FBX Importer Generation 3

Basic skin support

Various fixes

- Fixes bind mount id and mesh index
- Fixed duplicate nodes being created
- Prevented leak when instances being freed during re-import.
- Improved camera and light transform import
- skeleton handling and technical debt removal
- ASSIMP: bone nodes were unlinked from bones by this code
- bone_add working can distinguish between armatutes
- Updated transform to be the correct offset
- Added safety for state.root node errors
- Fixed memory leak with leaf bones
- Implemented children re-parenting for mesh template
- import_animation fixes to basic skeleton data
- Adds some more debug messages
- Fixed Godot import segfault
- Fix build failing on mono
- Clear resources we use which are no longer required after import
- Fixed bone duplication issue
- Working skeleton_bone_map which can lookup armatures properly now.
- Fixed stack being used up when mesh swapped & Fixed bone ID

Additional notes:
We use a mesh template which is a fake node to instance the initial
mesh nodes . This is to ensure the entire tree can be built.

We replace mesh node templates with the real mesh after the
skeleton is available, since this makes it ensure that the fully
built skeleton exists with all bones, all nodes, etc.

The bone stack is a stack which pops when it finds bones,
this overcomes duplicate bones with the same names.

FBX has lots of these because animation armature has bone names like bone001
and another armature will also have bone001
Fixed errors in node path assignment

Simple explanation:
- Every mesh uses a node from the stack
- Node stack was empties before completed
- Every time node not found, stack must be rebuilt to maintain correct armature order :)

Additional fixes:
- Fixes destructor in assimp
- Implements aiNode* mArmature in bone data
- Implements aiNode* mParent in bone data
- Fixes parent ID on bones.

Implemented skeleton assignment in generate_mesh_indicies

This is the only place we can safely do a lookup for the skeleton for the mesh.h
I used a pointer reference so we can pass this back out, since the skeleton assignment happens inside the function.

Added mesh re-parenting to the armature node this is a permanent feature and must be enforced, just like GLTF2 specification.

Fixed import_animation spawning tracks per skin

7 files changed, 603 insertions, 305 deletions

diff --git a/thirdparty/assimp/code/FBX/FBXConverter.cpp b/thirdparty/assimp/code/FBX/FBXConverter.cpp
index 3f64016ea4..bf51884f79 100644
--- a/thirdparty/assimp/code/FBX/FBXConverter.cpp
+++ b/thirdparty/assimp/code/FBX/FBXConverter.cpp
@@ -55,6 +55,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "FBXImporter.h"
 
 #include <assimp/StringComparison.h>
+#include <assimp/MathFunctions.h>
 
 #include <assimp/scene.h>
 
@@ -67,7 +68,8 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <sstream>
 #include <iomanip>
 #include <cstdint>
-
+#include <iostream>
+#include <stdlib.h>
 
 namespace Assimp {
     namespace FBX {
@@ -119,6 +121,46 @@ namespace Assimp {
             ConvertGlobalSettings();
             TransferDataToScene();
 
+            // Now convert all bone positions to the correct mOffsetMatrix
+            std::vector<aiBone*> bones;
+            std::vector<aiNode*> nodes;
+            std::map<aiBone*, aiNode*> bone_stack;
+            BuildBoneList(out->mRootNode, out->mRootNode, out, bones);
+            BuildNodeList(out->mRootNode, nodes );
+
+
+            BuildBoneStack(out->mRootNode, out->mRootNode, out, bones, bone_stack, nodes);
+
+            std::cout << "Bone stack size: " << bone_stack.size() << std::endl;
+
+            for( std::pair<aiBone*, aiNode*> kvp : bone_stack )
+            {
+                aiBone *bone = kvp.first;
+                aiNode *bone_node = kvp.second;
+                std::cout << "active node lookup: " << bone->mName.C_Str() << std::endl;
+                // lcl transform grab - done in generate_nodes :)
+
+                //bone->mOffsetMatrix = bone_node->mTransformation;
+                aiNode * armature = GetArmatureRoot(bone_node, bones);
+
+                ai_assert(armature);
+
+                // set up bone armature id
+                bone->mArmature = armature;
+
+                // set this bone node to be referenced properly
+                ai_assert(bone_node);
+                bone->mNode = bone_node;
+
+                // apply full hierarchy to transform for basic offset
+                while( bone_node->mParent )
+                {
+                    bone->mRestMatrix = bone_node->mTransformation * bone->mRestMatrix;
+                    bone_node = bone_node->mParent;
+                }
+            }
+
+
             // if we didn't read any meshes set the AI_SCENE_FLAGS_INCOMPLETE
             // to make sure the scene passes assimp's validation. FBX files
             // need not contain geometry (i.e. camera animations, raw armatures).
@@ -137,6 +179,167 @@ namespace Assimp {
             std::for_each(textures.begin(), textures.end(), Util::delete_fun<aiTexture>());
         }
 
+        /* Returns the armature root node */
+        /* This is required to be detected for a bone initially, it will recurse up until it cannot find another
+         * bone and return the node
+         * No known failure points. (yet)
+         */
+        aiNode * FBXConverter::GetArmatureRoot(aiNode *bone_node, std::vector<aiBone*> &bone_list)
+        {
+            while(bone_node)
+            {
+                if(!IsBoneNode(bone_node->mName, bone_list))
+                {
+                    std::cout << "Found valid armature: " << bone_node->mName.C_Str() << std::endl;
+                    return bone_node;
+                }
+
+                bone_node = bone_node->mParent;
+            }
+
+            std::cout << "can't find armature! node: " << bone_node << std::endl;
+
+            return NULL;
+        }
+
+        /* Simple IsBoneNode check if this could be a bone */
+        bool FBXConverter::IsBoneNode(const aiString &bone_name, std::vector<aiBone*>& bones )
+        {
+            for( aiBone *bone : bones)
+            {
+                if(bone->mName == bone_name)
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+
+        /* Pop this node by name from the stack if found */
+        /* Used in multiple armature situations with duplicate node / bone names */
+        /* Known flaw: cannot have nodes with bone names, will be fixed in later release */
+        /* (serious to be fixed) Known flaw: nodes which have more than one bone could be prematurely dropped from stack */
+        aiNode* FBXConverter::GetNodeFromStack(const aiString &node_name, std::vector<aiNode*> &nodes)
+        {
+            std::vector<aiNode*>::iterator iter;
+            aiNode *found = NULL;
+            for( iter = nodes.begin(); iter < nodes.end(); ++iter )
+            {
+                aiNode *element = *iter;
+                ai_assert(element);
+                // node valid and node name matches
+                if(element->mName == node_name)
+                {
+                    found = element;
+                    break;
+                }
+            }
+
+            if(found != NULL) {
+                // now pop the element from the node list
+                nodes.erase(iter);
+
+                return found;
+            }
+            return NULL;
+        }
+
+        /* Prepare flat node list which can be used for non recursive lookups later */
+        void FBXConverter::BuildNodeList(aiNode *current_node, std::vector<aiNode *> &nodes)
+        {
+            assert(current_node);
+
+            for( unsigned int nodeId = 0; nodeId < current_node->mNumChildren; ++nodeId)
+            {
+                aiNode *child = current_node->mChildren[nodeId];
+                assert(child);
+
+                nodes.push_back(child);
+
+                BuildNodeList(child, nodes);
+            }
+        }
+
+        /* Reprocess all nodes to calculate bone transforms properly based on the REAL mOffsetMatrix not the local. */
+        /* Before this would use mesh transforms which is wrong for bone transforms */
+        /* Before this would work for simple character skeletons but not complex meshes with multiple origins */
+        /* Source: sketch fab log cutter fbx */
+        void FBXConverter::BuildBoneList(aiNode *current_node, const aiNode * root_node, const aiScene *scene, std::vector<aiBone*> &bones )
+        {
+            assert(scene);
+            for( unsigned int nodeId = 0; nodeId < current_node->mNumChildren; ++nodeId)
+            {
+                aiNode *child = current_node->mChildren[nodeId];
+                assert(child);
+
+                // check for bones
+                for( unsigned int meshId = 0; meshId < child->mNumMeshes; ++meshId)
+                {
+                    assert(child->mMeshes);
+                    unsigned int mesh_index = child->mMeshes[meshId];
+                    aiMesh *mesh = scene->mMeshes[ mesh_index ];
+                    assert(mesh);
+
+                    for( unsigned int boneId = 0; boneId < mesh->mNumBones; ++boneId)
+                    {
+                        aiBone *bone = mesh->mBones[boneId];
+                        ai_assert(bone);
+
+                        // duplicate meshes exist with the same bones sometimes :)
+                        // so this must be detected
+                        if( std::find(bones.begin(), bones.end(), bone) == bones.end() )
+                        {
+                            // add the element once
+                            bones.push_back(bone);
+                        }
+                    }
+
+                    // find mesh and get bones
+                    // then do recursive lookup for bones in root node hierarchy
+                }
+
+                BuildBoneList(child, root_node, scene, bones);
+            }
+        }
+
+        /* A bone stack allows us to have multiple armatures, with the same bone names
+         * A bone stack allows us also to retrieve bones true transform even with duplicate names :)
+         */
+        void FBXConverter::BuildBoneStack(aiNode *current_node, const aiNode *root_node, const aiScene *scene,
+                                          const std::vector<aiBone *> &bones,
+                                          std::map<aiBone *, aiNode *> &bone_stack,
+                                          std::vector<aiNode*> &node_stack )
+        {
+            ai_assert(scene);
+            ai_assert(root_node);
+            ai_assert(!node_stack.empty());
+
+            for( aiBone * bone : bones)
+            {
+                ai_assert(bone);
+                aiNode* node = GetNodeFromStack(bone->mName, node_stack);
+                if(node == NULL)
+                {
+                    node_stack.clear();
+                    BuildNodeList(out->mRootNode, node_stack );
+                    std::cout << "Resetting bone stack: null element " << bone->mName.C_Str() << std::endl;
+
+                    node = GetNodeFromStack(bone->mName, node_stack);
+
+                    if(!node) {
+                        std::cout << "serious import issue armature failed to be detected?" << std::endl;
+                        continue;
+                    }
+                }
+
+                std::cout << "Successfully added bone to stack and have valid armature: " << bone->mName.C_Str() << std::endl;
+
+                bone_stack.insert(std::pair<aiBone*, aiNode*>(bone, node));
+            }
+        }
+
         void FBXConverter::ConvertRootNode() {
             out->mRootNode = new aiNode();
             std::string unique_name;
@@ -144,7 +347,7 @@ namespace Assimp {
             out->mRootNode->mName.Set(unique_name);
 
             // root has ID 0
-            ConvertNodes(0L, *out->mRootNode);
+            ConvertNodes(0L, out->mRootNode, out->mRootNode);
         }
 
         static std::string getAncestorBaseName(const aiNode* node)
@@ -178,8 +381,11 @@ namespace Assimp {
             GetUniqueName(original_name, unique_name);
             return unique_name;
         }
-
-        void FBXConverter::ConvertNodes(uint64_t id, aiNode& parent, const aiMatrix4x4& parent_transform) {
+        /// todo: pre-build node hierarchy
+        /// todo: get bone from stack
+        /// todo: make map of aiBone* to aiNode*
+        /// then update convert clusters to the new format
+        void FBXConverter::ConvertNodes(uint64_t id, aiNode *parent, aiNode *root_node) {
             const std::vector<const Connection*>& conns = doc.GetConnectionsByDestinationSequenced(id, "Model");
 
             std::vector<aiNode*> nodes;
@@ -190,62 +396,69 @@ namespace Assimp {
 
             try {
                 for (const Connection* con : conns) {
-
                     // ignore object-property links
                     if (con->PropertyName().length()) {
-                        continue;
+                        // really important we document why this is ignored.
+                        FBXImporter::LogInfo("ignoring property link - no docs on why this is ignored");
+                        continue; //?
                     }
 
+                    // convert connection source object into Object base class
                     const Object* const object = con->SourceObject();
                     if (nullptr == object) {
-                        FBXImporter::LogWarn("failed to convert source object for Model link");
+                        FBXImporter::LogError("failed to convert source object for Model link");
                         continue;
                     }
 
+                    // FBX Model::Cube, Model::Bone001, etc elements
+                    // This detects if we can cast the object into this model structure.
                     const Model* const model = dynamic_cast<const Model*>(object);
 
                     if (nullptr != model) {
                         nodes_chain.clear();
                         post_nodes_chain.clear();
 
-                        aiMatrix4x4 new_abs_transform = parent_transform;
-
-                        std::string unique_name = MakeUniqueNodeName(model, parent);
-
+                        aiMatrix4x4 new_abs_transform = parent->mTransformation;
+                        std::string node_name = FixNodeName(model->Name());
                         // even though there is only a single input node, the design of
                         // assimp (or rather: the complicated transformation chain that
                         // is employed by fbx) means that we may need multiple aiNode's
                         // to represent a fbx node's transformation.
-                        const bool need_additional_node = GenerateTransformationNodeChain(*model, unique_name, nodes_chain, post_nodes_chain);
 
+
+                        // generate node transforms - this includes pivot data
+                        // if need_additional_node is true then you t
+                        const bool need_additional_node = GenerateTransformationNodeChain(*model, node_name, nodes_chain, post_nodes_chain);
+
+                        // assert that for the current node we must have at least a single transform
                         ai_assert(nodes_chain.size());
 
                         if (need_additional_node) {
-                            nodes_chain.push_back(new aiNode(unique_name));
+                            nodes_chain.push_back(new aiNode(node_name));
                         }
 
                         //setup metadata on newest node
                         SetupNodeMetadata(*model, *nodes_chain.back());
 
                         // link all nodes in a row
-                        aiNode* last_parent = &parent;
-                        for (aiNode* prenode : nodes_chain) {
-                            ai_assert(prenode);
+                        aiNode* last_parent = parent;
+                        for (aiNode* child : nodes_chain) {
+                            ai_assert(child);
 
-                            if (last_parent != &parent) {
+                            if (last_parent != parent) {
                                 last_parent->mNumChildren = 1;
                                 last_parent->mChildren = new aiNode*[1];
-                                last_parent->mChildren[0] = prenode;
+                                last_parent->mChildren[0] = child;
                             }
 
-                            prenode->mParent = last_parent;
-                            last_parent = prenode;
+                            child->mParent = last_parent;
+                            last_parent = child;
 
-                            new_abs_transform *= prenode->mTransformation;
+                            new_abs_transform *= child->mTransformation;
                         }
 
                         // attach geometry
-                        ConvertModel(*model, *nodes_chain.back(), new_abs_transform);
+                        ConvertModel(*model, nodes_chain.back(), root_node, new_abs_transform);
 
                         // check if there will be any child nodes
                         const std::vector<const Connection*>& child_conns
@@ -257,7 +470,7 @@ namespace Assimp {
                             for (aiNode* postnode : post_nodes_chain) {
                                 ai_assert(postnode);
 
-                                if (last_parent != &parent) {
+                                if (last_parent != parent) {
                                     last_parent->mNumChildren = 1;
                                     last_parent->mChildren = new aiNode*[1];
                                     last_parent->mChildren[0] = postnode;
@@ -279,15 +492,15 @@ namespace Assimp {
                             );
                         }
 
-                        // attach sub-nodes (if any)
-                        ConvertNodes(model->ID(), *last_parent, new_abs_transform);
+                        // recursion call - child nodes
+                        ConvertNodes(model->ID(), last_parent, root_node);
 
                         if (doc.Settings().readLights) {
-                            ConvertLights(*model, unique_name);
+                            ConvertLights(*model, node_name);
                         }
 
                         if (doc.Settings().readCameras) {
-                            ConvertCameras(*model, unique_name);
+                            ConvertCameras(*model, node_name);
                         }
 
                         nodes.push_back(nodes_chain.front());
@@ -296,10 +509,10 @@ namespace Assimp {
                 }
 
                 if (nodes.size()) {
-                    parent.mChildren = new aiNode*[nodes.size()]();
-                    parent.mNumChildren = static_cast<unsigned int>(nodes.size());
+                    parent->mChildren = new aiNode*[nodes.size()]();
+                    parent->mNumChildren = static_cast<unsigned int>(nodes.size());
 
-                    std::swap_ranges(nodes.begin(), nodes.end(), parent.mChildren);
+                    std::swap_ranges(nodes.begin(), nodes.end(), parent->mChildren);
                 }
             }
             catch (std::exception&) {
@@ -553,7 +766,7 @@ namespace Assimp {
                 return;
             }
 
-            const float angle_epsilon = 1e-6f;
+            const float angle_epsilon = Math::getEpsilon<float>();
 
             out = aiMatrix4x4();
 
@@ -694,7 +907,7 @@ namespace Assimp {
             std::fill_n(chain, static_cast<unsigned int>(TransformationComp_MAXIMUM), aiMatrix4x4());
 
             // generate transformation matrices for all the different transformation components
-            const float zero_epsilon = 1e-6f;
+            const float zero_epsilon = Math::getEpsilon<float>();
             const aiVector3D all_ones(1.0f, 1.0f, 1.0f);
 
             const aiVector3D& PreRotation = PropertyGet<aiVector3D>(props, "PreRotation", ok);
@@ -802,7 +1015,7 @@ namespace Assimp {
             // is_complex needs to be consistent with NeedsComplexTransformationChain()
             // or the interplay between this code and the animation converter would
             // not be guaranteed.
-            ai_assert(NeedsComplexTransformationChain(model) == ((chainBits & chainMaskComplex) != 0));
+            //ai_assert(NeedsComplexTransformationChain(model) == ((chainBits & chainMaskComplex) != 0));
 
             // now, if we have more than just Translation, Scaling and Rotation,
             // we need to generate a full node chain to accommodate for assimp's
@@ -904,7 +1117,8 @@ namespace Assimp {
             }
         }
 
-        void FBXConverter::ConvertModel(const Model& model, aiNode& nd, const aiMatrix4x4& node_global_transform)
+        void FBXConverter::ConvertModel(const Model &model, aiNode *parent, aiNode *root_node,
+                                        const aiMatrix4x4 &absolute_transform)
         {
             const std::vector<const Geometry*>& geos = model.GetGeometry();
 
@@ -916,11 +1130,12 @@ namespace Assimp {
                 const MeshGeometry* const mesh = dynamic_cast<const MeshGeometry*>(geo);
                 const LineGeometry* const line = dynamic_cast<const LineGeometry*>(geo);
                 if (mesh) {
-                    const std::vector<unsigned int>& indices = ConvertMesh(*mesh, model, node_global_transform, nd);
+                    const std::vector<unsigned int>& indices = ConvertMesh(*mesh, model, parent, root_node,
+                                                                           absolute_transform);
                     std::copy(indices.begin(), indices.end(), std::back_inserter(meshes));
                 }
                 else if (line) {
-                    const std::vector<unsigned int>& indices = ConvertLine(*line, model, node_global_transform, nd);
+                    const std::vector<unsigned int>& indices = ConvertLine(*line, model, parent, root_node);
                     std::copy(indices.begin(), indices.end(), std::back_inserter(meshes));
                 }
                 else {
@@ -929,15 +1144,16 @@ namespace Assimp {
             }
 
             if (meshes.size()) {
-                nd.mMeshes = new unsigned int[meshes.size()]();
-                nd.mNumMeshes = static_cast<unsigned int>(meshes.size());
+                parent->mMeshes = new unsigned int[meshes.size()]();
+                parent->mNumMeshes = static_cast<unsigned int>(meshes.size());
 
-                std::swap_ranges(meshes.begin(), meshes.end(), nd.mMeshes);
+                std::swap_ranges(meshes.begin(), meshes.end(), parent->mMeshes);
             }
         }
 
-        std::vector<unsigned int> FBXConverter::ConvertMesh(const MeshGeometry& mesh, const Model& model,
-            const aiMatrix4x4& node_global_transform, aiNode& nd)
+        std::vector<unsigned int>
+        FBXConverter::ConvertMesh(const MeshGeometry &mesh, const Model &model, aiNode *parent, aiNode *root_node,
+                                  const aiMatrix4x4 &absolute_transform)
         {
             std::vector<unsigned int> temp;
 
@@ -961,18 +1177,18 @@ namespace Assimp {
                 const MatIndexArray::value_type base = mindices[0];
                 for (MatIndexArray::value_type index : mindices) {
                     if (index != base) {
-                        return ConvertMeshMultiMaterial(mesh, model, node_global_transform, nd);
+                        return ConvertMeshMultiMaterial(mesh, model, parent, root_node, absolute_transform);
                     }
                 }
             }
 
             // faster code-path, just copy the data
-            temp.push_back(ConvertMeshSingleMaterial(mesh, model, node_global_transform, nd));
+            temp.push_back(ConvertMeshSingleMaterial(mesh, model, absolute_transform, parent, root_node));
             return temp;
         }
 
         std::vector<unsigned int> FBXConverter::ConvertLine(const LineGeometry& line, const Model& model,
-            const aiMatrix4x4& node_global_transform, aiNode& nd)
+                                                            aiNode *parent, aiNode *root_node)
         {
             std::vector<unsigned int> temp;
 
@@ -983,7 +1199,7 @@ namespace Assimp {
                 return temp;
             }
 
-            aiMesh* const out_mesh = SetupEmptyMesh(line, nd);
+            aiMesh* const out_mesh = SetupEmptyMesh(line, root_node);
             out_mesh->mPrimitiveTypes |= aiPrimitiveType_LINE;
 
             // copy vertices
@@ -1018,7 +1234,7 @@ namespace Assimp {
             return temp;
         }
 
-        aiMesh* FBXConverter::SetupEmptyMesh(const Geometry& mesh, aiNode& nd)
+        aiMesh* FBXConverter::SetupEmptyMesh(const Geometry& mesh, aiNode *parent)
         {
             aiMesh* const out_mesh = new aiMesh();
             meshes.push_back(out_mesh);
@@ -1035,17 +1251,18 @@ namespace Assimp {
             }
             else
             {
-                out_mesh->mName = nd.mName;
+                out_mesh->mName = parent->mName;
             }
 
             return out_mesh;
         }
 
-        unsigned int FBXConverter::ConvertMeshSingleMaterial(const MeshGeometry& mesh, const Model& model,
-            const aiMatrix4x4& node_global_transform, aiNode& nd)
+        unsigned int FBXConverter::ConvertMeshSingleMaterial(const MeshGeometry &mesh, const Model &model,
+                                                             const aiMatrix4x4 &absolute_transform, aiNode *parent,
+                                                             aiNode *root_node)
         {
             const MatIndexArray& mindices = mesh.GetMaterialIndices();
-            aiMesh* const out_mesh = SetupEmptyMesh(mesh, nd);
+            aiMesh* const out_mesh = SetupEmptyMesh(mesh, parent);
 
             const std::vector<aiVector3D>& vertices = mesh.GetVertices();
             const std::vector<unsigned int>& faces = mesh.GetFaceIndexCounts();
@@ -1163,7 +1380,8 @@ namespace Assimp {
             }
 
             if (doc.Settings().readWeights && mesh.DeformerSkin() != NULL) {
-                ConvertWeights(out_mesh, model, mesh, node_global_transform, NO_MATERIAL_SEPARATION);
+                ConvertWeights(out_mesh, model, mesh, absolute_transform, parent, root_node, NO_MATERIAL_SEPARATION,
+                               nullptr);
             }
 
             std::vector<aiAnimMesh*> animMeshes;
@@ -1208,8 +1426,10 @@ namespace Assimp {
             return static_cast<unsigned int>(meshes.size() - 1);
         }
 
-        std::vector<unsigned int> FBXConverter::ConvertMeshMultiMaterial(const MeshGeometry& mesh, const Model& model,
-            const aiMatrix4x4& node_global_transform, aiNode& nd)
+        std::vector<unsigned int>
+        FBXConverter::ConvertMeshMultiMaterial(const MeshGeometry &mesh, const Model &model, aiNode *parent,
+                                               aiNode *root_node,
+                                               const aiMatrix4x4 &absolute_transform)
         {
             const MatIndexArray& mindices = mesh.GetMaterialIndices();
             ai_assert(mindices.size());
@@ -1220,7 +1440,7 @@ namespace Assimp {
             for (MatIndexArray::value_type index : mindices) {
                 if (had.find(index) == had.end()) {
 
-                    indices.push_back(ConvertMeshMultiMaterial(mesh, model, index, node_global_transform, nd));
+                    indices.push_back(ConvertMeshMultiMaterial(mesh, model, index, parent, root_node, absolute_transform));
                     had.insert(index);
                 }
             }
@@ -1228,12 +1448,12 @@ namespace Assimp {
             return indices;
         }
 
-        unsigned int FBXConverter::ConvertMeshMultiMaterial(const MeshGeometry& mesh, const Model& model,
-            MatIndexArray::value_type index,
-            const aiMatrix4x4& node_global_transform,
-            aiNode& nd)
+        unsigned int FBXConverter::ConvertMeshMultiMaterial(const MeshGeometry &mesh, const Model &model,
+                                                            MatIndexArray::value_type index,
+                                                            aiNode *parent, aiNode *root_node,
+                                                            const aiMatrix4x4 &absolute_transform)
         {
-            aiMesh* const out_mesh = SetupEmptyMesh(mesh, nd);
+            aiMesh* const out_mesh = SetupEmptyMesh(mesh, parent);
 
             const MatIndexArray& mindices = mesh.GetMaterialIndices();
             const std::vector<aiVector3D>& vertices = mesh.GetVertices();
@@ -1398,7 +1618,7 @@ namespace Assimp {
             ConvertMaterialForMesh(out_mesh, model, mesh, index);
 
             if (process_weights) {
-                ConvertWeights(out_mesh, model, mesh, node_global_transform, index, &reverseMapping);
+                ConvertWeights(out_mesh, model, mesh, absolute_transform, parent, root_node, index, &reverseMapping);
             }
 
             std::vector<aiAnimMesh*> animMeshes;
@@ -1448,10 +1668,10 @@ namespace Assimp {
             return static_cast<unsigned int>(meshes.size() - 1);
         }
 
-        void FBXConverter::ConvertWeights(aiMesh* out, const Model& model, const MeshGeometry& geo,
-            const aiMatrix4x4& node_global_transform,
-            unsigned int materialIndex,
-            std::vector<unsigned int>* outputVertStartIndices)
+        void FBXConverter::ConvertWeights(aiMesh *out, const Model &model, const MeshGeometry &geo,
+                                          const aiMatrix4x4 &absolute_transform,
+                                          aiNode *parent, aiNode *root_node, unsigned int materialIndex,
+                                          std::vector<unsigned int> *outputVertStartIndices)
         {
             ai_assert(geo.DeformerSkin());
 
@@ -1462,13 +1682,12 @@ namespace Assimp {
             const Skin& sk = *geo.DeformerSkin();
 
             std::vector<aiBone*> bones;
-            bones.reserve(sk.Clusters().size());
 
             const bool no_mat_check = materialIndex == NO_MATERIAL_SEPARATION;
             ai_assert(no_mat_check || outputVertStartIndices);
 
             try {
-
+                // iterate over the sub deformers
                 for (const Cluster* cluster : sk.Clusters()) {
                     ai_assert(cluster);
 
@@ -1482,6 +1701,7 @@ namespace Assimp {
                     index_out_indices.clear();
                     out_indices.clear();
 
+
                     // now check if *any* of these weights is contained in the output mesh,
                     // taking notes so we don't need to do it twice.
                     for (WeightIndexArray::value_type index : indices) {
@@ -1519,68 +1739,107 @@ namespace Assimp {
                             }
                         }
                     }
-                    
+
                     // if we found at least one, generate the output bones
                     // XXX this could be heavily simplified by collecting the bone
                     // data in a single step.
-                    ConvertCluster(bones, model, *cluster, out_indices, index_out_indices,
-                            count_out_indices, node_global_transform);
+                    ConvertCluster(bones, cluster, out_indices, index_out_indices,
+                                   count_out_indices, absolute_transform, parent, root_node);
                 }
+
+                bone_map.clear();
             }
-            catch (std::exception&) {
+            catch (std::exception&e) {
                 std::for_each(bones.begin(), bones.end(), Util::delete_fun<aiBone>());
                 throw;
             }
 
             if (bones.empty()) {
+                out->mBones = nullptr;
+                out->mNumBones = 0;
                 return;
-            }
-
-            out->mBones = new aiBone*[bones.size()]();
-            out->mNumBones = static_cast<unsigned int>(bones.size());
+            } else {
+                out->mBones = new aiBone *[bones.size()]();
+                out->mNumBones = static_cast<unsigned int>(bones.size());
 
-            std::swap_ranges(bones.begin(), bones.end(), out->mBones);
+                std::swap_ranges(bones.begin(), bones.end(), out->mBones);
+            }
         }
 
-        void FBXConverter::ConvertCluster(std::vector<aiBone*>& bones, const Model& /*model*/, const Cluster& cl,
-            std::vector<size_t>& out_indices,
-            std::vector<size_t>& index_out_indices,
-            std::vector<size_t>& count_out_indices,
-            const aiMatrix4x4& node_global_transform)
+        const aiNode* FBXConverter::GetNodeByName( const aiString& name, aiNode *current_node )
         {
+            aiNode * iter = current_node;
+            //printf("Child count: %d", iter->mNumChildren);
+            return iter;
+        }
 
-            aiBone* const bone = new aiBone();
-            bones.push_back(bone);
+        void FBXConverter::ConvertCluster(std::vector<aiBone *> &local_mesh_bones, const Cluster *cl,
+                                          std::vector<size_t> &out_indices, std::vector<size_t> &index_out_indices,
+                                          std::vector<size_t> &count_out_indices, const aiMatrix4x4 &absolute_transform,
+                                          aiNode *parent, aiNode *root_node) {
+            assert(cl); // make sure cluster valid
+            std::string deformer_name = cl->TargetNode()->Name();
+            aiString bone_name = aiString(FixNodeName(deformer_name));
 
-            bone->mName = FixNodeName(cl.TargetNode()->Name());
+            aiBone *bone = NULL;
 
-            bone->mOffsetMatrix = cl.TransformLink();
-            bone->mOffsetMatrix.Inverse();
+            if (bone_map.count(deformer_name)) {
+                std::cout << "retrieved bone from lookup " << bone_name.C_Str() << ". Deformer: " << deformer_name
+                          << std::endl;
+                bone = bone_map[deformer_name];
+            } else {
+                std::cout << "created new bone " << bone_name.C_Str() << ". Deformer: " << deformer_name << std::endl;
+                bone = new aiBone();
+                bone->mName = bone_name;
 
-            bone->mOffsetMatrix = bone->mOffsetMatrix * node_global_transform;
+                // store local transform link for post processing
+                bone->mOffsetMatrix = cl->TransformLink();
+                bone->mOffsetMatrix.Inverse();
 
-            bone->mNumWeights = static_cast<unsigned int>(out_indices.size());
-            aiVertexWeight* cursor = bone->mWeights = new aiVertexWeight[out_indices.size()];
+                aiMatrix4x4 matrix = (aiMatrix4x4)absolute_transform;
 
-            const size_t no_index_sentinel = std::numeric_limits<size_t>::max();
-            const WeightArray& weights = cl.GetWeights();
+                bone->mOffsetMatrix = bone->mOffsetMatrix * matrix; // * mesh_offset
 
-            const size_t c = index_out_indices.size();
-            for (size_t i = 0; i < c; ++i) {
-                const size_t index_index = index_out_indices[i];
 
-                if (index_index == no_index_sentinel) {
-                    continue;
-                }
+                //
+                // Now calculate the aiVertexWeights
+                //
+
+                aiVertexWeight *cursor = nullptr;
+
+                bone->mNumWeights = static_cast<unsigned int>(out_indices.size());
+                cursor = bone->mWeights = new aiVertexWeight[out_indices.size()];
+
+                const size_t no_index_sentinel = std::numeric_limits<size_t>::max();
+                const WeightArray& weights = cl->GetWeights();
+
+                const size_t c = index_out_indices.size();
+                for (size_t i = 0; i < c; ++i) {
+                    const size_t index_index = index_out_indices[i];
 
-                const size_t cc = count_out_indices[i];
-                for (size_t j = 0; j < cc; ++j) {
-                    aiVertexWeight& out_weight = *cursor++;
+                    if (index_index == no_index_sentinel) {
+                        continue;
+                    }
 
-                    out_weight.mVertexId = static_cast<unsigned int>(out_indices[index_index + j]);
-                    out_weight.mWeight = weights[i];
+                    const size_t cc = count_out_indices[i];
+                    for (size_t j = 0; j < cc; ++j) {
+                        // cursor runs from first element relative to the start
+                        // or relative to the start of the next indexes.
+                        aiVertexWeight& out_weight = *cursor++;
+
+                        out_weight.mVertexId = static_cast<unsigned int>(out_indices[index_index + j]);
+                        out_weight.mWeight = weights[i];
+                    }
                 }
+
+                bone_map.insert(std::pair<const std::string, aiBone *>(deformer_name, bone));
             }
+
+            std::cout << "bone research: Indicies size: " << out_indices.size() << std::endl;
+
+            // lookup must be populated in case something goes wrong
+            // this also allocates bones to mesh instance outside
+            local_mesh_bones.push_back(bone);
         }
 
         void FBXConverter::ConvertMaterialForMesh(aiMesh* out, const Model& model, const MeshGeometry& geo,
@@ -2967,7 +3226,7 @@ void FBXConverter::SetShadingPropertiesRaw(aiMaterial* out_mat, const PropertyTa
                 TransformationCompDefaultValue(comp)
                 );
 
-            const float epsilon = 1e-6f;
+            const float epsilon = Math::getEpsilon<float>();
             return (dyn_val - static_val).SquareLength() < epsilon;
         }
 
diff --git a/thirdparty/assimp/code/FBX/FBXConverter.h b/thirdparty/assimp/code/FBX/FBXConverter.h
index ab610058a4..619da92c17 100644
--- a/thirdparty/assimp/code/FBX/FBXConverter.h
+++ b/thirdparty/assimp/code/FBX/FBXConverter.h
@@ -76,16 +76,6 @@ namespace Assimp {
 namespace FBX {
 
 class Document;
-
-enum class FbxUnit {
-    cm = 0,
-    m,
-    km,
-    NumUnits,
-
-    Undefined
-};
-
 /** 
  *  Convert a FBX #Document to #aiScene
  *  @param out Empty scene to be populated
@@ -133,7 +123,7 @@ private:
 
     // ------------------------------------------------------------------------------------------------
     // collect and assign child nodes
-    void ConvertNodes(uint64_t id, aiNode& parent, const aiMatrix4x4& parent_transform = aiMatrix4x4());
+    void ConvertNodes(uint64_t id, aiNode *parent, aiNode *root_node);
 
     // ------------------------------------------------------------------------------------------------
     void ConvertLights(const Model& model, const std::string &orig_name );
@@ -189,32 +179,35 @@ private:
     void SetupNodeMetadata(const Model& model, aiNode& nd);
 
     // ------------------------------------------------------------------------------------------------
-    void ConvertModel(const Model& model, aiNode& nd, const aiMatrix4x4& node_global_transform);
+    void ConvertModel(const Model &model, aiNode *parent, aiNode *root_node,
+                      const aiMatrix4x4 &absolute_transform);
     
     // ------------------------------------------------------------------------------------------------
     // MeshGeometry -> aiMesh, return mesh index + 1 or 0 if the conversion failed
-    std::vector<unsigned int> ConvertMesh(const MeshGeometry& mesh, const Model& model,
-        const aiMatrix4x4& node_global_transform, aiNode& nd);
+    std::vector<unsigned int>
+    ConvertMesh(const MeshGeometry &mesh, const Model &model, aiNode *parent, aiNode *root_node,
+                const aiMatrix4x4 &absolute_transform);
 
     // ------------------------------------------------------------------------------------------------
     std::vector<unsigned int> ConvertLine(const LineGeometry& line, const Model& model,
-        const aiMatrix4x4& node_global_transform, aiNode& nd);
+                                          aiNode *parent, aiNode *root_node);
 
     // ------------------------------------------------------------------------------------------------
-    aiMesh* SetupEmptyMesh(const Geometry& mesh, aiNode& nd);
+    aiMesh* SetupEmptyMesh(const Geometry& mesh, aiNode *parent);
 
     // ------------------------------------------------------------------------------------------------
-    unsigned int ConvertMeshSingleMaterial(const MeshGeometry& mesh, const Model& model,
-        const aiMatrix4x4& node_global_transform, aiNode& nd);
+    unsigned int ConvertMeshSingleMaterial(const MeshGeometry &mesh, const Model &model,
+                                           const aiMatrix4x4 &absolute_transform, aiNode *parent,
+                                           aiNode *root_node);
 
     // ------------------------------------------------------------------------------------------------
-    std::vector<unsigned int> ConvertMeshMultiMaterial(const MeshGeometry& mesh, const Model& model,
-        const aiMatrix4x4& node_global_transform, aiNode& nd);
+    std::vector<unsigned int>
+    ConvertMeshMultiMaterial(const MeshGeometry &mesh, const Model &model, aiNode *parent, aiNode *root_node,
+                             const aiMatrix4x4 &absolute_transform);
 
     // ------------------------------------------------------------------------------------------------
-    unsigned int ConvertMeshMultiMaterial(const MeshGeometry& mesh, const Model& model,
-        MatIndexArray::value_type index,
-        const aiMatrix4x4& node_global_transform, aiNode& nd);
+    unsigned int ConvertMeshMultiMaterial(const MeshGeometry &mesh, const Model &model, MatIndexArray::value_type index,
+                                          aiNode *parent, aiNode *root_node, const aiMatrix4x4 &absolute_transform);
 
     // ------------------------------------------------------------------------------------------------
     static const unsigned int NO_MATERIAL_SEPARATION = /* std::numeric_limits<unsigned int>::max() */
@@ -227,17 +220,17 @@ private:
     *  - outputVertStartIndices is only used when a material index is specified, it gives for
     *    each output vertex the DOM index it maps to.
     */
-    void ConvertWeights(aiMesh* out, const Model& model, const MeshGeometry& geo,
-        const aiMatrix4x4& node_global_transform = aiMatrix4x4(),
-        unsigned int materialIndex = NO_MATERIAL_SEPARATION,
-        std::vector<unsigned int>* outputVertStartIndices = NULL);
-
+    void ConvertWeights(aiMesh *out, const Model &model, const MeshGeometry &geo, const aiMatrix4x4 &absolute_transform,
+                        aiNode *parent = NULL, aiNode *root_node = NULL,
+                        unsigned int materialIndex = NO_MATERIAL_SEPARATION,
+                        std::vector<unsigned int> *outputVertStartIndices = NULL);
+    // lookup
+    static const aiNode* GetNodeByName( const aiString& name, aiNode *current_node );
     // ------------------------------------------------------------------------------------------------
-    void ConvertCluster(std::vector<aiBone*>& bones, const Model& /*model*/, const Cluster& cl,
-        std::vector<size_t>& out_indices,
-        std::vector<size_t>& index_out_indices,
-        std::vector<size_t>& count_out_indices,
-        const aiMatrix4x4& node_global_transform);
+    void ConvertCluster(std::vector<aiBone *> &local_mesh_bones, const Cluster *cl,
+                        std::vector<size_t> &out_indices, std::vector<size_t> &index_out_indices,
+                        std::vector<size_t> &count_out_indices, const aiMatrix4x4 &absolute_transform,
+                        aiNode *parent, aiNode *root_node);
 
     // ------------------------------------------------------------------------------------------------
     void ConvertMaterialForMesh(aiMesh* out, const Model& model, const MeshGeometry& geo,
@@ -462,11 +455,30 @@ private:
     using NodeNameCache = std::unordered_map<std::string, unsigned int>;
     NodeNameCache mNodeNames;
 
+    // Deformer name is not the same as a bone name - it does contain the bone name though :)
+    // Deformer names in FBX are always unique in an FBX file.
+    std::map<const std::string, aiBone *> bone_map;
+
     double anim_fps;
 
     aiScene* const out;
     const FBX::Document& doc;
-    FbxUnit mCurrentUnit;
+
+    static void BuildBoneList(aiNode *current_node, const aiNode *root_node, const aiScene *scene,
+                             std::vector<aiBone*>& bones);
+
+    void BuildBoneStack(aiNode *current_node, const aiNode *root_node, const aiScene *scene,
+                   const std::vector<aiBone *> &bones,
+                   std::map<aiBone *, aiNode *> &bone_stack,
+                   std::vector<aiNode*> &node_stack );
+
+    static void BuildNodeList(aiNode *current_node, std::vector<aiNode *> &nodes);
+
+    static aiNode *GetNodeFromStack(const aiString &node_name, std::vector<aiNode *> &nodes);
+
+    static aiNode *GetArmatureRoot(aiNode *bone_node, std::vector<aiBone*> &bone_list);
+
+    static bool IsBoneNode(const aiString &bone_name, std::vector<aiBone *> &bones);
 };
 
 }
diff --git a/thirdparty/assimp/code/FBX/FBXExportProperty.cpp b/thirdparty/assimp/code/FBX/FBXExportProperty.cpp
index f8593e6295..f2a63b72b9 100644
--- a/thirdparty/assimp/code/FBX/FBXExportProperty.cpp
+++ b/thirdparty/assimp/code/FBX/FBXExportProperty.cpp
@@ -59,11 +59,7 @@ namespace FBX {
 
 FBXExportProperty::FBXExportProperty(bool v)
 : type('C')
-, data(1) {
-    data = {
-        uint8_t(v)
-    };
-}
+, data(1, uint8_t(v)) {}
 
 FBXExportProperty::FBXExportProperty(int16_t v)
 : type('Y')
diff --git a/thirdparty/assimp/code/FBX/FBXExporter.cpp b/thirdparty/assimp/code/FBX/FBXExporter.cpp
index 8ebc8555a2..25d057df1c 100644
--- a/thirdparty/assimp/code/FBX/FBXExporter.cpp
+++ b/thirdparty/assimp/code/FBX/FBXExporter.cpp
@@ -67,6 +67,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <vector>
 #include <array>
 #include <unordered_set>
+#include <numeric>
 
 // RESOURCES:
 // https://code.blender.org/2013/08/fbx-binary-file-format-specification/
@@ -1005,6 +1006,9 @@ void FBXExporter::WriteObjects ()
     object_node.EndProperties(outstream, binary, indent);
     object_node.BeginChildren(outstream, binary, indent);
 
+    bool bJoinIdenticalVertices = mProperties->GetPropertyBool("bJoinIdenticalVertices", true);
+    std::vector<std::vector<int32_t>> vVertexIndice;//save vertex_indices as it is needed later
+
     // geometry (aiMesh)
     mesh_uids.clear();
     indent = 1;
@@ -1031,21 +1035,35 @@ void FBXExporter::WriteObjects ()
         std::vector<int32_t> vertex_indices;
         // map of vertex value to its index in the data vector
         std::map<aiVector3D,size_t> index_by_vertex_value;
-        int32_t index = 0;
-        for (size_t vi = 0; vi < m->mNumVertices; ++vi) {
-            aiVector3D vtx = m->mVertices[vi];
-            auto elem = index_by_vertex_value.find(vtx);
-            if (elem == index_by_vertex_value.end()) {
-                vertex_indices.push_back(index);
-                index_by_vertex_value[vtx] = index;
-                flattened_vertices.push_back(vtx[0]);
-                flattened_vertices.push_back(vtx[1]);
-                flattened_vertices.push_back(vtx[2]);
-                ++index;
-            } else {
-                vertex_indices.push_back(int32_t(elem->second));
+        if(bJoinIdenticalVertices){
+            int32_t index = 0;
+            for (size_t vi = 0; vi < m->mNumVertices; ++vi) {
+                aiVector3D vtx = m->mVertices[vi];
+                auto elem = index_by_vertex_value.find(vtx);
+                if (elem == index_by_vertex_value.end()) {
+                    vertex_indices.push_back(index);
+                    index_by_vertex_value[vtx] = index;
+                    flattened_vertices.push_back(vtx[0]);
+                    flattened_vertices.push_back(vtx[1]);
+                    flattened_vertices.push_back(vtx[2]);
+                    ++index;
+                } else {
+                    vertex_indices.push_back(int32_t(elem->second));
+                }
+            }
+        }
+        else { // do not join vertex, respect the export flag
+            vertex_indices.resize(m->mNumVertices);
+            std::iota(vertex_indices.begin(), vertex_indices.end(), 0);
+            for(unsigned int v = 0; v < m->mNumVertices; ++ v) {
+                aiVector3D vtx = m->mVertices[v];
+                flattened_vertices.push_back(vtx.x);
+                flattened_vertices.push_back(vtx.y);
+                flattened_vertices.push_back(vtx.z);
             }
         }
+        vVertexIndice.push_back(vertex_indices);
+
         FBX::Node::WritePropertyNode(
             "Vertices", flattened_vertices, outstream, binary, indent
         );
@@ -1116,6 +1134,51 @@ void FBXExporter::WriteObjects ()
             normals.End(outstream, binary, indent, true);
         }
 
+        // colors, if any
+        // TODO only one color channel currently
+        const int32_t colorChannelIndex = 0;
+        if (m->HasVertexColors(colorChannelIndex)) {
+            FBX::Node vertexcolors("LayerElementColor", int32_t(colorChannelIndex));
+            vertexcolors.Begin(outstream, binary, indent);
+            vertexcolors.DumpProperties(outstream, binary, indent);
+            vertexcolors.EndProperties(outstream, binary, indent);
+            vertexcolors.BeginChildren(outstream, binary, indent);
+            indent = 3;
+            FBX::Node::WritePropertyNode(
+                "Version", int32_t(101), outstream, binary, indent
+            );
+            char layerName[8];
+            sprintf(layerName, "COLOR_%d", colorChannelIndex);
+            FBX::Node::WritePropertyNode(
+                "Name", (const char*)layerName, outstream, binary, indent
+            );
+            FBX::Node::WritePropertyNode(
+                "MappingInformationType", "ByPolygonVertex",
+                outstream, binary, indent
+            );
+            FBX::Node::WritePropertyNode(
+                "ReferenceInformationType", "Direct",
+                outstream, binary, indent
+            );
+            std::vector<double> color_data;
+            color_data.reserve(4 * polygon_data.size());
+            for (size_t fi = 0; fi < m->mNumFaces; ++fi) {
+                const aiFace &f = m->mFaces[fi];
+                for (size_t pvi = 0; pvi < f.mNumIndices; ++pvi) {
+                    const aiColor4D &c = m->mColors[colorChannelIndex][f.mIndices[pvi]];
+                    color_data.push_back(c.r);
+                    color_data.push_back(c.g);
+                    color_data.push_back(c.b);
+                    color_data.push_back(c.a);
+                }
+            }
+            FBX::Node::WritePropertyNode(
+                "Colors", color_data, outstream, binary, indent
+            );
+            indent = 2;
+            vertexcolors.End(outstream, binary, indent, true);
+        }
+        
         // uvs, if any
         for (size_t uvi = 0; uvi < m->GetNumUVChannels(); ++uvi) {
             if (m->mNumUVComponents[uvi] > 2) {
@@ -1209,6 +1272,11 @@ void FBXExporter::WriteObjects ()
         le.AddChild("Type", "LayerElementNormal");
         le.AddChild("TypedIndex", int32_t(0));
         layer.AddChild(le);
+        // TODO only 1 color channel currently
+        le = FBX::Node("LayerElement");
+        le.AddChild("Type", "LayerElementColor");
+        le.AddChild("TypedIndex", int32_t(0));
+        layer.AddChild(le);
         le = FBX::Node("LayerElement");
         le.AddChild("Type", "LayerElementMaterial");
         le.AddChild("TypedIndex", int32_t(0));
@@ -1748,28 +1816,8 @@ void FBXExporter::WriteObjects ()
         // connect it
         connections.emplace_back("C", "OO", deformer_uid, mesh_uids[mi]);
 
-        // we will be indexing by vertex...
-        // but there might be a different number of "vertices"
-        // between assimp and our output FBX.
-        // this code is cut-and-pasted from the geometry section above...
-        // ideally this should not be so.
-        // ---
-        // index of original vertex in vertex data vector
-        std::vector<int32_t> vertex_indices;
-        // map of vertex value to its index in the data vector
-        std::map<aiVector3D,size_t> index_by_vertex_value;
-        int32_t index = 0;
-        for (size_t vi = 0; vi < m->mNumVertices; ++vi) {
-            aiVector3D vtx = m->mVertices[vi];
-            auto elem = index_by_vertex_value.find(vtx);
-            if (elem == index_by_vertex_value.end()) {
-                vertex_indices.push_back(index);
-                index_by_vertex_value[vtx] = index;
-                ++index;
-            } else {
-                vertex_indices.push_back(int32_t(elem->second));
-            }
-        }
+        //computed before
+        std::vector<int32_t>& vertex_indices = vVertexIndice[mi];
 
         // TODO, FIXME: this won't work if anything is not in the bind pose.
         // for now if such a situation is detected, we throw an exception.
@@ -2435,7 +2483,7 @@ void FBXExporter::WriteModelNodes(
 void FBXExporter::WriteAnimationCurveNode(
     StreamWriterLE& outstream,
     int64_t uid,
-    std::string name, // "T", "R", or "S"
+    const std::string& name, // "T", "R", or "S"
     aiVector3D default_value,
     std::string property_name, // "Lcl Translation" etc
     int64_t layer_uid,
diff --git a/thirdparty/assimp/code/FBX/FBXExporter.h b/thirdparty/assimp/code/FBX/FBXExporter.h
index 71fb55c57f..1ae727eda9 100644
--- a/thirdparty/assimp/code/FBX/FBXExporter.h
+++ b/thirdparty/assimp/code/FBX/FBXExporter.h
@@ -156,7 +156,7 @@ namespace Assimp
         void WriteAnimationCurveNode(
             StreamWriterLE& outstream,
             int64_t uid,
-            std::string name, // "T", "R", or "S"
+            const std::string& name, // "T", "R", or "S"
             aiVector3D default_value,
             std::string property_name, // "Lcl Translation" etc
             int64_t animation_layer_uid,
diff --git a/thirdparty/assimp/code/FBX/FBXImporter.cpp b/thirdparty/assimp/code/FBX/FBXImporter.cpp
index 271935a568..afcc1ddc78 100644
--- a/thirdparty/assimp/code/FBX/FBXImporter.cpp
+++ b/thirdparty/assimp/code/FBX/FBXImporter.cpp
@@ -48,26 +48,26 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "FBXImporter.h"
 
-#include "FBXTokenizer.h"
+#include "FBXConverter.h"
+#include "FBXDocument.h"
 #include "FBXParser.h"
+#include "FBXTokenizer.h"
 #include "FBXUtil.h"
-#include "FBXDocument.h"
-#include "FBXConverter.h"
 
-#include <assimp/StreamReader.h>
 #include <assimp/MemoryIOWrapper.h>
-#include <assimp/Importer.hpp>
+#include <assimp/StreamReader.h>
 #include <assimp/importerdesc.h>
+#include <assimp/Importer.hpp>
 
 namespace Assimp {
 
-template<>
-const char* LogFunctions<FBXImporter>::Prefix() {
-    static auto prefix = "FBX: ";
-    return prefix;
+template <>
+const char *LogFunctions<FBXImporter>::Prefix() {
+	static auto prefix = "FBX: ";
+	return prefix;
 }
 
-}
+} // namespace Assimp
 
 using namespace Assimp;
 using namespace Assimp::Formatter;
@@ -76,136 +76,123 @@ using namespace Assimp::FBX;
 namespace {
 
 static const aiImporterDesc desc = {
-    "Autodesk FBX Importer",
-    "",
-    "",
-    "",
-    aiImporterFlags_SupportTextFlavour,
-    0,
-    0,
-    0,
-    0,
-    "fbx"
+	"Autodesk FBX Importer",
+	"",
+	"",
+	"",
+	aiImporterFlags_SupportTextFlavour,
+	0,
+	0,
+	0,
+	0,
+	"fbx"
 };
 }
 
 // ------------------------------------------------------------------------------------------------
 // Constructor to be privately used by #Importer
-FBXImporter::FBXImporter()
-{
+FBXImporter::FBXImporter() {
 }
 
 // ------------------------------------------------------------------------------------------------
 // Destructor, private as well
-FBXImporter::~FBXImporter()
-{
+FBXImporter::~FBXImporter() {
 }
 
 // ------------------------------------------------------------------------------------------------
 // Returns whether the class can handle the format of the given file.
-bool FBXImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool checkSig) const
-{
-    const std::string& extension = GetExtension(pFile);
-    if (extension == std::string( desc.mFileExtensions ) ) {
-        return true;
-    }
-
-    else if ((!extension.length() || checkSig) && pIOHandler)   {
-        // at least ASCII-FBX files usually have a 'FBX' somewhere in their head
-        const char* tokens[] = {"fbx"};
-        return SearchFileHeaderForToken(pIOHandler,pFile,tokens,1);
-    }
-    return false;
+bool FBXImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool checkSig) const {
+	const std::string &extension = GetExtension(pFile);
+	if (extension == std::string(desc.mFileExtensions)) {
+		return true;
+	}
+
+	else if ((!extension.length() || checkSig) && pIOHandler) {
+		// at least ASCII-FBX files usually have a 'FBX' somewhere in their head
+		const char *tokens[] = { "fbx" };
+		return SearchFileHeaderForToken(pIOHandler, pFile, tokens, 1);
+	}
+	return false;
 }
 
 // ------------------------------------------------------------------------------------------------
 // List all extensions handled by this loader
-const aiImporterDesc* FBXImporter::GetInfo () const
-{
-    return &desc;
+const aiImporterDesc *FBXImporter::GetInfo() const {
+	return &desc;
 }
 
 // ------------------------------------------------------------------------------------------------
 // Setup configuration properties for the loader
-void FBXImporter::SetupProperties(const Importer* pImp)
-{
-    settings.readAllLayers = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_ALL_GEOMETRY_LAYERS, true);
-    settings.readAllMaterials = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_ALL_MATERIALS, false);
-    settings.readMaterials = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_MATERIALS, true);
-    settings.readTextures = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_TEXTURES, true);
-    settings.readCameras = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_CAMERAS, true);
-    settings.readLights = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_LIGHTS, true);
-    settings.readAnimations = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_ANIMATIONS, true);
-    settings.strictMode = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_STRICT_MODE, false);
-    settings.preservePivots = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_PRESERVE_PIVOTS, true);
-    settings.optimizeEmptyAnimationCurves = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_OPTIMIZE_EMPTY_ANIMATION_CURVES, true);
-    settings.useLegacyEmbeddedTextureNaming = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_EMBEDDED_TEXTURES_LEGACY_NAMING, false);
-    settings.removeEmptyBones = pImp->GetPropertyBool(AI_CONFIG_IMPORT_REMOVE_EMPTY_BONES, true);
-    settings.convertToMeters = pImp->GetPropertyBool(AI_CONFIG_FBX_CONVERT_TO_M, false);
+void FBXImporter::SetupProperties(const Importer *pImp) {
+	settings.readAllLayers = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_ALL_GEOMETRY_LAYERS, true);
+	settings.readAllMaterials = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_ALL_MATERIALS, false);
+	settings.readMaterials = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_MATERIALS, true);
+	settings.readTextures = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_TEXTURES, true);
+	settings.readCameras = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_CAMERAS, true);
+	settings.readLights = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_LIGHTS, true);
+	settings.readAnimations = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_READ_ANIMATIONS, true);
+	settings.strictMode = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_STRICT_MODE, false);
+	settings.preservePivots = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_PRESERVE_PIVOTS, true);
+	settings.optimizeEmptyAnimationCurves = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_OPTIMIZE_EMPTY_ANIMATION_CURVES, true);
+	settings.useLegacyEmbeddedTextureNaming = pImp->GetPropertyBool(AI_CONFIG_IMPORT_FBX_EMBEDDED_TEXTURES_LEGACY_NAMING, false);
+	settings.removeEmptyBones = pImp->GetPropertyBool(AI_CONFIG_IMPORT_REMOVE_EMPTY_BONES, true);
+	settings.convertToMeters = pImp->GetPropertyBool(AI_CONFIG_FBX_CONVERT_TO_M, false);
 }
 
 // ------------------------------------------------------------------------------------------------
 // Imports the given file into the given scene structure.
-void FBXImporter::InternReadFile( const std::string& pFile, aiScene* pScene, IOSystem* pIOHandler)
-{
-    std::unique_ptr<IOStream> stream(pIOHandler->Open(pFile,"rb"));
-    if (!stream) {
-        ThrowException("Could not open file for reading");
-    }
-
-    // read entire file into memory - no streaming for this, fbx
-    // files can grow large, but the assimp output data structure
-    // then becomes very large, too. Assimp doesn't support
-    // streaming for its output data structures so the net win with
-    // streaming input data would be very low.
-    std::vector<char> contents;
-    contents.resize(stream->FileSize()+1);
-    stream->Read( &*contents.begin(), 1, contents.size()-1 );
-    contents[ contents.size() - 1 ] = 0;
-    const char* const begin = &*contents.begin();
-
-    // broadphase tokenizing pass in which we identify the core
-    // syntax elements of FBX (brackets, commas, key:value mappings)
-    TokenList tokens;
-    try {
-
-        bool is_binary = false;
-        if (!strncmp(begin,"Kaydara FBX Binary",18)) {
-            is_binary = true;
-            TokenizeBinary(tokens,begin,contents.size());
-        }
-        else {
-            Tokenize(tokens,begin);
-        }
-
-        // use this information to construct a very rudimentary
-        // parse-tree representing the FBX scope structure
-        Parser parser(tokens, is_binary);
-
-        // take the raw parse-tree and convert it to a FBX DOM
-        Document doc(parser,settings);
-
-        FbxUnit unit(FbxUnit::cm);
-        if (settings.convertToMeters) {
-            unit = FbxUnit::m;
-        }
-
-        // convert the FBX DOM to aiScene
-        ConvertToAssimpScene(pScene, doc, settings.removeEmptyBones);
-
-        // size relative to cm
-        float size_relative_to_cm = doc.GlobalSettings().UnitScaleFactor();
-
-        // Set FBX file scale is relative to CM must be converted to M for
-        // assimp universal format (M)
-        SetFileScale( size_relative_to_cm * 0.01f);
-
-        std::for_each(tokens.begin(),tokens.end(),Util::delete_fun<Token>());
-    }
-    catch(std::exception&) {
-        std::for_each(tokens.begin(),tokens.end(),Util::delete_fun<Token>());
-        throw;
-    }
+void FBXImporter::InternReadFile(const std::string &pFile, aiScene *pScene, IOSystem *pIOHandler) {
+	std::unique_ptr<IOStream> stream(pIOHandler->Open(pFile, "rb"));
+	if (!stream) {
+		ThrowException("Could not open file for reading");
+	}
+
+	// read entire file into memory - no streaming for this, fbx
+	// files can grow large, but the assimp output data structure
+	// then becomes very large, too. Assimp doesn't support
+	// streaming for its output data structures so the net win with
+	// streaming input data would be very low.
+	std::vector<char> contents;
+	contents.resize(stream->FileSize() + 1);
+	stream->Read(&*contents.begin(), 1, contents.size() - 1);
+	contents[contents.size() - 1] = 0;
+	const char *const begin = &*contents.begin();
+
+	// broadphase tokenizing pass in which we identify the core
+	// syntax elements of FBX (brackets, commas, key:value mappings)
+	TokenList tokens;
+	try {
+
+		bool is_binary = false;
+		if (!strncmp(begin, "Kaydara FBX Binary", 18)) {
+			is_binary = true;
+			TokenizeBinary(tokens, begin, contents.size());
+		} else {
+			Tokenize(tokens, begin);
+		}
+
+		// use this information to construct a very rudimentary
+		// parse-tree representing the FBX scope structure
+		Parser parser(tokens, is_binary);
+
+		// take the raw parse-tree and convert it to a FBX DOM
+		Document doc(parser, settings);
+
+		// convert the FBX DOM to aiScene
+		ConvertToAssimpScene(pScene, doc, settings.removeEmptyBones);
+
+		// size relative to cm
+		float size_relative_to_cm = doc.GlobalSettings().UnitScaleFactor();
+
+		// Set FBX file scale is relative to CM must be converted to M for
+		// assimp universal format (M)
+		SetFileScale(size_relative_to_cm * 0.01f);
+
+		std::for_each(tokens.begin(), tokens.end(), Util::delete_fun<Token>());
+	} catch (std::exception &) {
+		std::for_each(tokens.begin(), tokens.end(), Util::delete_fun<Token>());
+		throw;
+	}
 }
 
 #endif // !ASSIMP_BUILD_NO_FBX_IMPORTER
diff --git a/thirdparty/assimp/code/FBX/FBXMeshGeometry.cpp b/thirdparty/assimp/code/FBX/FBXMeshGeometry.cpp
index 5c9a0e309d..1386e2383c 100644
--- a/thirdparty/assimp/code/FBX/FBXMeshGeometry.cpp
+++ b/thirdparty/assimp/code/FBX/FBXMeshGeometry.cpp
@@ -610,11 +610,11 @@ void MeshGeometry::ReadVertexDataMaterials(std::vector<int>& materials_out, cons
     const std::string& ReferenceInformationType)
 {
     const size_t face_count = m_faces.size();
-    if(face_count <= 0)
+    if( 0 == face_count )
     {
         return;
     }
-
+    
     // materials are handled separately. First of all, they are assigned per-face
     // and not per polyvert. Secondly, ReferenceInformationType=IndexToDirect
     // has a slightly different meaning for materials.
@@ -625,16 +625,14 @@ void MeshGeometry::ReadVertexDataMaterials(std::vector<int>& materials_out, cons
         if (materials_out.empty()) {
             FBXImporter::LogError(Formatter::format("expected material index, ignoring"));
             return;
-        }
-        else if (materials_out.size() > 1) {
+        } else if (materials_out.size() > 1) {
             FBXImporter::LogWarn(Formatter::format("expected only a single material index, ignoring all except the first one"));
             materials_out.clear();
         }
 
         materials_out.resize(m_vertices.size());
         std::fill(materials_out.begin(), materials_out.end(), materials_out.at(0));
-    }
-    else if (MappingInformationType == "ByPolygon" && ReferenceInformationType == "IndexToDirect") {
+    } else if (MappingInformationType == "ByPolygon" && ReferenceInformationType == "IndexToDirect") {
         materials_out.resize(face_count);
 
         if(materials_out.size() != face_count) {
@@ -643,18 +641,16 @@ void MeshGeometry::ReadVertexDataMaterials(std::vector<int>& materials_out, cons
             );
             return;
         }
-    }
-    else {
+    } else {
         FBXImporter::LogError(Formatter::format("ignoring material assignments, access type not implemented: ")
             << MappingInformationType << "," << ReferenceInformationType);
     }
 }
 // ------------------------------------------------------------------------------------------------
 ShapeGeometry::ShapeGeometry(uint64_t id, const Element& element, const std::string& name, const Document& doc)
-    : Geometry(id, element, name, doc)
-{
-    const Scope* sc = element.Compound();
-    if (!sc) {
+: Geometry(id, element, name, doc) {
+    const Scope *sc = element.Compound();
+    if (nullptr == sc) {
         DOMError("failed to read Geometry object (class: Shape), no data scope found");
     }
     const Element& Indexes = GetRequiredElement(*sc, "Indexes", &element);