float dot = vec_angle_cos(v1, v2, v3);
+        return acosf(dot);
+    }
+
+    static void triangle_angles(Vector3::Arg v1, Vector3::Arg v2, Vector3::Arg v3, float *a1, float *a2, float *a3)
+    {
+        *a1 = vec_angle(v3, v1, v2);
+        *a2 = vec_angle(v1, v2, v3);
+        *a3 = PI - *a2 - *a1;
+    }
+
+    static void triangle_cosines(Vector3::Arg v1, Vector3::Arg v2, Vector3::Arg v3, float *a1, float *a2, float *a3)
+    {
+        *a1 = vec_angle_cos(v3, v1, v2);
+        *a2 = vec_angle_cos(v1, v2, v3);
+        *a3 = vec_angle_cos(v2, v3, v1);
+    }
+
+    static void setup_abf_relations(SparseMatrix & A, int row, const HalfEdge::Vertex * v0, const HalfEdge::Vertex * v1, const HalfEdge::Vertex * v2)
+    {
+        int id0 = v0->id;
+        int id1 = v1->id;
+        int id2 = v2->id;
+
+        Vector3 p0 = v0->pos;
+        Vector3 p1 = v1->pos;
+        Vector3 p2 = v2->pos;
+
+#if 1
+        // @@ IC: Wouldn't it be more accurate to return cos and compute 1-cos^2?
+        // It does indeed seem to be a little bit more robust.
+        // @@ Need to revisit this more carefully!
+
+        float a0, a1, a2;
+        triangle_angles(p0, p1, p2, &a0, &a1, &a2);
+
+        float s0 = sinf(a0);
+        float s1 = sinf(a1);
+        float s2 = sinf(a2);
+
+        /*// Hack for degenerate triangles.
+        if (equal(s0, 0) && equal(s1, 0) && equal(s2, 0)) {
+            if (equal(a0, 0)) a0 += 0.001f;
+            if (equal(a1, 0)) a1 += 0.001f;
+            if (equal(a2, 0)) a2 += 0.001f;
+
+            if (equal(a0, PI)) a0 = PI - a1 - a2;
+            if (equal(a1, PI)) a1 = PI - a0 - a2;
+            if (equal(a2, PI)) a2 = PI - a0 - a1;
+
+            s0 = sinf(a0);
+            s1 = sinf(a1);
+            s2 = sinf(a2);
+        }*/
+
+        if (s1 > s0 && s1 > s2)
+        {
+            swap(s1, s2);
+            swap(s0, s1);
+
+            swap(a1, a2);
+            swap(a0, a1);
+
+            swap(id1, id2);
+            swap(id0, id1);
+        }
+        else if (s0 > s1 && s0 > s2)
+        {
+            swap(s0, s2);
+            swap(s0, s1);
+
+            swap(a0, a2);
+            swap(a0, a1);
+
+            swap(id0, id2);
+            swap(id0, id1);
+        }
+
+        float c0 = cosf(a0);
+#else
+        float c0, c1, c2;
+        triangle_cosines(p0, p1, p2, &c0, &c1, &c2);
+
+        float s0 = 1 - c0*c0;
+        float s1 = 1 - c1*c1;
+        float s2 = 1 - c2*c2;
+
+        nvDebugCheck(s0 != 0 || s1 != 0 || s2 != 0);
+
+        if (s1 > s0 && s1 > s2)
+        {
+            swap(s1, s2);
+            swap(s0, s1);
+
+            swap(c1, c2);
+            swap(c0, c1);
+
+            swap(id1, id2);
+            swap(id0, id1);
+        }
+        else if (s0 > s1 && s0 > s2)
+        {
+            swap(s0, s2);
+            swap(s0, s1);
+
+            swap(c0, c2);
+            swap(c0, c1);
+
+            swap(id0, id2);
+            swap(id0, id1);
+        }
+#endif
+
+        float ratio = (s2 == 0.0f) ? 1.0f: s1/s2;
+        float cosine = c0 * ratio;
+        float sine = s0 * ratio;
+
+        // Note  : 2*id + 0 --> u
+        //         2*id + 1 --> v
+        int u0_id = 2 * id0 + 0;
+        int v0_id = 2 * id0 + 1;
+        int u1_id = 2 * id1 + 0;
+        int v1_id = 2 * id1 + 1;
+        int u2_id = 2 * id2 + 0;
+        int v2_id = 2 * id2 + 1;
+
+        // Real part
+        A.setCoefficient(u0_id, 2 * row + 0, cosine - 1.0f);
+        A.setCoefficient(v0_id, 2 * row + 0, -sine);
+        A.setCoefficient(u1_id, 2 * row + 0, -cosine);
+        A.setCoefficient(v1_id, 2 * row + 0, sine);
+        A.setCoefficient(u2_id, 2 * row + 0, 1);
+
+        // Imaginary part
+        A.setCoefficient(u0_id, 2 * row + 1, sine);
+        A.setCoefficient(v0_id, 2 * row + 1, cosine - 1.0f);
+        A.setCoefficient(u1_id, 2 * row + 1, -sine);
+        A.setCoefficient(v1_id, 2 * row + 1, -cosine);
+        A.setCoefficient(v2_id, 2 * row + 1, 1);
+    }
+
+} // namespace
+
+
+bool nv::computeLeastSquaresConformalMap(HalfEdge::Mesh * mesh)
+{
+    nvDebugCheck(mesh != NULL);
+
+    // For this to work properly, mesh should not have colocals that have the same 
+    // attributes, unless you want the vertices to actually have different texcoords.
+
+    const uint vertexCount = mesh->vertexCount();
+    const uint D = 2 * vertexCount;
+    const uint N = 2 * countMeshTriangles(mesh);
+
+    // N is the number of equations (one per triangle)
+    // D is the number of variables (one per vertex; there are 2 pinned vertices).
+	if (N < D - 4) {
+		return false;
+	}
+
+    SparseMatrix A(D, N);
+    FullVector b(N);
+    FullVector x(D);
+
+    // Fill b:
+    b.fill(0.0f);
+
+    // Fill x:
+    HalfEdge::Vertex * v0;
+    HalfEdge::Vertex * v1;
+    if (!findApproximateDiameterVertices(mesh, &v0, &v1))
+    {
+        // Mesh has no boundaries.
+        return false;
+    }
+    if (v0->tex == v1->tex)
+    {
+        // LSCM expects an existing parameterization.
+        return false;
+    }
+
+    for (uint v = 0; v < vertexCount; v++)
+    {
+        HalfEdge::Vertex * vertex = mesh->vertexAt(v);
+        nvDebugCheck(vertex != NULL);
+
+        // Initial solution.
+        x[2 * v + 0] = vertex->tex.x;
+        x[2 * v + 1] = vertex->tex.y;
+    }
+
+    // Fill A:
+    const uint faceCount = mesh->faceCount();
+    for (uint f = 0, t = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = mesh->faceAt(f);
+        nvDebugCheck(face != NULL);
+        nvDebugCheck(face->edgeCount() == 3);
+
+        const HalfEdge::Vertex * vertex0 = NULL;
+
+        for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+        {
+            const HalfEdge::Edge * edge = it.current();
+            nvCheck(edge != NULL);
+
+            if (vertex0 == NULL)
+            {
+                vertex0 = edge->vertex;
+            }
+            else if (edge->next->vertex != vertex0)
+            {
+                const HalfEdge::Vertex * vertex1 = edge->from();
+                const HalfEdge::Vertex * vertex2 = edge->to();
+
+                setup_abf_relations(A, t, vertex0, vertex1, vertex2);
+                //setup_conformal_map_relations(A, t, vertex0, vertex1, vertex2);
+
+                t++;
+            }
+        }
+    }
+
+    const uint lockedParameters[] =
+    {
+        2 * v0->id + 0,
+        2 * v0->id + 1,
+        2 * v1->id + 0,
+        2 * v1->id + 1
+    };
+
+    // Solve
+    LeastSquaresSolver(A, b, x, lockedParameters, 4, 0.000001f);
+
+    // Map x back to texcoords:
+    for (uint v = 0; v < vertexCount; v++)
+    {
+        HalfEdge::Vertex * vertex = mesh->vertexAt(v);
+        nvDebugCheck(vertex != NULL);
+
+        vertex->tex = Vector2(x[2 * v + 0], x[2 * v + 1]);
+    }
+
+    return true;
+}
diff --git a/thirdparty/thekla_atlas/nvmesh/param/LeastSquaresConformalMap.h b/thirdparty/thekla_atlas/nvmesh/param/LeastSquaresConformalMap.h
new file mode 100644
index 0000000000..51fbf193c8
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/LeastSquaresConformalMap.h
@@ -0,0 +1,15 @@
+// Copyright NVIDIA Corporation 2008 -- Ignacio Castano <icastano@nvidia.com>
+
+#pragma once
+#ifndef NV_MESH_LEASTSQUARESCONFORMALMAP_H
+#define NV_MESH_LEASTSQUARESCONFORMALMAP_H
+
+namespace nv
+{
+    namespace HalfEdge { class Mesh; }
+
+    bool computeLeastSquaresConformalMap(HalfEdge::Mesh * mesh);
+
+} // nv namespace
+
+#endif // NV_MESH_LEASTSQUARESCONFORMALMAP_H
diff --git a/thirdparty/thekla_atlas/nvmesh/param/OrthogonalProjectionMap.cpp b/thirdparty/thekla_atlas/nvmesh/param/OrthogonalProjectionMap.cpp
new file mode 100644
index 0000000000..d6e5e30561
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/OrthogonalProjectionMap.cpp
@@ -0,0 +1,99 @@
+// This code is in the public domain -- castano@gmail.com
+
+#include "nvmesh.h" // pch
+
+#include "OrthogonalProjectionMap.h"
+
+#include "nvcore/Array.inl"
+
+#include "nvmath/Fitting.h"
+#include "nvmath/Vector.inl"
+#include "nvmath/Box.inl"
+#include "nvmath/Plane.inl"
+
+#include "nvmesh/halfedge/Mesh.h"
+#include "nvmesh/halfedge/Vertex.h"
+#include "nvmesh/halfedge/Face.h"
+#include "nvmesh/geometry/Bounds.h"
+
+
+using namespace nv;
+
+bool nv::computeOrthogonalProjectionMap(HalfEdge::Mesh * mesh)
+{
+    Vector3 axis[2];
+
+#if 1
+
+    uint vertexCount = mesh->vertexCount();
+    Array<Vector3> points(vertexCount);
+    points.resize(vertexCount);
+
+    for (uint i = 0; i < vertexCount; i++)
+    {
+        points[i] = mesh->vertexAt(i)->pos;
+    }
+
+#if 0
+    axis[0] = Fit::computePrincipalComponent_EigenSolver(vertexCount, points.buffer());
+    axis[0] = normalize(axis[0]);
+
+    Plane plane = Fit::bestPlane(vertexCount, points.buffer());
+
+    Vector3 n = plane.vector();
+
+    axis[1] = cross(axis[0], n);
+    axis[1] = normalize(axis[1]);
+#else
+    // Avoid redundant computations.
+    float matrix[6];
+    Fit::computeCovariance(vertexCount, points.buffer(), matrix);
+
+    if (matrix[0] == 0 && matrix[3] == 0 && matrix[5] == 0) {
+        return false;
+    }
+
+    float eigenValues[3];
+    Vector3 eigenVectors[3];
+    if (!nv::Fit::eigenSolveSymmetric3(matrix, eigenValues, eigenVectors)) {
+        return false;
+    }
+
+    axis[0] = normalize(eigenVectors[0]);
+    axis[1] = normalize(eigenVectors[1]);
+#endif
+
+
+#else
+
+    // IC: I thought this was generally more robust, but turns out it's not even guaranteed to return a valid projection. Imagine a narrow quad perpendicular to one plane, but rotated so that the shortest axis of 
+    // the bounding box is in the direction of that plane.
+
+    // Use the shortest box axis
+    Box box = MeshBounds::box(mesh);
+    Vector3 dir = box.extents();
+
+    if (fabs(dir.x) <= fabs(dir.y) && fabs(dir.x) <= fabs(dir.z)) {
+        axis[0] = Vector3(0, 1, 0); 
+        axis[1] = Vector3(0, 0, 1);
+    }
+    else if (fabs(dir.y) <= fabs(dir.z)) {
+        axis[0] = Vector3(1, 0, 0); 
+        axis[1] = Vector3(0, 0, 1);
+    }
+    else {
+        axis[0] = Vector3(1, 0, 0); 
+        axis[1] = Vector3(0, 1, 0);
+    }
+#endif
+
+    // Project vertices to plane.
+    for (HalfEdge::Mesh::VertexIterator it(mesh->vertices()); !it.isDone(); it.advance())
+    {
+        HalfEdge::Vertex * vertex = it.current();
+        vertex->tex.x = dot(axis[0], vertex->pos);
+        vertex->tex.y = dot(axis[1], vertex->pos);
+    }
+
+    return true;
+}
diff --git a/thirdparty/thekla_atlas/nvmesh/param/OrthogonalProjectionMap.h b/thirdparty/thekla_atlas/nvmesh/param/OrthogonalProjectionMap.h
new file mode 100644
index 0000000000..54920413d5
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/OrthogonalProjectionMap.h
@@ -0,0 +1,15 @@
+// This code is in the public domain -- castano@gmail.com
+
+#pragma once
+#ifndef NV_MESH_ORTHOGONALPROJECTIONMAP_H
+#define NV_MESH_ORTHOGONALPROJECTIONMAP_H
+
+namespace nv
+{
+    namespace HalfEdge { class Mesh; }
+
+    bool computeOrthogonalProjectionMap(HalfEdge::Mesh * mesh);
+
+} // nv namespace
+
+#endif // NV_MESH_ORTHOGONALPROJECTIONMAP_H
diff --git a/thirdparty/thekla_atlas/nvmesh/param/ParameterizationQuality.cpp b/thirdparty/thekla_atlas/nvmesh/param/ParameterizationQuality.cpp
new file mode 100644
index 0000000000..683ee603cd
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/ParameterizationQuality.cpp
@@ -0,0 +1,323 @@
+// Copyright NVIDIA Corporation 2008 -- Ignacio Castano <icastano@nvidia.com>
+
+#include "nvmesh.h" // pch
+
+#include "ParameterizationQuality.h"
+
+#include "nvmesh/halfedge/Mesh.h"
+#include "nvmesh/halfedge/Face.h"
+#include "nvmesh/halfedge/Vertex.h"
+#include "nvmesh/halfedge/Edge.h"
+
+#include "nvmath/Vector.inl"
+
+#include "nvcore/Debug.h"
+
+#include <float.h>
+
+
+using namespace nv;
+
+#if 0
+/*
+float triangleConformalEnergy(Vector3 q[3], Vector2 p[3])
+{
+const Vector3 v1 = q[0];
+const Vector3 v2 = q[1];
+const Vector3 v3 = q[2];
+
+const Vector2 w1 = p[0];
+const Vector2 w2 = p[1];
+const Vector2 w3 = p[2];
+
+float x1 = v2.x() - v1.x();
+float x2 = v3.x() - v1.x();
+float y1 = v2.y() - v1.y();
+float y2 = v3.y() - v1.y();
+float z1 = v2.z() - v1.z();
+float z2 = v3.z() - v1.z();
+
+float s1 = w2.x() - w1.x();
+float s2 = w3.x() - w1.x();
+float t1 = w2.y() - w1.y();
+float t2 = w3.y() - w1.y();
+
+float r = 1.0f / (s1 * t2 - s2 * t1);
+Vector3 sdir((t2 * x1 - t1 * x2) * r, (t2 * y1 - t1 * y2) * r, (t2 * z1 - t1 * z2) * r);
+Vector3 tdir((s1 * x2 - s2 * x1) * r, (s1 * y2 - s2 * y1) * r, (s1 * z2 - s2 * z1) * r);
+
+Vector3 N = cross(v3-v1, v2-v1);
+
+// Rotate 90 around N.
+}
+*/
+
+static float triangleConformalEnergy(Vector3 q[3], Vector2 p[3])
+{
+    // Using Denis formulas:
+    Vector3 c0 = q[1] - q[2];
+    Vector3 c1 = q[2] - q[0];
+    Vector3 c2 = q[0] - q[1];
+
+    Vector3 N = cross(-c0, c1);
+    float T = length(N);	// 2T
+    N = normalize(N, 0);
+
+    float cot_alpha0 = dot(-c1, c2) / length(cross(-c1, c2));
+    float cot_alpha1 = dot(-c2, c0) / length(cross(-c2, c0));
+    float cot_alpha2 = dot(-c0, c1) / length(cross(-c0, c1));
+
+    Vector3 t0 = -cot_alpha1 * c1 + cot_alpha2 * c2;
+    Vector3 t1 = -cot_alpha2 * c2 + cot_alpha0 * c0;
+    Vector3 t2 = -cot_alpha0 * c0 + cot_alpha1 * c1;
+
+    nvCheck(equal(length(t0), length(c0)));
+    nvCheck(equal(length(t1), length(c1)));
+    nvCheck(equal(length(t2), length(c2)));
+    nvCheck(equal(dot(t0, c0), 0));
+    nvCheck(equal(dot(t1, c1), 0));
+    nvCheck(equal(dot(t2, c2), 0));
+
+    // Gradients
+    Vector3 grad_u = 1.0f / T * (p[0].x * t0 + p[1].x * t1 + p[2].x * t2);
+    Vector3 grad_v = 1.0f / T * (p[0].y * t0 + p[1].y * t1 + p[2].y * t2);
+
+    // Rotated gradients
+    Vector3 Jgrad_u = 1.0f / T * (p[0].x * c0 + p[1].x * c1 + p[2].x * c2);
+    Vector3 Jgrad_v = 1.0f / T * (p[0].y * c0 + p[1].y * c1 + p[2].y * c2);
+
+    // Using Lengyel's formulas:
+    { 
+        const Vector3 v1 = q[0];
+        const Vector3 v2 = q[1];
+        const Vector3 v3 = q[2];
+
+        const Vector2 w1 = p[0];
+        const Vector2 w2 = p[1];
+        const Vector2 w3 = p[2];
+
+        float x1 = v2.x - v1.x;
+        float x2 = v3.x - v1.x;
+        float y1 = v2.y - v1.y;
+        float y2 = v3.y - v1.y;
+        float z1 = v2.z - v1.z;
+        float z2 = v3.z - v1.z;
+
+        float s1 = w2.x - w1.x;
+        float s2 = w3.x - w1.x;
+        float t1 = w2.y - w1.y;
+        float t2 = w3.y - w1.y;
+
+        float r = 1.0f / (s1 * t2 - s2 * t1);
+        Vector3 sdir((t2 * x1 - t1 * x2) * r, (t2 * y1 - t1 * y2) * r, (t2 * z1 - t1 * z2) * r);
+        Vector3 tdir((s1 * x2 - s2 * x1) * r, (s1 * y2 - s2 * y1) * r, (s1 * z2 - s2 * z1) * r);
+
+        Vector3 Jsdir = cross(N, sdir);
+        Vector3 Jtdir = cross(N, tdir);
+
+        float x = 3;
+    }
+
+    // check: sdir == grad_u
+    // check: tdir == grad_v
+
+    return length(grad_u - Jgrad_v);
+}
+#endif // 0
+
+
+ParameterizationQuality::ParameterizationQuality()
+{
+    m_totalTriangleCount = 0;
+    m_flippedTriangleCount = 0;
+    m_zeroAreaTriangleCount = 0;
+
+    m_parametricArea = 0.0f;
+    m_geometricArea = 0.0f;
+
+    m_stretchMetric = 0.0f;
+    m_maxStretchMetric = 0.0f;
+
+    m_conformalMetric = 0.0f;
+    m_authalicMetric = 0.0f;
+}
+
+ParameterizationQuality::ParameterizationQuality(const HalfEdge::Mesh * mesh)
+{
+    nvDebugCheck(mesh != NULL);
+
+    m_totalTriangleCount = 0;
+    m_flippedTriangleCount = 0;
+    m_zeroAreaTriangleCount = 0;
+
+    m_parametricArea = 0.0f;
+    m_geometricArea = 0.0f;
+
+    m_stretchMetric = 0.0f;
+    m_maxStretchMetric = 0.0f;
+
+    m_conformalMetric = 0.0f;
+    m_authalicMetric = 0.0f;
+
+    const uint faceCount = mesh->faceCount();
+    for (uint f = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = mesh->faceAt(f);
+        const HalfEdge::Vertex * vertex0 = NULL;
+
+        Vector3 p[3];
+        Vector2 t[3];
+
+        for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+        {
+            const HalfEdge::Edge * edge = it.current();
+
+            if (vertex0 == NULL)
+            {
+                vertex0 = edge->vertex;
+
+                p[0] = vertex0->pos;
+                t[0] = vertex0->tex;
+            }
+            else if (edge->to() != vertex0)
+            {
+                p[1] = edge->from()->pos;
+                p[2] = edge->to()->pos;
+                t[1] = edge->from()->tex;
+                t[2] = edge->to()->tex;
+
+                processTriangle(p, t);
+            }
+        }
+    }
+
+    if (m_flippedTriangleCount + m_zeroAreaTriangleCount == faceCount)
+    {
+        // If all triangles are flipped, then none is.
+        m_flippedTriangleCount = 0;
+    }
+
+    nvDebugCheck(isFinite(m_parametricArea) && m_parametricArea >= 0);
+    nvDebugCheck(isFinite(m_geometricArea) && m_geometricArea >= 0);
+    nvDebugCheck(isFinite(m_stretchMetric));
+    nvDebugCheck(isFinite(m_maxStretchMetric));
+    nvDebugCheck(isFinite(m_conformalMetric));
+    nvDebugCheck(isFinite(m_authalicMetric));
+}
+
+bool ParameterizationQuality::isValid() const
+{
+    return m_flippedTriangleCount == 0; // @@ Does not test for self-overlaps.
+}
+
+float ParameterizationQuality::rmsStretchMetric() const
+{
+    if (m_geometricArea == 0) return 0.0f;
+    float normFactor = sqrtf(m_parametricArea / m_geometricArea);
+    return sqrtf(m_stretchMetric / m_geometricArea) * normFactor;
+}
+
+float ParameterizationQuality::maxStretchMetric() const
+{
+    if (m_geometricArea == 0) return 0.0f;
+    float normFactor = sqrtf(m_parametricArea / m_geometricArea);
+    return m_maxStretchMetric * normFactor;
+}
+
+float ParameterizationQuality::rmsConformalMetric() const
+{
+    if (m_geometricArea == 0) return 0.0f;
+    return sqrtf(m_conformalMetric / m_geometricArea);
+}
+
+float ParameterizationQuality::maxAuthalicMetric() const
+{
+    if (m_geometricArea == 0) return 0.0f;
+    return sqrtf(m_authalicMetric / m_geometricArea);
+}
+
+void ParameterizationQuality::operator += (const ParameterizationQuality & pq)
+{
+    m_totalTriangleCount += pq.m_totalTriangleCount;
+    m_flippedTriangleCount += pq.m_flippedTriangleCount;
+    m_zeroAreaTriangleCount += pq.m_zeroAreaTriangleCount;
+
+    m_parametricArea += pq.m_parametricArea;
+    m_geometricArea += pq.m_geometricArea;
+
+    m_stretchMetric += pq.m_stretchMetric;
+    m_maxStretchMetric = max(m_maxStretchMetric, pq.m_maxStretchMetric);
+
+    m_conformalMetric += pq.m_conformalMetric;
+    m_authalicMetric += pq.m_authalicMetric;
+}
+
+
+void ParameterizationQuality::processTriangle(Vector3 q[3], Vector2 p[3])
+{
+    m_totalTriangleCount++;
+
+    // Evaluate texture stretch metric. See:
+    // - "Texture Mapping Progressive Meshes", Sander, Snyder, Gortler & Hoppe
+    // - "Mesh Parameterization: Theory and Practice", Siggraph'07 Course Notes, Hormann, Levy & Sheffer.
+
+    float t1 = p[0].x;
+    float s1 = p[0].y;
+    float t2 = p[1].x;
+    float s2 = p[1].y;
+    float t3 = p[2].x;
+    float s3 = p[2].y;
+
+    float geometricArea = length(cross(q[1] - q[0], q[2] - q[0])) / 2;
+    float parametricArea = ((s2 - s1)*(t3 - t1) - (s3 - s1)*(t2 - t1)) / 2;
+    
+    if (isZero(parametricArea))
+    {
+        m_zeroAreaTriangleCount++;
+        return;
+    }
+
+    Vector3 Ss = (q[0] * (t2- t3) + q[1] * (t3 - t1) + q[2] * (t1 - t2)) / (2 * parametricArea);
+    Vector3 St = (q[0] * (s3- s2) + q[1] * (s1 - s3) + q[2] * (s2 - s1)) / (2 * parametricArea);
+
+    float a = dot(Ss, Ss); // E
+    float b = dot(Ss, St); // F
+    float c = dot(St, St); // G
+
+    // Compute eigen-values of the first fundamental form:
+    float sigma1 = sqrtf(0.5f * max(0.0f, a + c - sqrtf(square(a - c) + 4 * square(b)))); // gamma uppercase, min eigenvalue.
+    float sigma2 = sqrtf(0.5f * max(0.0f, a + c + sqrtf(square(a - c) + 4 * square(b)))); // gamma lowercase, max eigenvalue.
+    nvCheck(sigma2 >= sigma1);
+
+    // isometric: sigma1 = sigma2 = 1
+    // conformal: sigma1 / sigma2 = 1
+    // authalic: sigma1 * sigma2 = 1
+
+    float rmsStretch = sqrtf((a + c) * 0.5f);
+    float rmsStretch2 = sqrtf((square(sigma1) + square(sigma2)) * 0.5f);
+    nvDebugCheck(equal(rmsStretch, rmsStretch2, 0.01f));
+
+    if (parametricArea < 0.0f)
+    {
+        // Count flipped triangles.
+        m_flippedTriangleCount++;
+
+        parametricArea = fabsf(parametricArea);
+    }
+
+    m_stretchMetric += square(rmsStretch) * geometricArea;
+    m_maxStretchMetric = max(m_maxStretchMetric, sigma2);
+
+    if (!isZero(sigma1, 0.000001f)) {
+        // sigma1 is zero when geometricArea is zero.
+        m_conformalMetric += (sigma2 / sigma1) * geometricArea;
+    }
+    m_authalicMetric += (sigma1 * sigma2) * geometricArea;
+
+    // Accumulate total areas.
+    m_geometricArea += geometricArea;
+    m_parametricArea += parametricArea;
+
+
+    //triangleConformalEnergy(q, p);
+}
diff --git a/thirdparty/thekla_atlas/nvmesh/param/ParameterizationQuality.h b/thirdparty/thekla_atlas/nvmesh/param/ParameterizationQuality.h
new file mode 100644
index 0000000000..342e26b889
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/ParameterizationQuality.h
@@ -0,0 +1,56 @@
+// Copyright NVIDIA Corporation 2008 -- Ignacio Castano <icastano@nvidia.com>
+
+#pragma once
+#ifndef NV_MESH_PARAMETERIZATIONQUALITY_H
+#define NV_MESH_PARAMETERIZATIONQUALITY_H
+
+#include <nvmesh/nvmesh.h>
+
+namespace nv
+{
+    class Vector2;
+    class Vector3;
+
+    namespace HalfEdge { class Mesh; }
+
+    // Estimate quality of existing parameterization.
+    NVMESH_CLASS class ParameterizationQuality
+    {
+    public:
+        ParameterizationQuality();
+        ParameterizationQuality(const HalfEdge::Mesh * mesh);
+
+        bool isValid() const;
+
+        float rmsStretchMetric() const;
+        float maxStretchMetric() const;
+
+        float rmsConformalMetric() const;
+        float maxAuthalicMetric() const;
+
+        void operator += (const ParameterizationQuality & pq);
+
+    private:
+
+        void processTriangle(Vector3 p[3], Vector2 t[3]);
+
+    private:
+
+        uint m_totalTriangleCount;
+        uint m_flippedTriangleCount;
+        uint m_zeroAreaTriangleCount;
+
+        float m_parametricArea;
+        float m_geometricArea;
+
+        float m_stretchMetric;
+        float m_maxStretchMetric;
+
+        float m_conformalMetric;
+        float m_authalicMetric;
+
+    };
+
+} // nv namespace
+
+#endif // NV_MESH_PARAMETERIZATIONQUALITY_H
diff --git a/thirdparty/thekla_atlas/nvmesh/param/SingleFaceMap.cpp b/thirdparty/thekla_atlas/nvmesh/param/SingleFaceMap.cpp
new file mode 100644
index 0000000000..4b205de8bf
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/SingleFaceMap.cpp
@@ -0,0 +1,53 @@
+// Copyright NVIDIA Corporation 2008 -- Ignacio Castano <icastano@nvidia.com>
+
+#include "nvmesh.h" // pch
+
+#include "SingleFaceMap.h"
+
+#include "nvmesh/halfedge/Mesh.h"
+#include "nvmesh/halfedge/Vertex.h"
+#include "nvmesh/halfedge/Face.h"
+
+#include "nvmath/Vector.inl"
+
+using namespace nv;
+
+
+
+void nv::computeSingleFaceMap(HalfEdge::Mesh * mesh)
+{
+    nvDebugCheck(mesh != NULL);
+    nvDebugCheck(mesh->faceCount() == 1);
+
+    HalfEdge::Face * face = mesh->faceAt(0);
+    nvCheck(face != NULL);
+
+    Vector3 p0 = face->edge->from()->pos;
+    Vector3 p1 = face->edge->to()->pos;
+
+    Vector3 X = normalizeSafe(p1 - p0, Vector3(0.0f), 0.0f);
+    Vector3 Z = face->normal();
+    Vector3 Y = normalizeSafe(cross(Z, X), Vector3(0.0f), 0.0f);
+
+    uint i = 0;
+    for (HalfEdge::Face::EdgeIterator it(face->edges()); !it.isDone(); it.advance(), i++)
+    {
+        HalfEdge::Vertex * vertex = it.vertex();
+        nvCheck(vertex != NULL);
+
+        if (i == 0)
+        {
+            vertex->tex = Vector2(0);
+        }
+        else
+        {
+            Vector3 pn = vertex->pos;
+
+            float xn = dot((pn - p0), X);
+            float yn = dot((pn - p0), Y);
+
+            vertex->tex = Vector2(xn, yn);
+        }
+    }
+}
+
diff --git a/thirdparty/thekla_atlas/nvmesh/param/SingleFaceMap.h b/thirdparty/thekla_atlas/nvmesh/param/SingleFaceMap.h
new file mode 100644
index 0000000000..b70719f5d8
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/SingleFaceMap.h
@@ -0,0 +1,18 @@
+// Copyright NVIDIA Corporation 2008 -- Ignacio Castano <icastano@nvidia.com>
+
+#pragma once
+#ifndef NV_MESH_SINGLEFACEMAP_H
+#define NV_MESH_SINGLEFACEMAP_H
+
+namespace nv
+{
+    namespace HalfEdge
+    {
+        class Mesh;
+    }
+
+    void computeSingleFaceMap(HalfEdge::Mesh * mesh);
+
+} // nv namespace
+
+#endif // NV_MESH_SINGLEFACEMAP_H
diff --git a/thirdparty/thekla_atlas/nvmesh/param/Util.cpp b/thirdparty/thekla_atlas/nvmesh/param/Util.cpp
new file mode 100644
index 0000000000..fe7b58edf8
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/Util.cpp
@@ -0,0 +1,326 @@
+// This code is in the public domain -- castano@gmail.com
+
+#include "nvmesh.h" // pch
+
+#include "Util.h"
+
+#include "nvmesh/halfedge/Mesh.h"
+#include "nvmesh/halfedge/Face.h"
+#include "nvmesh/halfedge/Vertex.h"
+
+#include "nvmath/Vector.inl"
+
+#include "nvcore/Array.inl"
+
+
+using namespace nv;
+
+// Determine if the given mesh is a	quad mesh.
+bool nv::isQuadMesh(const HalfEdge::Mesh * mesh)
+{
+    nvDebugCheck(mesh != NULL);
+
+    const uint faceCount = mesh->faceCount();
+    for(uint i = 0; i < faceCount; i++) {
+        const HalfEdge::Face * face = mesh->faceAt(i);
+        if (face->edgeCount() != 4) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+bool nv::isTriangularMesh(const HalfEdge::Mesh * mesh)
+{
+    for (HalfEdge::Mesh::ConstFaceIterator it(mesh->faces()); !it.isDone(); it.advance())
+    {
+        const HalfEdge::Face * face = it.current();
+        if (face->edgeCount() != 3) return false;
+    }
+    return true;
+}
+
+
+uint nv::countMeshTriangles(const HalfEdge::Mesh * mesh)
+{
+    const uint faceCount = mesh->faceCount();
+
+    uint triangleCount = 0;
+
+    for (uint f = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = mesh->faceAt(f);
+        
+        uint edgeCount = face->edgeCount();
+        nvDebugCheck(edgeCount > 2);
+
+        triangleCount += edgeCount - 2;
+    }
+
+    return triangleCount;
+}
+
+const HalfEdge::Vertex * nv::findBoundaryVertex(const HalfEdge::Mesh * mesh)
+{
+    const uint vertexCount = mesh->vertexCount();
+
+    for (uint v = 0; v < vertexCount; v++)
+    {
+        const HalfEdge::Vertex * vertex = mesh->vertexAt(v);
+        if (vertex->isBoundary()) return vertex;
+    }
+
+    return NULL;
+}
+
+
+HalfEdge::Mesh * nv::unifyVertices(const HalfEdge::Mesh * inputMesh)
+{
+    HalfEdge::Mesh * mesh = new HalfEdge::Mesh;
+    
+    // Only add the first colocal.
+    const uint vertexCount = inputMesh->vertexCount();
+    for (uint v = 0; v < vertexCount; v++) {
+        const HalfEdge::Vertex * vertex = inputMesh->vertexAt(v);
+        
+        if (vertex->isFirstColocal()) {
+            mesh->addVertex(vertex->pos);
+        }
+    }
+
+    nv::Array<uint> indexArray;
+
+    // Add new faces pointing to first colocals.
+    uint faceCount = inputMesh->faceCount();
+    for (uint f = 0; f < faceCount; f++) {
+        const HalfEdge::Face * face = inputMesh->faceAt(f);
+
+        indexArray.clear();
+
+        for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance()) {
+            const HalfEdge::Edge * edge = it.current();
+            const HalfEdge::Vertex * vertex = edge->vertex->firstColocal();
+
+            indexArray.append(vertex->id);
+        }
+
+        mesh->addFace(indexArray);
+    }
+
+    mesh->linkBoundary();
+
+    return mesh;
+}
+
+#include "nvmath/Basis.h"
+
+static bool pointInTriangle(const Vector2 & p, const Vector2 & a, const Vector2 & b, const Vector2 & c)
+{
+    return triangleArea(a, b, p) >= 0.00001f && 
+        triangleArea(b, c, p) >= 0.00001f && 
+        triangleArea(c, a, p) >= 0.00001f; 
+}
+
+
+// This is doing a simple ear-clipping algorithm that skips invalid triangles. Ideally, we should
+// also sort the ears by angle, start with the ones that have the smallest angle and proceed in order.
+HalfEdge::Mesh * nv::triangulate(const HalfEdge::Mesh * inputMesh)
+{
+    HalfEdge::Mesh * mesh = new HalfEdge::Mesh;
+    
+    // Add all vertices.
+    const uint vertexCount = inputMesh->vertexCount();
+    for (uint v = 0; v < vertexCount; v++) {
+        const HalfEdge::Vertex * vertex = inputMesh->vertexAt(v);
+        mesh->addVertex(vertex->pos);
+    }
+
+    Array<int> polygonVertices;
+    Array<float> polygonAngles;
+    Array<Vector2> polygonPoints;
+
+    const uint faceCount = inputMesh->faceCount();
+    for (uint f = 0; f < faceCount; f++)
+    {
+        const HalfEdge::Face * face = inputMesh->faceAt(f);
+        nvDebugCheck(face != NULL);
+
+        const uint edgeCount = face->edgeCount();
+        nvDebugCheck(edgeCount >= 3);
+
+        polygonVertices.clear();
+        polygonVertices.reserve(edgeCount);
+
+        if (edgeCount == 3) {
+            // Simple case for triangles.
+            for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+            {
+                const HalfEdge::Edge * edge = it.current();
+                const HalfEdge::Vertex * vertex = edge->vertex;
+                polygonVertices.append(vertex->id);
+            }
+
+            int v0 = polygonVertices[0];
+            int v1 = polygonVertices[1];
+            int v2 = polygonVertices[2];
+
+            mesh->addFace(v0, v1, v2);
+        }
+        else {
+            // Build 2D polygon projecting vertices onto normal plane.
+            // Faces are not necesarily planar, this is for example the case, when the face comes from filling a hole. In such cases
+            // it's much better to use the best fit plane.
+            const Vector3 fn = face->normal();
+
+            Basis basis;
+            basis.buildFrameForDirection(fn);
+
+            polygonPoints.clear();
+            polygonPoints.reserve(edgeCount);
+            polygonAngles.clear();
+            polygonAngles.reserve(edgeCount);
+
+            for (HalfEdge::Face::ConstEdgeIterator it(face->edges()); !it.isDone(); it.advance())
+            {
+                const HalfEdge::Edge * edge = it.current();
+                const HalfEdge::Vertex * vertex = edge->vertex;
+                polygonVertices.append(vertex->id);
+                
+                Vector2 p;
+                p.x = dot(basis.tangent, vertex->pos);
+                p.y = dot(basis.bitangent, vertex->pos);
+
+                polygonPoints.append(p);
+            }
+            polygonAngles.resize(edgeCount);
+
+            while (polygonVertices.size() > 2) {
+                uint size = polygonVertices.size();
+
+                // Update polygon angles. @@ Update only those that have changed.
+                float minAngle = 2 * PI;
+                uint bestEar = 0; // Use first one if none of them is valid.
+                bool bestIsValid = false;
+                for (uint i = 0; i < size; i++) {
+                    uint i0 = i; 
+                    uint i1 = (i+1) % size; // Use Sean's polygon interation trick.
+                    uint i2 = (i+2) % size;
+
+                    Vector2 p0 = polygonPoints[i0];
+                    Vector2 p1 = polygonPoints[i1];
+                    Vector2 p2 = polygonPoints[i2];
+
+                    float d = clamp(dot(p0-p1, p2-p1) / (length(p0-p1) * length(p2-p1)), -1.0f, 1.0f);
+                    float angle = acosf(d);
+                    
+                    float area = triangleArea(p0, p1, p2);
+                    if (area < 0.0f) angle = 2.0f * PI - angle;
+
+                    polygonAngles[i1] = angle;
+
+                    if (angle < minAngle || !bestIsValid) {
+
+                        // Make sure this is a valid ear, if not, skip this point.
+                        bool valid = true;
+                        for (uint j = 0; j < size; j++) {
+                            if (j == i0 || j == i1 || j == i2) continue;
+                            Vector2 p = polygonPoints[j];
+
+                            if (pointInTriangle(p, p0, p1, p2)) {
+                                valid = false;
+                                break;
+                            }
+                        }
+
+                        if (valid || !bestIsValid) {
+                            minAngle = angle;
+                            bestEar = i1;
+                            bestIsValid = valid;
+                        }
+                    }
+                }
+
+                nvDebugCheck(minAngle <= 2 * PI);
+
+                // Clip best ear:
+
+                uint i0 = (bestEar+size-1) % size;
+                uint i1 = (bestEar+0) % size;
+                uint i2 = (bestEar+1) % size;
+
+                int v0 = polygonVertices[i0];
+                int v1 = polygonVertices[i1];
+                int v2 = polygonVertices[i2];
+                
+                mesh->addFace(v0, v1, v2);
+
+                polygonVertices.removeAt(i1);
+                polygonPoints.removeAt(i1);
+                polygonAngles.removeAt(i1);
+            }
+        }
+
+#if 0
+
+        uint i = 0;
+        while (polygonVertices.size() > 2 && i < polygonVertices.size()) {
+            uint size = polygonVertices.size();
+            uint i0 = (i+0) % size;
+            uint i1 = (i+1) % size;
+            uint i2 = (i+2) % size;
+
+            const HalfEdge::Vertex * v0 = polygonVertices[i0];
+            const HalfEdge::Vertex * v1 = polygonVertices[i1];
+            const HalfEdge::Vertex * v2 = polygonVertices[i2];
+
+            const Vector3 p0 = v0->pos;
+            const Vector3 p1 = v1->pos;
+            const Vector3 p2 = v2->pos;
+
+            const Vector3 e0 = p2 - p1;
+            const Vector3 e1 = p0 - p1;
+
+            // If this ear forms a valid triangle, setup relations, remove v1 and repeat.
+            Vector3 n = cross(e0, e1);
+            float len = dot(fn, n); // = sin(angle)
+            
+            float angle = asin(len);
+
+
+            if (len > 0.0f) {
+                mesh->addFace(v0->id(), v1->id(), v2->id());
+                polygonVertices.removeAt(i1);
+                polygonAngles.removeAt(i1);
+                if (i2 > i1) i2--;
+                // @@ Update angles at i0 and i2
+            }
+            else {
+                i++;
+            }
+        }
+
+        // @@ Create a few degenerate triangles to avoid introducing holes.
+        i = 0;
+        const uint size = polygonVertices.size();
+        while (i < size - 2) {
+            uint i0 = (i+0) % size;
+            uint i1 = (i+1) % size;
+            uint i2 = (i+2) % size;
+
+            const HalfEdge::Vertex * v0 = polygonVertices[i0];
+            const HalfEdge::Vertex * v1 = polygonVertices[i1];
+            const HalfEdge::Vertex * v2 = polygonVertices[i2];
+
+            mesh->addFace(v0->id(), v1->id(), v2->id());
+            i++;
+        }
+#endif
+    }
+
+    mesh->linkBoundary();
+
+    return mesh;
+}
+
+
diff --git a/thirdparty/thekla_atlas/nvmesh/param/Util.h b/thirdparty/thekla_atlas/nvmesh/param/Util.h
new file mode 100644
index 0000000000..774563ac0b
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/param/Util.h
@@ -0,0 +1,18 @@
+// This code is in the public domain -- castano@gmail.com
+
+#include "nvmesh/nvmesh.h"
+
+namespace nv {
+
+    namespace HalfEdge { class Mesh; class Vertex; }
+
+    bool isQuadMesh(const HalfEdge::Mesh * mesh);
+    bool isTriangularMesh(const HalfEdge::Mesh * mesh);
+
+    uint countMeshTriangles(const HalfEdge::Mesh * mesh);
+    const HalfEdge::Vertex * findBoundaryVertex(const HalfEdge::Mesh * mesh);
+
+    HalfEdge::Mesh * unifyVertices(const HalfEdge::Mesh * inputMesh);
+    HalfEdge::Mesh * triangulate(const HalfEdge::Mesh * inputMesh);
+
+} // nv namespace
diff --git a/thirdparty/thekla_atlas/nvmesh/raster/ClippedTriangle.h b/thirdparty/thekla_atlas/nvmesh/raster/ClippedTriangle.h
new file mode 100644
index 0000000000..0947d4851c
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/raster/ClippedTriangle.h
@@ -0,0 +1,159 @@
+// Copyright NVIDIA Corporation 2007 -- Denis Kovacs <den.kovacs@gmail.com>
+
+#pragma once
+#ifndef NV_MESH_CLIPPEDTRIANGLE_H
+#define NV_MESH_CLIPPEDTRIANGLE_H
+
+#include <nvmath/Vector.h>
+
+namespace nv
+{
+
+    class ClippedTriangle
+    {
+    public:
+        ClippedTriangle(Vector2::Arg a, Vector2::Arg b, Vector2::Arg c) 
+        {
+            m_numVertices = 3;
+            m_activeVertexBuffer = 0;
+
+            m_verticesA[0]=a;
+            m_verticesA[1]=b;
+            m_verticesA[2]=c;
+
+            m_vertexBuffers[0] = m_verticesA;
+            m_vertexBuffers[1] = m_verticesB;
+        }
+
+        uint vertexCount()
+        {
+            return m_numVertices;
+        }
+
+        const Vector2 * vertices()
+        {
+            return m_vertexBuffers[m_activeVertexBuffer];
+        }
+
+        inline void clipHorizontalPlane(float offset, float clipdirection) 
+        {
+            Vector2 * v  = m_vertexBuffers[m_activeVertexBuffer];
+            m_activeVertexBuffer ^= 1;
+            Vector2 * v2 = m_vertexBuffers[m_activeVertexBuffer];
+
+            v[m_numVertices] = v[0];
+
+            float dy2,   dy1 = offset - v[0].y;
+            int   dy2in, dy1in = clipdirection*dy1 >= 0;
+            uint  p=0;
+
+            for (uint k=0; k<m_numVertices; k++)
+            {
+                dy2   = offset - v[k+1].y;
+                dy2in = clipdirection*dy2 >= 0;
+
+                if (dy1in) v2[p++] = v[k];
+
+                if ( dy1in + dy2in == 1 ) // not both in/out
+                {
+                    float dx = v[k+1].x - v[k].x;
+                    float dy = v[k+1].y - v[k].y;
+                    v2[p++] = Vector2(v[k].x + dy1*(dx/dy), offset);
+                }
+
+                dy1 = dy2; dy1in = dy2in;
+            }
+            m_numVertices = p;
+
+            //for (uint k=0; k<m_numVertices; k++) printf("(%f, %f)\n", v2[k].x, v2[k].y); printf("\n");
+        }
+
+        inline void clipVerticalPlane(float offset, float clipdirection ) 
+        {
+            Vector2 * v  = m_vertexBuffers[m_activeVertexBuffer];
+            m_activeVertexBuffer ^= 1;
+            Vector2 * v2 = m_vertexBuffers[m_activeVertexBuffer];
+
+            v[m_numVertices] = v[0];
+
+            float dx2,   dx1   = offset - v[0].x;
+            int   dx2in, dx1in = clipdirection*dx1 >= 0;
+            uint  p=0;
+
+            for (uint k=0; k<m_numVertices; k++)
+            {
+                dx2 = offset - v[k+1].x;
+                dx2in = clipdirection*dx2 >= 0;
+
+                if (dx1in) v2[p++] = v[k];
+
+                if ( dx1in + dx2in == 1 ) // not both in/out
+                {
+                    float dx = v[k+1].x - v[k].x;
+                    float dy = v[k+1].y - v[k].y;
+                    v2[p++] = Vector2(offset, v[k].y + dx1*(dy/dx));
+                }
+
+                dx1 = dx2; dx1in = dx2in;
+            }
+            m_numVertices = p;
+
+            //for (uint k=0; k<m_numVertices; k++) printf("(%f, %f)\n", v2[k].x, v2[k].y); printf("\n");
+        }
+
+        void computeAreaCentroid()
+        {
+            Vector2 * v  = m_vertexBuffers[m_activeVertexBuffer];
+            v[m_numVertices] = v[0];
+
+            m_area = 0;
+            float centroidx=0, centroidy=0;
+            for (uint k=0; k<m_numVertices; k++)
+            {
+                // http://local.wasp.uwa.edu.au/~pbourke/geometry/polyarea/
+                float f = v[k].x*v[k+1].y - v[k+1].x*v[k].y;
+                m_area += f;
+                centroidx += f * (v[k].x + v[k+1].x);
+                centroidy += f * (v[k].y + v[k+1].y);
+            }
+            m_area = 0.5f * fabs(m_area);
+            if (m_area==0) {
+                m_centroid = Vector2(0.0f);
+            } else {
+                m_centroid = Vector2(centroidx/(6*m_area), centroidy/(6*m_area));
+            }
+        }
+
+        void clipAABox(float x0, float y0, float x1, float y1)
+        {
+            clipVerticalPlane  ( x0, -1);
+            clipHorizontalPlane( y0, -1);
+            clipVerticalPlane  ( x1,  1);
+            clipHorizontalPlane( y1,  1);
+
+            computeAreaCentroid();
+        }
+
+        Vector2 centroid()
+        {
+            return m_centroid;
+        }
+
+        float area()
+        {
+            return m_area;
+        }
+
+    private:
+        Vector2 m_verticesA[7+1];
+        Vector2 m_verticesB[7+1];
+        Vector2 * m_vertexBuffers[2];
+        uint    m_numVertices;
+        uint    m_activeVertexBuffer;
+        float   m_area;
+        Vector2 m_centroid;
+    };
+
+} // nv namespace
+
+#endif // NV_MESH_CLIPPEDTRIANGLE_H
diff --git a/thirdparty/thekla_atlas/nvmesh/raster/Raster.cpp b/thirdparty/thekla_atlas/nvmesh/raster/Raster.cpp
new file mode 100644
index 0000000000..d46b34f045
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/raster/Raster.cpp
@@ -0,0 +1,626 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+/** @file Raster.cpp
+ * @brief Triangle rasterization library using affine interpolation. Not
+ * specially optimized, but enough for my purposes.
+**/
+
+#include "nvmesh.h" // pch
+
+#include "Raster.h"
+#include "ClippedTriangle.h"
+
+#include "nvcore/Utils.h" // min, max
+
+#include "nvmath/Vector.inl"
+#include "nvmath/ftoi.h"
+
+
+#define RA_EPSILON		0.00001f
+
+using namespace nv;
+using namespace nv::Raster;
+
+namespace
+{
+    static inline float delta(float bot, float top, float ih)
+    {
+        return (bot - top) * ih;
+    }
+
+    static inline Vector2 delta(Vector2::Arg bot, Vector2::Arg top, float ih)
+    {
+        return (bot - top) * ih;
+    }
+
+    static inline Vector3 delta(Vector3::Arg bot, Vector3::Arg top, float ih)
+    {
+        return (bot - top) * ih;
+    }
+
+    // @@ The implementation in nvmath.h should be equivalent.
+    static inline int iround(float f)
+    {
+        // @@ Optimize this.
+        return int(floorf(f+0.5f));
+        //return int(round(f));
+        //return int(f);
+    }
+
+    /// A triangle vertex. 
+    struct Vertex
+    {
+        Vector2 pos;	// Position.
+        Vector3 tex;	// Texcoord. (Barycentric coordinate)
+    };
+
+
+    /// A triangle for rasterization.
+    struct Triangle
+    {
+        Triangle(Vector2::Arg v0, Vector2::Arg v1, Vector2::Arg v2, Vector3::Arg t0, Vector3::Arg t1, Vector3::Arg t2);
+
+        bool computeDeltas();
+
+        bool draw(const Vector2 & extents, bool enableScissors, SamplingCallback cb, void * param);
+        bool drawAA(const Vector2 & extents, bool enableScissors, SamplingCallback cb, void * param);
+        bool drawC(const Vector2 & extents, bool enableScissors, SamplingCallback cb, void * param);
+        void flipBackface();
+        void computeUnitInwardNormals();
+
+        // Vertices.	
+        Vector2 v1, v2, v3;
+        Vector2 n1, n2, n3; // unit inward normals
+        Vector3 t1, t2, t3;
+
+        // Deltas.
+        Vector3 dx, dy;
+
+        float sign;
+        bool valid;
+    };
+
+
+    /// Triangle ctor.
+    Triangle::Triangle(Vector2::Arg v0, Vector2::Arg v1, Vector2::Arg v2, 
+        Vector3::Arg t0, Vector3::Arg t1, Vector3::Arg t2)
+    {
+        // Init vertices.
+        this->v1 = v0;
+        this->v2 = v2;
+        this->v3 = v1;
+
+        // Set barycentric coordinates.
+        this->t1 = t0;
+        this->t2 = t2;
+        this->t3 = t1;
+
+        // make sure every triangle is front facing.
+        flipBackface();
+
+        // Compute deltas.
+        valid = computeDeltas();
+
+        computeUnitInwardNormals();
+    }
+
+
+    /// Compute texture space deltas.
+    /// This method takes two edge vectors that form a basis, determines the 
+    /// coordinates of the canonic vectors in that basis, and computes the 
+    /// texture gradient that corresponds to those vectors.
+    bool Triangle::computeDeltas()
+    {
+        Vector2 e0 = v3 - v1;
+        Vector2 e1 = v2 - v1;
+
+        Vector3 de0 = t3 - t1;
+        Vector3 de1 = t2 - t1;
+
+        float denom = 1.0f / (e0.y * e1.x - e1.y * e0.x);
+        if (!isFinite(denom)) {
+            return false;
+        }
+
+        float lambda1 = - e1.y * denom;
+        float lambda2 = e0.y * denom;
+        float lambda3 = e1.x * denom;
+        float lambda4 = - e0.x * denom;
+
+        dx = de0 * lambda1 + de1 * lambda2;
+        dy = de0 * lambda3 + de1 * lambda4;
+
+        return true;
+    }
+
+    // compute unit inward normals for each edge.
+    void Triangle::computeUnitInwardNormals()
+    {
+        n1 = v1 - v2; n1 = Vector2(-n1.y, n1.x); n1 = n1 * (1.0f/sqrtf(n1.x*n1.x + n1.y*n1.y));
+        n2 = v2 - v3; n2 = Vector2(-n2.y, n2.x); n2 = n2 * (1.0f/sqrtf(n2.x*n2.x + n2.y*n2.y));
+        n3 = v3 - v1; n3 = Vector2(-n3.y, n3.x); n3 = n3 * (1.0f/sqrtf(n3.x*n3.x + n3.y*n3.y));
+    }
+
+    void Triangle::flipBackface()
+    {
+        // check if triangle is backfacing, if so, swap two vertices
+        if ( ((v3.x-v1.x)*(v2.y-v1.y) - (v3.y-v1.y)*(v2.x-v1.x)) < 0 ) {
+            Vector2 hv=v1; v1=v2; v2=hv; // swap pos
+            Vector3 ht=t1; t1=t2; t2=ht; // swap tex
+        }
+    }
+
+    bool Triangle::draw(const Vector2 & extents, bool enableScissors, SamplingCallback cb, void * param)
+    {
+        // 28.4 fixed-point coordinates
+        const int Y1 = iround(16.0f * v1.y);
+        const int Y2 = iround(16.0f * v2.y);
+        const int Y3 = iround(16.0f * v3.y);
+
+        const int X1 = iround(16.0f * v1.x);
+        const int X2 = iround(16.0f * v2.x);
+        const int X3 = iround(16.0f * v3.x);
+
+        // Deltas
+        const int DX12 = X1 - X2;
+        const int DX23 = X2 - X3;
+        const int DX31 = X3 - X1;
+
+        const int DY12 = Y1 - Y2;
+        const int DY23 = Y2 - Y3;
+        const int DY31 = Y3 - Y1;
+
+        // Fixed-point deltas
+        const int FDX12 = DX12 << 4;
+        const int FDX23 = DX23 << 4;
+        const int FDX31 = DX31 << 4;
+
+        const int FDY12 = DY12 << 4;
+        const int FDY23 = DY23 << 4;
+        const int FDY31 = DY31 << 4;
+
+        int minx, miny, maxx, maxy;
+        if (enableScissors) {
+            int frustumX0 =  0 << 4;
+            int frustumY0 =  0 << 4;
+            int frustumX1 =  (int)extents.x << 4;
+            int frustumY1 =  (int)extents.y << 4;
+
+            // Bounding rectangle
+            minx = (nv::max(min3(X1, X2, X3), frustumX0) + 0xF) >> 4;
+            miny = (nv::max(min3(Y1, Y2, Y3), frustumY0) + 0xF) >> 4;
+            maxx = (nv::min(max3(X1, X2, X3), frustumX1) + 0xF) >> 4;
+            maxy = (nv::min(max3(Y1, Y2, Y3), frustumY1) + 0xF) >> 4;
+        }
+        else {
+            // Bounding rectangle
+            minx = (min3(X1, X2, X3) + 0xF) >> 4;
+            miny = (min3(Y1, Y2, Y3) + 0xF) >> 4;
+            maxx = (max3(X1, X2, X3) + 0xF) >> 4;
+            maxy = (max3(Y1, Y2, Y3) + 0xF) >> 4;
+        }
+
+        // Block size, standard 8x8 (must be power of two)
+        const int q = 8;
+
+        // @@ This won't work when minx,miny are negative. This code path is not used. Leaving as is for now.
+        nvCheck(minx >= 0);
+        nvCheck(miny >= 0);
+
+        // Start in corner of 8x8 block
+        minx &= ~(q - 1);
+        miny &= ~(q - 1);
+
+        // Half-edge constants
+        int C1 = DY12 * X1 - DX12 * Y1;
+        int C2 = DY23 * X2 - DX23 * Y2;
+        int C3 = DY31 * X3 - DX31 * Y3;
+
+        // Correct for fill convention
+        if(DY12 < 0 || (DY12 == 0 && DX12 > 0)) C1++;
+        if(DY23 < 0 || (DY23 == 0 && DX23 > 0)) C2++;
+        if(DY31 < 0 || (DY31 == 0 && DX31 > 0)) C3++;
+
+        // Loop through blocks
+        for(int y = miny; y < maxy; y += q)
+        {
+            for(int x = minx; x < maxx; x += q)
+            {
+                // Corners of block
+                int x0 = x << 4;
+                int x1 = (x + q - 1) << 4;
+                int y0 = y << 4;
+                int y1 = (y + q - 1) << 4;
+
+                // Evaluate half-space functions
+                bool a00 = C1 + DX12 * y0 - DY12 * x0 > 0;
+                bool a10 = C1 + DX12 * y0 - DY12 * x1 > 0;
+                bool a01 = C1 + DX12 * y1 - DY12 * x0 > 0;
+                bool a11 = C1 + DX12 * y1 - DY12 * x1 > 0;
+                int a = (a00 << 0) | (a10 << 1) | (a01 << 2) | (a11 << 3);
+
+                bool b00 = C2 + DX23 * y0 - DY23 * x0 > 0;
+                bool b10 = C2 + DX23 * y0 - DY23 * x1 > 0;
+                bool b01 = C2 + DX23 * y1 - DY23 * x0 > 0;
+                bool b11 = C2 + DX23 * y1 - DY23 * x1 > 0;
+                int b = (b00 << 0) | (b10 << 1) | (b01 << 2) | (b11 << 3);
+
+                bool c00 = C3 + DX31 * y0 - DY31 * x0 > 0;
+                bool c10 = C3 + DX31 * y0 - DY31 * x1 > 0;
+                bool c01 = C3 + DX31 * y1 - DY31 * x0 > 0;
+                bool c11 = C3 + DX31 * y1 - DY31 * x1 > 0;
+                int c = (c00 << 0) | (c10 << 1) | (c01 << 2) | (c11 << 3);
+
+                // Skip block when outside an edge
+                if(a == 0x0 || b == 0x0 || c == 0x0) continue;		
+
+                // Accept whole block when totally covered
+                if(a == 0xF && b == 0xF && c == 0xF)
+                {
+                    Vector3 texRow = t1 + dy*(y0 - v1.y) + dx*(x0 - v1.x);
+
+                    for(int iy = y; iy < y + q; iy++)
+                    {
+                        Vector3 tex = texRow;
+                        for(int ix = x; ix < x + q; ix++)
+                        {
+                            //Vector3 tex = t1 + dx * (ix - v1.x) + dy * (iy - v1.y);
+                            if (!cb(param, ix, iy, tex, dx, dy, 1.0)) {
+                                // early out.
+                                return false;
+                            }
+                            tex += dx;
+                        }
+                        texRow += dy;
+                    }
+                }
+                else // Partially covered block
+                {
+                    int CY1 = C1 + DX12 * y0 - DY12 * x0;
+                    int CY2 = C2 + DX23 * y0 - DY23 * x0;
+                    int CY3 = C3 + DX31 * y0 - DY31 * x0;
+                    Vector3 texRow = t1 + dy*(y0 - v1.y) + dx*(x0 - v1.x);
+
+                    for(int iy = y; iy < y + q; iy++)
+                    {
+                        int CX1 = CY1;
+                        int CX2 = CY2;
+                        int CX3 = CY3;
+                        Vector3 tex = texRow;
+
+                        for(int ix = x; ix < x + q; ix++)
+                        {
+                            if(CX1 > 0 && CX2 > 0 && CX3 > 0)
+                            {
+                                if (!cb(param, ix, iy, tex, dx, dy, 1.0))
+                                {
+                                    // early out.
+                                    return false;
+                                }
+                            }
+
+                            CX1 -= FDY12;
+                            CX2 -= FDY23;
+                            CX3 -= FDY31;
+                            tex += dx;
+                        }
+
+                        CY1 += FDX12;
+                        CY2 += FDX23;
+                        CY3 += FDX31;
+                        texRow += dy;
+                    }
+                }
+            }
+        }
+
+        return true;
+    }
+
+
+#define PX_INSIDE    1.0f/sqrt(2.0f)
+#define PX_OUTSIDE  -1.0f/sqrt(2.0f)
+
+#define BK_SIZE 8
+#define BK_INSIDE   sqrt(BK_SIZE*BK_SIZE/2.0f)
+#define BK_OUTSIDE -sqrt(BK_SIZE*BK_SIZE/2.0f)
+
+    // extents has to be multiple of BK_SIZE!!
+    bool Triangle::drawAA(const Vector2 & extents, bool enableScissors, SamplingCallback cb, void * param)
+    {
+        float minx, miny, maxx, maxy;
+        if (enableScissors) {
+            // Bounding rectangle
+            minx = floorf(max(min3(v1.x, v2.x, v3.x), 0.0f));
+            miny = floorf(max(min3(v1.y, v2.y, v3.y), 0.0f));
+            maxx = ceilf( min(max3(v1.x, v2.x, v3.x), extents.x-1.0f));
+            maxy = ceilf( min(max3(v1.y, v2.y, v3.y), extents.y-1.0f));
+        }
+        else {
+            // Bounding rectangle
+            minx = floorf(min3(v1.x, v2.x, v3.x));
+            miny = floorf(min3(v1.y, v2.y, v3.y));
+            maxx = ceilf( max3(v1.x, v2.x, v3.x));
+            maxy = ceilf( max3(v1.y, v2.y, v3.y));
+        }
+
+        // There's no reason to align the blocks to the viewport, instead we align them to the origin of the triangle bounds.
+        minx = floorf(minx);
+        miny = floorf(miny);
+        //minx = (float)(((int)minx) & (~((int)BK_SIZE - 1))); // align to blocksize (we don't need to worry about blocks partially out of viewport)
+        //miny = (float)(((int)miny) & (~((int)BK_SIZE - 1)));
+
+        minx += 0.5; miny +=0.5;  // sampling at texel centers!
+        maxx += 0.5; maxy +=0.5; 
+
+        // Half-edge constants
+        float C1 = n1.x * (-v1.x) + n1.y * (-v1.y);
+        float C2 = n2.x * (-v2.x) + n2.y * (-v2.y);
+        float C3 = n3.x * (-v3.x) + n3.y * (-v3.y);
+
+        // Loop through blocks
+        for(float y0 = miny; y0 <= maxy; y0 += BK_SIZE)
+        {
+            for(float x0 = minx; x0 <= maxx; x0 += BK_SIZE)
+            {
+                // Corners of block
+                float xc = (x0 + (BK_SIZE-1)/2.0f);
+                float yc = (y0 + (BK_SIZE-1)/2.0f);
+
+                // Evaluate half-space functions
+                float aC = C1 + n1.x * xc + n1.y * yc;
+                float bC = C2 + n2.x * xc + n2.y * yc;
+                float cC = C3 + n3.x * xc + n3.y * yc;
+
+                // Skip block when outside an edge
+                if( (aC <= BK_OUTSIDE) || (bC <= BK_OUTSIDE) || (cC <= BK_OUTSIDE) ) continue;
+
+                // Accept whole block when totally covered
+                if( (aC >= BK_INSIDE) && (bC >= BK_INSIDE) && (cC >= BK_INSIDE) )
+                {
+                    Vector3 texRow = t1 + dy*(y0 - v1.y) + dx*(x0 - v1.x);
+
+                    for (float y = y0; y < y0 + BK_SIZE; y++)
+                    {
+                        Vector3 tex = texRow;
+                        for(float x = x0; x < x0 + BK_SIZE; x++)
+                        {
+                            if (!cb(param, (int)x, (int)y, tex, dx, dy, 1.0f))
+                            {
+                                return false;
+                            }
+                            tex += dx;
+                        }
+                        texRow += dy;
+                    }
+                }
+                else // Partially covered block
+                {
+                    float CY1 = C1 + n1.x * x0 + n1.y * y0;
+                    float CY2 = C2 + n2.x * x0 + n2.y * y0;
+                    float CY3 = C3 + n3.x * x0 + n3.y * y0;
+                    Vector3 texRow = t1 + dy*(y0 - v1.y) + dx*(x0 - v1.x);	                  	
+
+                    for(float y = y0; y < y0 + BK_SIZE; y++) // @@ This is not clipping to scissor rectangle correctly.
+                    {
+                        float CX1 = CY1;
+                        float CX2 = CY2;
+                        float CX3 = CY3;
+                        Vector3 tex = texRow;
+
+                        for (float x = x0; x < x0 + BK_SIZE; x++)   // @@ This is not clipping to scissor rectangle correctly.
+                        {
+                            if (CX1 >= PX_INSIDE && CX2 >= PX_INSIDE && CX3 >= PX_INSIDE) 
+                            {
+                                // pixel completely covered
+                                Vector3 tex = t1 + dx * (x - v1.x) + dy * (y - v1.y);
+                                if (!cb(param, (int)x, (int)y, tex, dx, dy, 1.0f))
+                                {
+                                    return false;
+                                }
+                            }
+                            else if ((CX1 >= PX_OUTSIDE) && (CX2 >= PX_OUTSIDE) && (CX3 >= PX_OUTSIDE))
+                            {
+                                // triangle partially covers pixel. do clipping.
+                                ClippedTriangle ct(v1-Vector2(x,y), v2-Vector2(x,y), v3-Vector2(x,y));
+                                ct.clipAABox(-0.5, -0.5, 0.5, 0.5);
+                                Vector2 centroid = ct.centroid();
+                                float area = ct.area();
+                                if (area > 0.0f)
+                                {
+                                    Vector3 texCent = tex - dx*centroid.x - dy*centroid.y;
+                                    //nvCheck(texCent.x >= -0.1f && texCent.x <= 1.1f); // @@ Centroid is not very exact...
+                                    //nvCheck(texCent.y >= -0.1f && texCent.y <= 1.1f);
+                                    //nvCheck(texCent.z >= -0.1f && texCent.z <= 1.1f);
+                                    //Vector3 texCent2 = t1 + dx * (x - v1.x) + dy * (y - v1.y);
+                                    if (!cb(param, (int)x, (int)y, texCent, dx, dy, area))
+                                    {
+                                        return false;
+                                    }
+                                }
+                            }
+
+                            CX1 += n1.x;
+                            CX2 += n2.x;
+                            CX3 += n3.x;
+                            tex += dx;
+                        }
+
+                        CY1 += n1.y;
+                        CY2 += n2.y;
+                        CY3 += n3.y;
+                        texRow += dy;
+                    }
+                }
+            }
+        }
+
+        return true;
+    }
+
+} // namespace
+
+
+/// Process the given triangle.
+bool nv::Raster::drawTriangle(Mode mode, Vector2::Arg extents, bool enableScissors, const Vector2 v[3], SamplingCallback cb, void * param)
+{
+    Triangle tri(v[0], v[1], v[2], Vector3(1, 0, 0), Vector3(0, 1, 0), Vector3(0, 0, 1));
+    
+    // @@ It would be nice to have a conservative drawing mode that enlarges the triangle extents by one texel and is able to handle degenerate triangles.
+    // @@ Maybe the simplest thing to do would be raster triangle edges.
+
+    if (tri.valid) {
+        if (mode == Mode_Antialiased) {
+            return tri.drawAA(extents, enableScissors, cb, param);
+        } 
+        if (mode == Mode_Nearest) {
+            return tri.draw(extents, enableScissors, cb, param);
+        }
+    }
+
+    return true;
+}
+
+inline static float triangleArea(Vector2::Arg v1, Vector2::Arg v2, Vector2::Arg v3)
+{
+    return 0.5f * (v3.x * v1.y + v1.x * v2.y + v2.x * v3.y - v2.x * v1.y - v3.x * v2.y - v1.x * v3.y);
+}
+
+/// Process the given quad.
+bool nv::Raster::drawQuad(Mode mode, Vector2::Arg extents, bool enableScissors, const Vector2 v[4], SamplingCallback cb, void * param)
+{
+    bool sign0 = triangleArea(v[0], v[1], v[2]) > 0.0f;
+    bool sign1 = triangleArea(v[0], v[2], v[3]) > 0.0f;
+
+    // Divide the quad into two non overlapping triangles.
+    if (sign0 == sign1) {
+        Triangle tri0(v[0], v[1], v[2], Vector3(0,0,0), Vector3(1,0,0), Vector3(1,1,0));
+        Triangle tri1(v[0], v[2], v[3], Vector3(0,0,0), Vector3(1,1,0), Vector3(0,1,0));
+
+        if (tri0.valid && tri1.valid) {
+            if (mode == Mode_Antialiased) {
+                return tri0.drawAA(extents, enableScissors, cb, param) && tri1.drawAA(extents, enableScissors, cb, param);
+            } else {
+                return tri0.draw(extents, enableScissors, cb, param) && tri1.draw(extents, enableScissors, cb, param);
+            }
+        }
+    }
+    else
+    {
+        Triangle tri0(v[0], v[1], v[3], Vector3(0,0,0), Vector3(1,0,0), Vector3(0,1,0));
+        Triangle tri1(v[1], v[2], v[3], Vector3(1,0,0), Vector3(1,1,0), Vector3(0,1,0));
+
+        if (tri0.valid && tri1.valid) {
+            if (mode == Mode_Antialiased) {
+                return tri0.drawAA(extents, enableScissors, cb, param) && tri1.drawAA(extents, enableScissors, cb, param);
+            } else {
+                return tri0.draw(extents, enableScissors, cb, param) && tri1.draw(extents, enableScissors, cb, param);
+            }
+        }
+    }
+
+    return true;
+}
+
+
+static bool drawPoint(const Vector2 & p, const Vector2 v[2], LineSamplingCallback cb, void * param) {
+
+    int x = ftoi_round(p.x);
+    int y = ftoi_round(p.y);
+    Vector2 ip = Vector2(float(x) + 0.5f, float(y) + 0.5f);
+
+    float t;
+
+    // Return minimum distance between line segment vw and point p
+    Vector2 dv = v[1] - v[0];
+    const float l2 = nv::lengthSquared(dv);  // i.e. |w-v|^2 -  avoid a sqrt
+    if (l2 == 0.0) {
+        t = 0;                  // v0 == v1 case
+    }
+    else {
+        // Consider the line extending the segment, parameterized as v + t (w - v).
+        // We find projection of point p onto the line. 
+        // It falls where t = [(p-v) . (w-v)] / |w-v|^2
+        t = dot(ip - v[0], dv) / l2;
+        if (t < 0.0) {
+            t = 0;                      // Beyond the 'v0' end of the segment
+        }
+        else if (t > 1.0) {
+            t = 1;                      // Beyond the 'v1' end of the segment
+        }
+    }
+    
+    Vector2 projection = v[0] + t * dv; // Projection falls on the segment
+
+    float d = distance(ip, projection);
+
+    return cb(param, x, y, t, saturate(1-d));
+}
+
+
+void nv::Raster::drawLine(bool antialias, Vector2::Arg extents, bool enableScissors, const Vector2 v[2], LineSamplingCallback cb, void * param)
+{
+    nvCheck(antialias == true);         // @@ Not implemented.
+    //nvCheck(enableScissors == false); // @@ Not implemented.
+
+    // Very crappy DDA implementation.
+
+    Vector2 p = v[0];
+    Vector2 dp, dpdy;
+
+    float dx = v[1].x - v[0].x;
+    float dy = v[1].y - v[0].y;
+    int n;
+
+    // Degenerate line.
+    if (dx == 0 && dy == 0) return;
+
+    if (fabsf(dx) >= fabsf(dy)) {
+        n = iround(fabsf(dx));
+        dp.x = dx / fabsf(dx);
+        dp.y = dy / fabsf(dx);
+        nvDebugCheck(fabsf(dp.y) <= 1.0f);
+        dpdy.x = 0;
+        dpdy.y = 1;
+    }
+    else {
+        n = iround(fabs(dy));
+        dp.x = dx / fabsf(dy);
+        dp.y = dy / fabsf(dy);
+        nvDebugCheck(fabsf(dp.x) <= 1.0f);
+        dpdy.x = 1;
+        dpdy.y = 0;
+    }
+
+    for (int i = 0; i <= n; i++) {
+        drawPoint(p, v, cb, param);
+        drawPoint(p + dpdy, v, cb, param);
+        drawPoint(p - dpdy, v, cb, param);
+        p += dp;
+    }
+}
+
+
+// Draw vertical or horizontal segments. For degenerate triangles.
+/*bool nv::Raster::drawSegment(Vector2::Arg extents, bool enableScissors, const Vector2 v[2], LineSamplingCallback cb, void * param)
+{
+    nvCheck(enableScissors == false);
+
+    
+    if (v[0].x == v[1].x) {         // Vertical segment.
+        
+    }
+    else if (v[0].y == v[1].y) {    // Horizontal segment.
+        int y = ftoi_round(v[0].y);
+        int x0 = ftoi_floor(v[0].x);
+        int x1 = ftoi_floor(v[0].x);
+
+        for (int x = x0; x <= x1; x++) {
+
+            cb(param, x, y, t, 
+        }
+    }
+
+    return false; // Not a valid segment.
+}
+*/
diff --git a/thirdparty/thekla_atlas/nvmesh/raster/Raster.h b/thirdparty/thekla_atlas/nvmesh/raster/Raster.h
new file mode 100644
index 0000000000..05af2ddb00
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/raster/Raster.h
@@ -0,0 +1,49 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#pragma once
+#ifndef NV_MESH_RASTER_H
+#define NV_MESH_RASTER_H
+
+/** @file Raster.h
+ * @brief Rasterization library.
+ *
+ * This is just a standard scanline rasterizer that I took from one of my old
+ * projects. The perspective correction wasn't necessary so I just removed it.
+**/
+
+#include "nvmath/Vector.h"
+#include "nvmesh/nvmesh.h"
+
+namespace nv
+{
+
+    namespace Raster 
+    {
+        enum Mode {
+            Mode_Nearest,
+            Mode_Antialiased,
+            //Mode_Conservative
+        };
+
+
+        /// A callback to sample the environment. Return false to terminate rasterization.
+        typedef bool (NV_CDECL * SamplingCallback)(void * param, int x, int y, Vector3::Arg bar, Vector3::Arg dx, Vector3::Arg dy, float coverage);
+
+        // Process the given triangle. Returns false if rasterization was interrupted by the callback.
+        NVMESH_API bool drawTriangle(Mode mode, Vector2::Arg extents, bool enableScissors, const Vector2 v[3], SamplingCallback cb, void * param);
+
+        // Process the given quad. Returns false if rasterization was interrupted by the callback.
+        NVMESH_API bool drawQuad(Mode mode, Vector2::Arg extents, bool enableScissors, const Vector2 v[4], SamplingCallback cb, void * param);
+
+        typedef bool (NV_CDECL * LineSamplingCallback)(void * param, int x, int y, float t, float d);    // t is the position along the segment, d is the distance to the line.
+
+        // Process the given line.
+        NVMESH_API void drawLine(bool antialias, Vector2::Arg extents, bool enableScissors, const Vector2 v[2], LineSamplingCallback cb, void * param);
+
+        // Draw vertical or horizontal segments. For degenerate triangles.
+        //NVMESH_API void drawSegment(Vector2::Arg extents, bool enableScissors, const Vector2 v[2], SamplingCallback cb, void * param);
+    }
+}
+
+
+#endif // NV_MESH_RASTER_H
diff --git a/thirdparty/thekla_atlas/nvmesh/weld/Snap.cpp b/thirdparty/thekla_atlas/nvmesh/weld/Snap.cpp
new file mode 100644
index 0000000000..b6bff4d83d
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/weld/Snap.cpp
@@ -0,0 +1,100 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#include <nvcore/RadixSort.h>
+
+#include <nvmesh/weld/Snap.h>
+#include <nvmesh/TriMesh.h>
+#include <nvmesh/geometry/Bounds.h>
+
+using namespace nv;
+
+namespace {
+	
+	// Snap the given vertices.
+	void Snap(TriMesh::Vertex & a, TriMesh::Vertex & b, float texThreshold, float norThreshold)
+	{
+		a.pos = b.pos = (a.pos + b.pos) * 0.5f;
+		
+		if (equal(a.tex.x, b.tex.x, texThreshold) && equal(a.tex.y, b.tex.y, texThreshold)) {
+			b.tex = a.tex = (a.tex + b.tex) * 0.5f;
+		}
+		
+		if (equal(a.nor.x, b.nor.x, norThreshold) && equal(a.nor.y, b.nor.y, norThreshold) && equal(a.nor.z, b.nor.z, norThreshold)) {
+			b.nor = a.nor = (a.nor + b.nor) * 0.5f;
+		}
+	};
+
+} // nv namespace
+
+uint nv::SnapVertices(TriMesh * mesh, float posThreshold, float texThreshold, float norThreshold)
+{
+	nvDebug("--- Snapping vertices.\n");
+	
+	// Determine largest axis.
+	Box box = MeshBounds::box(mesh);
+	Vector3 extents = box.extents();
+
+	int axis = 2;
+	if( extents.x > extents.y ) {
+		if( extents.x > extents.z ) {
+			axis = 0;
+		}
+	}
+	else if(extents.y > extents.z) {
+		axis = 1;
+	}
+	
+	// @@ Use diagonal instead!
+	
+
+	// Sort vertices according to the largest axis.
+	const uint vertexCount = mesh->vertexCount();
+	nvCheck(vertexCount > 2); // Must have at least two vertices.
+
+	// Get pos channel.
+	//PiMesh::Channel * pos_channel = mesh->GetChannel(mesh->FindChannel(VS_POS));
+	//nvCheck( pos_channel != NULL );
+
+	//const PiArray<Vec4> & pos_array = pos_channel->data;
+
+	Array<float> distArray;
+	distArray.resize(vertexCount);
+
+	for(uint v = 0; v < vertexCount; v++) {
+		if (axis == 0) distArray[v] = mesh->vertexAt(v).pos.x;
+		else if (axis == 1) distArray[v] = mesh->vertexAt(v).pos.y;
+		else distArray[v] = mesh->vertexAt(v).pos.z;
+	}
+
+	RadixSort radix;
+	const uint * xrefs = radix.sort(distArray.buffer(), distArray.count()).ranks();
+	nvCheck(xrefs != NULL);
+
+	uint snapCount = 0;
+	for(uint v = 0; v < vertexCount-1; v++) {
+		for(uint n = v+1; n < vertexCount; n++) {
+			nvDebugCheck( distArray[xrefs[v]] <= distArray[xrefs[n]] );
+			
+			if (fabs(distArray[xrefs[n]] - distArray[xrefs[v]]) > posThreshold) {
+				break;
+			}
+			
+			TriMesh::Vertex & v0 = mesh->vertexAt(xrefs[v]);
+			TriMesh::Vertex & v1 = mesh->vertexAt(xrefs[n]);
+			
+			const float dist = length(v0.pos - v1.pos);
+			
+			if (dist <= posThreshold) {
+				Snap(v0, v1, texThreshold, norThreshold);
+				snapCount++;
+			}
+		}
+	}
+
+	// @@ todo: debug, make sure that the distance between vertices is now >= threshold
+
+	nvDebug("---   %u vertices snapped\n", snapCount);
+
+	return snapCount;
+};
+
diff --git a/thirdparty/thekla_atlas/nvmesh/weld/Snap.h b/thirdparty/thekla_atlas/nvmesh/weld/Snap.h
new file mode 100644
index 0000000000..8e0566cda3
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/weld/Snap.h
@@ -0,0 +1,18 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#ifndef NV_MESH_SNAP_H
+#define NV_MESH_SNAP_H
+
+#include <nvmesh/nvmesh.h>
+#include <nvmath/nvmath.h>
+
+namespace nv
+{
+	class TriMesh;
+
+	NVMESH_API uint SnapVertices(TriMesh * mesh, float posThreshold=NV_EPSILON, float texThreshold=1.0f/1024, float norThreshold=NV_NORMAL_EPSILON);
+
+} // nv namespace
+
+
+#endif // NV_MESH_SNAP_H
diff --git a/thirdparty/thekla_atlas/nvmesh/weld/VertexWeld.cpp b/thirdparty/thekla_atlas/nvmesh/weld/VertexWeld.cpp
new file mode 100644
index 0000000000..2ba4dcae18
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/weld/VertexWeld.cpp
@@ -0,0 +1,205 @@
+// Copyright NVIDIA Corporation 2006 -- Ignacio Castano <icastano@nvidia.com>
+
+#include <nvmesh/TriMesh.h>
+#include <nvmesh/QuadTriMesh.h>
+
+#include <nvmesh/weld/VertexWeld.h>
+#include <nvmesh/weld/Weld.h>
+
+using namespace nv;
+
+// Weld trimesh vertices
+void nv::WeldVertices(TriMesh * mesh)
+{
+	nvDebug("--- Welding vertices.\n");
+	
+	nvCheck(mesh != NULL);
+
+	uint count = mesh->vertexCount();
+	Array<uint> xrefs;
+	Weld<TriMesh::Vertex> weld;
+	uint newCount = weld(mesh->vertices(), xrefs);
+	
+	nvDebug("---   %d vertices welded\n", count - newCount);
+	
+	
+	// Remap faces.
+	const uint faceCount = mesh->faceCount();
+	for(uint f = 0; f < faceCount; f++)
+	{
+		TriMesh::Face & face = mesh->faceAt(f);
+		face.v[0] = xrefs[face.v[0]];
+		face.v[1] = xrefs[face.v[1]];
+		face.v[2] = xrefs[face.v[2]];
+	}
+}
+
+
+// Weld trimesh vertices
+void nv::WeldVertices(QuadTriMesh * mesh)
+{
+	nvDebug("--- Welding vertices.\n");
+	
+	nvCheck(mesh != NULL);
+
+	uint  count = mesh->vertexCount();
+	Array<uint> xrefs;
+	Weld<TriMesh::Vertex> weld;
+	uint newCount = weld(mesh->vertices(), xrefs);
+	
+	nvDebug("---   %d vertices welded\n", count - newCount);
+	
+	// Remap faces.
+	const uint faceCount = mesh->faceCount();
+	for(uint f = 0; f < faceCount; f++)
+	{
+		QuadTriMesh::Face & face = mesh->faceAt(f);
+		face.v[0] = xrefs[face.v[0]];
+		face.v[1] = xrefs[face.v[1]];
+		face.v[2] = xrefs[face.v[2]];
+		
+		if (face.isQuadFace())
+		{
+			face.v[3] = xrefs[face.v[3]];
+		}
+	}
+}
+
+
+
+// OLD code
+
+#if 0
+
+namespace {
+
+struct VertexInfo {
+	uint id;			///< Original vertex id.
+	uint normal_face_group;
+	uint tangent_face_group;
+	uint material;
+	uint chart;
+};
+
+
+/// VertexInfo hash functor.
+struct VertexHash : public IHashFunctor<VertexInfo> {
+	VertexHash(PiMeshPtr m) : mesh(m) {
+		uint c = mesh->FindChannel(VS_POS);
+		piCheck(c != PI_NULL_INDEX);
+		channel = mesh->GetChannel(c);
+		piCheck(channel != NULL);
+	}
+
+	uint32 operator () (const VertexInfo & v) const {
+		return channel->data[v.id].GetHash();
+	}
+	
+private:
+	PiMeshPtr mesh;
+	PiMesh::Channel * channel;
+};
+
+
+/// VertexInfo comparator.
+struct VertexEqual : public IBinaryPredicate<VertexInfo> {
+	VertexEqual(PiMeshPtr m) : mesh(m) {}
+	
+	bool operator () (const VertexInfo & a, const VertexInfo & b) const {
+
+		bool equal = a.normal_face_group == b.normal_face_group && 
+			a.tangent_face_group == b.tangent_face_group &&
+			a.material == b.material && 
+			a.chart == b.chart;
+		
+		// Split vertex shared by different face types.
+		if( !equal ) {
+			return false;
+		}
+		
+		// They were the same vertex.
+		if( a.id == b.id ) {
+			return true;
+		}
+		
+		// Vertex equal if all the channels are equal.
+		return mesh->IsVertexEqual(a.id, b.id);
+	}
+
+private:	
+	PiMeshPtr mesh;
+};
+
+} // namespace
+
+
+/// Weld the vertices.
+void PiMeshVertexWeld::WeldVertices(const PiMeshSmoothGroup * mesh_smooth_group, 
+	const PiMeshMaterial * mesh_material, const PiMeshAtlas * mesh_atlas ) 
+{
+	piDebug( "--- Welding vertices:\n" );
+
+	piDebug( "---   Expand mesh vertices.\n" );
+	PiArray<VertexInfo> vertex_array;
+
+	const uint face_num = mesh->GetFaceNum();
+	const uint vertex_max = face_num * 3;
+	vertex_array.Resize( vertex_max );
+
+	for(uint i = 0; i < vertex_max; i++) {
+
+		uint f = i/3;
+	
+		const PiMesh::Face & face = mesh->GetFace(f);
+		vertex_array[i].id = face.v[i%3];
+
+		// Reset face attributes.
+		vertex_array[i].normal_face_group = PI_NULL_INDEX;
+		vertex_array[i].tangent_face_group = PI_NULL_INDEX;
+		vertex_array[i].material = PI_NULL_INDEX;
+		vertex_array[i].chart = PI_NULL_INDEX;
+		
+		// Set available attributes.
+		if( mesh_smooth_group != NULL ) {
+			if( mesh_smooth_group->HasNormalFaceGroups() ) {
+				vertex_array[i].normal_face_group = mesh_smooth_group->GetNormalFaceGroup( f );
+			}
+			if( mesh_smooth_group->HasTangentFaceGroups() ) {
+				vertex_array[i].tangent_face_group = mesh_smooth_group->GetTangentFaceGroup( f );
+			}
+		}
+		if( mesh_material != NULL ) {
+			vertex_array[i].material = mesh_material->GetFaceMaterial( f );
+		}
+		if( mesh_atlas != NULL && mesh_atlas->HasCharts() ) {
+			vertex_array[i].chart = mesh_atlas->GetFaceChart( f );
+		}
+	}
+	piDebug( "---   %d vertices.\n", vertex_max );
+
+	piDebug( "---   Collapse vertices.\n" );
+
+	uint * xrefs = new uint[vertex_max];
+	VertexHash hash(mesh);
+	VertexEqual equal(mesh);
+	const uint vertex_num = Weld( vertex_array, xrefs, hash, equal );
+	piCheck(vertex_num <= vertex_max);
+	piDebug( "---   %d vertices.\n", vertex_num );	
+	
+	// Remap face indices.
+	piDebug( "---   Remapping face indices.\n" );
+	mesh->RemapFaceIndices(vertex_max, xrefs);
+
+
+	// Overwrite xrefs to map new vertices to old vertices.
+	for(uint v = 0; v < vertex_num; v++) {
+		xrefs[v] = vertex_array[v].id;
+	}
+	
+	// Update vertex order.
+	mesh->ReorderVertices(vertex_num, xrefs);
+
+	delete [] xrefs;
+}
+
+#endif // 0
diff --git a/thirdparty/thekla_atlas/nvmesh/weld/VertexWeld.h b/thirdparty/thekla_atlas/nvmesh/weld/VertexWeld.h
new file mode 100644
index 0000000000..1dc2e4ba4d
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/weld/VertexWeld.h
@@ -0,0 +1,19 @@
+// Copyright NVIDIA Corporation 2006 -- Ignacio Castano <icastano@nvidia.com>
+
+#ifndef NV_MESH_VERTEXWELD_H
+#define NV_MESH_VERTEXWELD_H
+
+#include <nvmesh/nvmesh.h>
+
+namespace nv
+{
+	class TriMesh;
+	class QuadMesh;
+
+	NVMESH_API void WeldVertices(TriMesh * mesh);
+	NVMESH_API void WeldVertices(QuadTriMesh * mesh);
+
+} // nv namespace
+
+
+#endif // NV_MESH_VERTEXWELD_H
diff --git a/thirdparty/thekla_atlas/nvmesh/weld/Weld.h b/thirdparty/thekla_atlas/nvmesh/weld/Weld.h
new file mode 100644
index 0000000000..e615539461
--- /dev/null
+++ b/thirdparty/thekla_atlas/nvmesh/weld/Weld.h
@@ -0,0 +1,171 @@
+// This code is in the public domain -- castanyo@yahoo.es
+
+#ifndef NV_MESH_WELD_H
+#define NV_MESH_WELD_H
+
+#include "nvcore/Array.h"
+#include "nvcore/Hash.h"
+#include "nvcore/Utils.h" // nextPowerOfTwo
+
+#include <string.h> // for memset, memcmp, memcpy
+
+// Weld function to remove array duplicates in linear time using hashing.
+
+namespace nv
+{
+
+/// Generic welding routine. This function welds the elements of the array p
+/// and returns the cross references in the xrefs array. To compare the elements
+/// it uses the given hash and equal functors.
+/// 
+/// This code is based on the ideas of Ville Miettinen and Pierre Terdiman.
+template <class T, class H=Hash<T>, class E=Equal<T> >
+struct Weld
+{
+	// xrefs maps old elements to new elements
+	uint operator()(Array<T> & p, Array<uint> & xrefs)
+	{
+		const uint N = p.size();							// # of input vertices.
+		uint outputCount = 0;								// # of output vertices
+		uint hashSize = nextPowerOfTwo(N);					// size of the hash table
+		uint * hashTable = new uint[hashSize + N];			// hash table + linked list
+		uint * next = hashTable + hashSize;					// use bottom part as linked list
+
+		xrefs.resize(N);
+		memset( hashTable, NIL, hashSize*sizeof(uint) );	// init hash table (NIL = 0xFFFFFFFF so memset works)
+
+		H hash;
+		E equal;
+		for (uint i = 0; i < N; i++)
+		{
+			const T & e = p[i];
+			uint32 hashValue = hash(e) & (hashSize-1);
+			uint offset = hashTable[hashValue];
+
+			// traverse linked list
+			while( offset != NIL && !equal(p[offset], e) )
+			{
+				offset = next[offset];
+			}
+
+			xrefs[i] = offset;
+
+			// no match found - copy vertex & add to hash
+			if( offset == NIL )
+			{
+				// save xref
+				xrefs[i] = outputCount;
+
+				// copy element
+				p[outputCount] = e;
+
+				// link to hash table
+				next[outputCount] = hashTable[hashValue];
+
+				// update hash heads and increase output counter
+				hashTable[hashValue] = outputCount++;
+			}
+		}
+
+		// cleanup
+		delete [] hashTable;
+
+		p.resize(outputCount);
+		
+		// number of output vertices
+		return outputCount;
+	}
+};
+
+
+/// Reorder the given array accoding to the indices given in xrefs.
+template <class T>
+void reorderArray(Array<T> & array, const Array<uint> & xrefs)
+{
+	const uint count = xrefs.count();
+	Array<T> new_array;
+    new_array.resize(count);
+
+	for(uint i = 0; i < count; i++) {
+		new_array[i] = array[xrefs[i]];
+	}
+
+	swap(array, new_array);
+}
+
+/// Reverse the given array so that new indices point to old indices.
+inline void reverseXRefs(Array<uint> & xrefs, uint count)
+{
+	Array<uint> new_xrefs;
+    new_xrefs.resize(count);
+	
+	for(uint i = 0; i < xrefs.count(); i++) {
+		new_xrefs[xrefs[i]] = i;
+	}
+	
+	swap(xrefs, new_xrefs);
+}
+
+
+
+//
+struct WeldN
+{
+    uint vertexSize;
+
+    WeldN(uint n) : vertexSize(n) {}
+
+	// xrefs maps old elements to new elements
+	uint operator()(uint8 * ptr, uint N, Array<uint> & xrefs)
+	{
+		uint outputCount = 0;								// # of output vertices
+		uint hashSize = nextPowerOfTwo(N);					// size of the hash table
+		uint * hashTable = new uint[hashSize + N];			// hash table + linked list
+		uint * next = hashTable + hashSize;					// use bottom part as linked list
+
+		xrefs.resize(N);
+		memset( hashTable, NIL, hashSize*sizeof(uint) );	// init hash table (NIL = 0xFFFFFFFF so memset works)
+
+		for (uint i = 0; i < N; i++)
+		{
+			const uint8 * vertex = ptr + i * vertexSize;
+			uint32 hashValue = sdbmHash(vertex, vertexSize) & (hashSize-1);
+			uint offset = hashTable[hashValue];
+
+			// traverse linked list
+			while (offset != NIL && memcmp(ptr + offset * vertexSize, vertex, vertexSize) != 0)
+			{
+				offset = next[offset];
+			}
+
+			xrefs[i] = offset;
+
+			// no match found - copy vertex & add to hash
+			if (offset == NIL)
+			{
+				// save xref
+				xrefs[i] = outputCount;
+
+				// copy element
+                memcpy(ptr + outputCount * vertexSize, vertex, vertexSize);
+
+				// link to hash table
+				next[outputCount] = hashTable[hashValue];
+
+				// update hash heads and increase output counter
+				hashTable[hashValue] = outputCount++;
+			}
+		}
+
+		// cleanup
+		delete [] hashTable;
+
+		// number of output vertices
+		return outputCount;
+	}
+};
+
+
+} // nv namespace
+
+#endif // NV_MESH_WELD_H