4 files changed, 25 insertions, 12 deletions

diff --git a/scene/3d/mesh_instance_3d.cpp b/scene/3d/mesh_instance_3d.cpp
index 10f3ab5c79..16de95bfb1 100644
--- a/scene/3d/mesh_instance_3d.cpp
+++ b/scene/3d/mesh_instance_3d.cpp
@@ -53,21 +53,22 @@ bool MeshInstance3D::_set(const StringName &p_name, const Variant &p_value) {
 	if (p_name.operator String().begins_with("surface_material_override/")) {
 		int idx = p_name.operator String().get_slicec('/', 1).to_int();
 
-		// This is a bit of a hack to ensure compatibility with older material
-		// overrides that start indexing at 0.
+		// This is a bit of a hack to ensure compatibility with material
+		// overrides that start indexing at 1.
 		// We assume that idx 0 is always read first, if its not, this won't work.
 		if (idx == 0) {
-			old_surface_index = true;
+			surface_index_0 = true;
 		}
-		if (old_surface_index) {
-			idx++;
+		if (!surface_index_0) {
+			// This means the file was created when the indexing started at 1, so decrease by one.
+			idx--;
 		}
 
 		if (idx > surface_override_materials.size() || idx < 0) {
 			return false;
 		}
 
-		set_surface_override_material(idx - 1, p_value);
+		set_surface_override_material(idx, p_value);
 		return true;
 	}
 
@@ -86,7 +87,7 @@ bool MeshInstance3D::_get(const StringName &p_name, Variant &r_ret) const {
 	}
 
 	if (p_name.operator String().begins_with("surface_material_override/")) {
-		int idx = p_name.operator String().get_slicec('/', 1).to_int() - 1;
+		int idx = p_name.operator String().get_slicec('/', 1).to_int();
 		if (idx >= surface_override_materials.size() || idx < 0) {
 			return false;
 		}
@@ -109,7 +110,7 @@ void MeshInstance3D::_get_property_list(List<PropertyInfo> *p_list) const {
 	}
 
 	if (mesh.is_valid()) {
-		for (int i = 1; i <= mesh->get_surface_count(); i++) {
+		for (int i = 0; i < mesh->get_surface_count(); i++) {
 			p_list->push_back(PropertyInfo(Variant::OBJECT, vformat("%s/%d", PNAME("surface_material_override"), i), PROPERTY_HINT_RESOURCE_TYPE, "BaseMaterial3D,ShaderMaterial", PROPERTY_USAGE_DEFAULT | PROPERTY_USAGE_DEFERRED_SET_RESOURCE));
 		}
 	}
diff --git a/scene/3d/mesh_instance_3d.h b/scene/3d/mesh_instance_3d.h
index 9e6dbaf160..e1cc5272ea 100644
--- a/scene/3d/mesh_instance_3d.h
+++ b/scene/3d/mesh_instance_3d.h
@@ -57,7 +57,7 @@ protected:
 	bool _set(const StringName &p_name, const Variant &p_value);
 	bool _get(const StringName &p_name, Variant &r_ret) const;
 	void _get_property_list(List<PropertyInfo> *p_list) const;
-	bool old_surface_index = false;
+	bool surface_index_0 = false;
 
 	void _notification(int p_what);
 	static void _bind_methods();
diff --git a/scene/3d/visual_instance_3d.cpp b/scene/3d/visual_instance_3d.cpp
index 0f214ecd97..c027e33ad3 100644
--- a/scene/3d/visual_instance_3d.cpp
+++ b/scene/3d/visual_instance_3d.cpp
@@ -338,8 +338,16 @@ Variant GeometryInstance3D::get_instance_shader_parameter(const StringName &p_na
 	return RS::get_singleton()->instance_geometry_get_shader_parameter(get_instance(), p_name);
 }
 
-void GeometryInstance3D::set_custom_aabb(AABB aabb) {
-	RS::get_singleton()->instance_set_custom_aabb(get_instance(), aabb);
+void GeometryInstance3D::set_custom_aabb(AABB p_aabb) {
+	if (p_aabb == custom_aabb) {
+		return;
+	}
+	custom_aabb = p_aabb;
+	RS::get_singleton()->instance_set_custom_aabb(get_instance(), custom_aabb);
+}
+
+AABB GeometryInstance3D::get_custom_aabb() const {
+	return custom_aabb;
 }
 
 void GeometryInstance3D::set_lightmap_scale(LightmapScale p_scale) {
@@ -449,6 +457,7 @@ void GeometryInstance3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("is_ignoring_occlusion_culling"), &GeometryInstance3D::is_ignoring_occlusion_culling);
 
 	ClassDB::bind_method(D_METHOD("set_custom_aabb", "aabb"), &GeometryInstance3D::set_custom_aabb);
+	ClassDB::bind_method(D_METHOD("get_custom_aabb"), &GeometryInstance3D::get_custom_aabb);
 
 	ClassDB::bind_method(D_METHOD("get_aabb"), &GeometryInstance3D::get_aabb);
 
@@ -458,6 +467,7 @@ void GeometryInstance3D::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "transparency", PROPERTY_HINT_RANGE, "0.0,1.0,0.01"), "set_transparency", "get_transparency");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "cast_shadow", PROPERTY_HINT_ENUM, "Off,On,Double-Sided,Shadows Only"), "set_cast_shadows_setting", "get_cast_shadows_setting");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "extra_cull_margin", PROPERTY_HINT_RANGE, "0,16384,0.01,suffix:m"), "set_extra_cull_margin", "get_extra_cull_margin");
+	ADD_PROPERTY(PropertyInfo(Variant::AABB, "custom_aabb", PROPERTY_HINT_NONE, "suffix:m"), "set_custom_aabb", "get_custom_aabb");
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "lod_bias", PROPERTY_HINT_RANGE, "0.001,128,0.001"), "set_lod_bias", "get_lod_bias");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "ignore_occlusion_culling"), "set_ignore_occlusion_culling", "is_ignoring_occlusion_culling");
 
diff --git a/scene/3d/visual_instance_3d.h b/scene/3d/visual_instance_3d.h
index f18bff2ddc..c741ef710d 100644
--- a/scene/3d/visual_instance_3d.h
+++ b/scene/3d/visual_instance_3d.h
@@ -121,6 +121,7 @@ private:
 	mutable HashMap<StringName, StringName> instance_shader_parameter_property_remap;
 
 	float extra_cull_margin = 0.0;
+	AABB custom_aabb;
 	LightmapScale lightmap_scale = LIGHTMAP_SCALE_1X;
 	GIMode gi_mode = GI_MODE_STATIC;
 	bool ignore_occlusion_culling = false;
@@ -177,7 +178,8 @@ public:
 	void set_instance_shader_parameter(const StringName &p_name, const Variant &p_value);
 	Variant get_instance_shader_parameter(const StringName &p_name) const;
 
-	void set_custom_aabb(AABB aabb);
+	void set_custom_aabb(AABB p_aabb);
+	AABB get_custom_aabb() const;
 
 	void set_ignore_occlusion_culling(bool p_enabled);
 	bool is_ignoring_occlusion_culling();