diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7c621b4..a4fa2cc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -27,6 +27,7 @@ endif()
 # DRACO
 ExternalProject_Add(Draco
   GIT_REPOSITORY https://github.com/google/draco
+  GIT_TAG 1.2.0
   PREFIX draco
   GIT_TAG 1.2.0
   INSTALL_DIR
@@ -76,6 +77,16 @@ ExternalProject_Add(Json
 )
 set(JSON_INCLUDE_DIR "${CMAKE_BINARY_DIR}/json/src/Json/src")
 
+# stb
+ExternalProject_Add(STB
+  PREFIX stb
+  GIT_REPOSITORY https://github.com/nothings/stb
+  CONFIGURE_COMMAND ${CMAKE_COMMAND} -E echo "Skipping STB configure step."
+  BUILD_COMMAND ${CMAKE_COMMAND} -E echo "Skipping STB build step."
+  INSTALL_COMMAND ${CMAKE_COMMAND} -E echo "Skipping STB install step."
+)
+set(STB_INCLUDE_DIR "${CMAKE_BINARY_DIR}/stb/src/STB")
+
 # cppcodec
 ExternalProject_Add(CPPCodec
   PREFIX cppcodec
@@ -151,6 +162,7 @@ add_dependencies(FBX2glTF
   MathFu
   FiFoMap
   Json
+  STB
   CxxOpts
   CPPCodec
   Fmt
@@ -182,6 +194,7 @@ target_include_directories(FBX2glTF PUBLIC
   ${FIFO_MAP_INCLUDE_DIR}
   ${JSON_INCLUDE_DIR}
   ${CXXOPTS_INCLUDE_DIR}
+  ${STB_INCLUDE_DIR}
   ${CPPCODEC_INCLUDE_DIR}
   ${FMT_INCLUDE_DIR}
 )
diff --git a/README.md b/README.md
index aa2ec16..baedf00 100644
--- a/README.md
+++ b/README.md
@@ -44,9 +44,10 @@ Usage:
       --khr-materials-common    (WIP) Use KHR_materials_common extensions to
                                 specify Unlit/Lambert/Blinn/Phong shaders.
       --pbr-metallic-roughness  (WIP) Try to glean glTF 2.0 native PBR
-                                attributes from the FBX.
+                                attributes from the FBX, or make a best effort
+                                to convert from traditional shader models.
       --pbr-specular-glossiness
-                                (WIP) Experimentally fill in the
+                                (WIP) Very experimentally employ the
                                 KHR_materials_pbrSpecularGlossiness extension.
       --blend-shape-normals     Include blend shape normals, if reported
                                 present by the FBX SDK.
@@ -192,50 +193,68 @@ With glTF 2.0, we leaped headlong into physically-based rendering (BPR), where
 the canonical way of expressing what a mesh looks like is by describing its
 visible material in fundamental attributes like "how rough is this surface".
 
-By contrast, FBX's material support remains in the older world of Lambert and
-Phong, with simpler and more direct illumination and shading models. These modes
-are largely incompatible — for example, textures in the old workflow often
-contain baked lighting, which would arise naturally in a PBR environment.
+By contrast, FBX's material support remains largely in the older world of
+Lambert and Phong, with simpler and more direct illumination and shading
+models. These modes are inherently incompatible — for example, textures in the
+old workflow often contain baked lighting of the type that would arise naturally
+in a PBR environment.
 
 Some material settings remain well supported and transfer automatically:
  - Emissive constants and textures
  - Occlusion maps
  - Normal maps
 
-This leaves the other traditional settings of Lambert:
+This leaves the other traditional settings, first of Lambert:
  - Ambient — this is anathema in the PBR world, where such effects should
    emerge naturally from the fundamental colour of the material and any ambient
    lighting present.
  - Diffuse — the material's direction-agnostic, non-specular reflection,
 and additionally, with Blinn/Phong:
  - Specular — a more polished material's direction-sensitive reflection,
- - Shininess — just how polished the material is,
+ - Shininess — just how polished the material is; a higher value here yields a
+   more mirror-like surface.
 
 (All these can be either constants or textures.)
 
 #### Exporting as Unlit/Lambert/Phong 
-Increasingly with PBR materials, these properties are just left at zero or
-default values in the FBX. But when they're there, and they're how you want the
-glTF materials generated, one option is to use the --khr-materials-common
-command line switch, with the awareness that this incurs a required dependency
-on the glTF extension `KHR_materials_common`.
+If you have a model was constructed using the traditional workflow, you may
+choose to export it using the --khr-materials-common switch. This incurs a
+dependency on the glTF extension 'KHR_materials_common'; a client that accepts
+that extension is making a promise it'll do its best to render i.e. Lambert or
+Phong.
+
+You can use this flag even for PBR models, but the conversion is imperfect to
+say the least, and there is no reason why you would ever want to do such a
+thing.
 
 **Note that at the time of writing, this glTF extension is still undergoing the
 ratification process, and is furthermore likely to change names.**
 
 #### Exporting as Metallic-Roughness PBR
-Given the command line flag --pbr-metallic-roughness, we accept glTF 2.0's PBR
-mode, but we do so very partially, filling in a couple of reasonable constants
-for metalness and roughness and using the diffuse texture, if it exists, as the
-`base colour` texture.
+Given the command line flag --pbr-metallic-roughness, we throw ourselves into
+the warm embrace of glTF 2.0's PBR preference.
 
-More work is needed to harness the power of glTF's 2.0's materials. The biggest
-issue here is the lack of any obviously emerging standards to complement FBX
-itself. It's not clear what format an artist can export their PBR materials on,
-and when they can, how to communicate this information well to `FBX2glTF`.
+As mentioned above, there is lilttle consensus in the world on how PBR should be
+represented in FBX. At present, we support only one format: Stingray PBS. This
+is a featue that comes bundled with Maya, and any PBR model exported through
+that route should be digested propertly by FBX2glTF.
 
-(*Stingray PBS* support is
-[high on the TODO list](https://github.com/facebookincubator/FBX2glTF/issues/12).)
+(A happy note: Allegorithmic's Susbstance Painter also exports Stingray PBS,
+when hooked up to Maya.)
+
+If your model is not a Stingray PBS one, but you still wish to export PBR
+(perhaps you want to generate only core glTF wirhout reliance on extensions),
+this converter will try its best to convert your old textures. It calculates, on
+a pixel by pixel basis, reasonable values for base colour, metallicness and
+roughness, using your model's diffuse, specular, and shinines textures.
+
+It should noted here that this process cannot ever be perfect; this is very much
+an apples and oranges situation.
+
+A note of gratitude here to Gary Hsu who developed the formulae we use for this
+process. They can be eyeballed
+[here](https://github.com/KhronosGroup/glTF/blob/master/extensions/Khronos/KHR_materials_pbrSpecularGlossiness/examples/convert-between-workflows/js/three.pbrUtilities.js)
+for the curious.
 
 ## Draco Compression
 The tool will optionally apply [Draco](https://github.com/google/draco)
diff --git a/npm/package.json b/npm/package.json
index 881e248..f027a14 100644
--- a/npm/package.json
+++ b/npm/package.json
@@ -1,6 +1,6 @@
 {
   "name": "fbx2gltf",
-  "version": "0.9.2",
+  "version": "0.9.3",
   "description": "Node wrapper around FBX2glTF tools.",
   "main": "index.js",
   "repository": {
diff --git a/src/Fbx2Raw.cpp b/src/Fbx2Raw.cpp
index 62463d8..d8fafc7 100644
--- a/src/Fbx2Raw.cpp
+++ b/src/Fbx2Raw.cpp
@@ -88,46 +88,181 @@ private:
     const FbxLayerElementArrayTemplate<int>    *indices;
 };
 
-class FbxMaterialAccess
-{
-    struct FbxMaterialProperties {
-        FbxFileTexture *texAmbient {};
-        FbxVector4     colAmbient {};
-        FbxFileTexture *texSpecular {};
-        FbxVector4     colSpecular {};
-        FbxFileTexture *texDiffuse {};
-        FbxVector4     colDiffuse {};
-        FbxFileTexture *texEmissive {};
-        FbxVector4     colEmissive {};
-        FbxFileTexture *texNormal {};
-        FbxFileTexture *texShininess {};
-        FbxDouble      shininess {};
-    };
-
-private:
-    const FbxSurfaceMaterial *fbxMaterial;
-    const std::map<const FbxTexture *, FbxString> &textureLocations;
-
-public:
+struct FbxMaterialInfo {
+    FbxMaterialInfo(const FbxString &name, const FbxString &shadingModel)
+        : name(name),
+          shadingModel(shadingModel)
+    {}
     const FbxString name;
     const FbxString shadingModel;
+};
 
-    const struct FbxMaterialProperties props;
+struct FbxRoughMetMaterialInfo : FbxMaterialInfo {
+    static constexpr const char *FBX_SHADER_METROUGH = "MetallicRoughness";
 
-    explicit FbxMaterialAccess(
-        const FbxSurfaceMaterial *fbxMaterial, const std::map<const FbxTexture *, FbxString> &textureNames) :
-        fbxMaterial(fbxMaterial),
-        name(fbxMaterial->GetName()),
-        shadingModel(fbxMaterial->ShadingModel),
-        textureLocations(textureNames),
-        props(extractTextures())
+    FbxRoughMetMaterialInfo(const FbxString &name, const FbxString &shadingModel)
+        : FbxMaterialInfo(name, shadingModel)
+    {}
+    const FbxFileTexture *texColor {};
+    FbxVector4           colBase {};
+    const FbxFileTexture *texNormal {};
+    const FbxFileTexture *texMetallic {};
+    FbxDouble            metallic {};
+    const FbxFileTexture *texRoughness {};
+    FbxDouble            roughness {};
+    const FbxFileTexture *texEmissive {};
+    FbxVector4           colEmissive {};
+    FbxDouble            emissiveIntensity {};
+    const FbxFileTexture *texAmbientOcclusion {};
+
+    static std::unique_ptr<FbxRoughMetMaterialInfo> From(
+        FbxSurfaceMaterial *fbxMaterial,
+        const std::map<const FbxTexture *, FbxString> &textureLocations)
+    {
+        std::unique_ptr<FbxRoughMetMaterialInfo> res(new FbxRoughMetMaterialInfo(fbxMaterial->GetName(), FBX_SHADER_METROUGH));
+
+        const FbxProperty mayaProp = fbxMaterial->FindProperty("Maya");
+        if (mayaProp.GetPropertyDataType() != FbxCompoundDT) {
+            return nullptr;
+        }
+        if (!fbxMaterial->ShadingModel.Get().IsEmpty()) {
+            fmt::printf("Warning: Material %s has surprising shading model: %s\n",
+                fbxMaterial->GetName(), fbxMaterial->ShadingModel.Get());
+        }
+
+        auto getTex = [&](std::string propName) {
+            const FbxFileTexture *ptr = nullptr;
+
+            const FbxProperty useProp = mayaProp.FindHierarchical(("use_" + propName + "_map").c_str());
+            if (useProp.IsValid() && useProp.Get<bool>()) {
+                const FbxProperty texProp = mayaProp.FindHierarchical(("TEX_" + propName + "_map").c_str());
+                if (texProp.IsValid()) {
+                    ptr = texProp.GetSrcObject<FbxFileTexture>();
+                    if (ptr != nullptr && textureLocations.find(ptr) == textureLocations.end()) {
+                        ptr = nullptr;
+                    }
+                }
+            } else if (verboseOutput && useProp.IsValid()) {
+                fmt::printf("Note: Property '%s' of material '%s' exists, but is flagged as 'do not use'.\n",
+                    propName, fbxMaterial->GetName());
+            }
+            return ptr;
+        };
+
+        auto getVec = [&](std::string propName) -> FbxDouble3 {
+            const FbxProperty vecProp = mayaProp.FindHierarchical(propName.c_str());
+            return vecProp.IsValid() ? vecProp.Get<FbxDouble3>() : FbxDouble3(1, 1, 1);
+        };
+
+        auto getVal = [&](std::string propName) -> FbxDouble {
+            const FbxProperty vecProp = mayaProp.FindHierarchical(propName .c_str());
+            return vecProp.IsValid() ? vecProp.Get<FbxDouble>() : 0;
+        };
+
+        res->texNormal = getTex("normal");
+        res->texColor = getTex("color");
+        res->colBase = getVec("base_color");
+        res->texAmbientOcclusion = getTex("ao");
+        res->texEmissive = getTex("emissive");
+        res->colEmissive = getVec("emissive");
+        res->emissiveIntensity = getVal("emissive_intensity");
+        res->texMetallic = getTex("metallic");
+        res->metallic = getVal("metallic");
+        res->texRoughness = getTex("roughness");
+        res->roughness = getVal("roughness");
+
+        return res;
+    }
+};
+
+struct FbxTraditionalMaterialInfo : FbxMaterialInfo {
+    static constexpr const char *FBX_SHADER_LAMBERT = "Lambert";
+    static constexpr const char *FBX_SHADER_BLINN   = "Blinn";
+    static constexpr const char *FBX_SHADER_PHONG   = "Phong";
+
+    FbxTraditionalMaterialInfo(const FbxString &name, const FbxString &shadingModel)
+        : FbxMaterialInfo(name, shadingModel)
     {}
 
-    struct FbxMaterialProperties extractTextures() {
-        struct FbxMaterialProperties res;
+    FbxFileTexture *texAmbient {};
+    FbxVector4     colAmbient {};
+    FbxFileTexture *texSpecular {};
+    FbxVector4     colSpecular {};
+    FbxFileTexture *texDiffuse {};
+    FbxVector4     colDiffuse {};
+    FbxFileTexture *texEmissive {};
+    FbxVector4     colEmissive {};
+    FbxFileTexture *texNormal {};
+    FbxFileTexture *texShininess {};
+    FbxDouble      shininess {};
+
+    static std::unique_ptr<FbxTraditionalMaterialInfo> From(
+        FbxSurfaceMaterial *fbxMaterial,
+        const std::map<const FbxTexture *, FbxString> &textureLocations)
+    {
+        auto getSurfaceScalar = [&](const char *propName) -> std::tuple<FbxDouble, FbxFileTexture *> {
+            const FbxProperty prop = fbxMaterial->FindProperty(propName);
+
+            FbxDouble val(0);
+            FbxFileTexture *tex = prop.GetSrcObject<FbxFileTexture>();
+            if (tex != nullptr && textureLocations.find(tex) == textureLocations.end()) {
+                tex = nullptr;
+            }
+            if (tex == nullptr && prop.IsValid()) {
+                val = prop.Get<FbxDouble>();
+            }
+            return std::make_tuple(val, tex);
+        };
+
+        auto getSurfaceVector = [&](const char *propName) -> std::tuple<FbxDouble3, FbxFileTexture *> {
+            const FbxProperty prop = fbxMaterial->FindProperty(propName);
+
+            FbxDouble3 val(1, 1, 1);
+            FbxFileTexture *tex = prop.GetSrcObject<FbxFileTexture>();
+            if (tex != nullptr && textureLocations.find(tex) == textureLocations.end()) {
+                tex = nullptr;
+            }
+            if (tex == nullptr && prop.IsValid()) {
+                val = prop.Get<FbxDouble3>();
+            }
+            return std::make_tuple(val, tex);
+        };
+
+        auto getSurfaceValues = [&](const char *colName, const char *facName) -> std::tuple<FbxVector4, FbxFileTexture *, FbxFileTexture *> {
+            const FbxProperty colProp = fbxMaterial->FindProperty(colName);
+            const FbxProperty facProp = fbxMaterial->FindProperty(facName);
+
+            FbxDouble3 colorVal(1, 1, 1);
+            FbxDouble  factorVal(1);
+
+            FbxFileTexture *colTex = colProp.GetSrcObject<FbxFileTexture>();
+            if (colTex != nullptr && textureLocations.find(colTex) == textureLocations.end()) {
+                colTex = nullptr;
+            }
+            if (colTex == nullptr && colProp.IsValid()) {
+                colorVal = colProp.Get<FbxDouble3>();
+            }
+            FbxFileTexture *facTex = facProp.GetSrcObject<FbxFileTexture>();
+            if (facTex != nullptr && textureLocations.find(facTex) == textureLocations.end()) {
+                facTex = nullptr;
+            }
+            if (facTex == nullptr && facProp.IsValid()) {
+                factorVal = facProp.Get<FbxDouble>();
+            }
+
+            auto val = FbxVector4(
+                colorVal[0] * factorVal,
+                colorVal[1] * factorVal,
+                colorVal[2] * factorVal,
+                factorVal);
+            return std::make_tuple(val, colTex, facTex);
+        };
+
+        std::string name = fbxMaterial->GetName();
+        std::unique_ptr<FbxTraditionalMaterialInfo> res(new FbxTraditionalMaterialInfo(name.c_str(), fbxMaterial->ShadingModel.Get()));
 
         // four properties are on the same structure and follow the same rules
-        auto handleBasicProperty = [&](const char *colName, const char *facName) {
+        auto handleBasicProperty = [&](const char *colName, const char *facName) -> std::tuple<FbxVector4, FbxFileTexture *>{
             FbxFileTexture *colTex, *facTex;
             FbxVector4     vec;
 
@@ -141,20 +276,20 @@ public:
             return std::make_tuple(vec, facTex);
         };
 
-        std::tie(res.colAmbient, res.texAmbient) =
+        std::tie(res->colAmbient, res->texAmbient) =
             handleBasicProperty(FbxSurfaceMaterial::sAmbient, FbxSurfaceMaterial::sAmbientFactor);
-        std::tie(res.colSpecular, res.texSpecular) =
+        std::tie(res->colSpecular, res->texSpecular) =
             handleBasicProperty(FbxSurfaceMaterial::sSpecular, FbxSurfaceMaterial::sSpecularFactor);
-        std::tie(res.colDiffuse, res.texDiffuse) =
+        std::tie(res->colDiffuse, res->texDiffuse) =
             handleBasicProperty(FbxSurfaceMaterial::sDiffuse, FbxSurfaceMaterial::sDiffuseFactor);
-        std::tie(res.colEmissive, res.texEmissive) =
+        std::tie(res->colEmissive, res->texEmissive) =
             handleBasicProperty(FbxSurfaceMaterial::sEmissive, FbxSurfaceMaterial::sEmissiveFactor);
 
         // the normal map can only ever be a map, ignore everything else
-        std::tie(std::ignore, res.texNormal) = getSurfaceVector(FbxSurfaceMaterial::sNormalMap);
+        std::tie(std::ignore, res->texNormal) = getSurfaceVector(FbxSurfaceMaterial::sNormalMap);
 
         // shininess can be a map or a factor
-        std::tie(res.shininess, res.texShininess) = getSurfaceScalar(FbxSurfaceMaterial::sShininess);
+        std::tie(res->shininess, res->texShininess) = getSurfaceScalar(FbxSurfaceMaterial::sShininess);
 
         // for transparency we just want a constant vector value;
         FbxVector4 transparency;
@@ -169,73 +304,24 @@ public:
             fmt::printf("Warning: Mat [%s]: Can't handle texture for %s; discarding.\n", name, FbxSurfaceMaterial::sTransparencyFactor);
         }
         // FBX color is RGB, so we calculate the A channel as the average of the FBX transparency color vector
-        res.colDiffuse[3] = 1.0 - (transparency[0] + transparency[1] + transparency[2])/3.0;
+        res->colDiffuse[3] = 1.0 - (transparency[0] + transparency[1] + transparency[2])/3.0;
 
         return res;
     }
-
-    std::tuple<FbxDouble, FbxFileTexture *> getSurfaceScalar(const char *propName) const
-    {
-        const FbxProperty prop = fbxMaterial->FindProperty(propName);
-
-        FbxDouble val(0);
-        FbxFileTexture *tex = prop.GetSrcObject<FbxFileTexture>();
-        if (tex != nullptr && textureLocations.find(tex) == textureLocations.end()) {
-            tex = nullptr;
-        }
-        if (tex == nullptr && prop.IsValid()) {
-            val = prop.Get<FbxDouble>();
-        }
-        return std::make_tuple(val, tex);
-    }
-
-    std::tuple<FbxDouble3, FbxFileTexture *> getSurfaceVector(const char *propName) const
-    {
-        const FbxProperty prop = fbxMaterial->FindProperty(propName);
-
-        FbxDouble3 val(1, 1, 1);
-        FbxFileTexture *tex = prop.GetSrcObject<FbxFileTexture>();
-        if (tex != nullptr && textureLocations.find(tex) == textureLocations.end()) {
-            tex = nullptr;
-        }
-        if (tex == nullptr && prop.IsValid()) {
-            val = prop.Get<FbxDouble3>();
-        }
-        return std::make_tuple(val, tex);
-    }
-
-    std::tuple<FbxVector4, FbxFileTexture *, FbxFileTexture *> getSurfaceValues(const char *colName, const char *facName) const
-    {
-        const FbxProperty colProp = fbxMaterial->FindProperty(colName);
-        const FbxProperty facProp = fbxMaterial->FindProperty(facName);
-
-        FbxDouble3 colorVal(1, 1, 1);
-        FbxDouble  factorVal(1);
-
-        FbxFileTexture *colTex = colProp.GetSrcObject<FbxFileTexture>();
-        if (colTex != nullptr && textureLocations.find(colTex) == textureLocations.end()) {
-            colTex = nullptr;
-        }
-        if (colTex == nullptr && colProp.IsValid()) {
-            colorVal = colProp.Get<FbxDouble3>();
-        }
-        FbxFileTexture *facTex = facProp.GetSrcObject<FbxFileTexture>();
-        if (facTex != nullptr && textureLocations.find(facTex) == textureLocations.end()) {
-            facTex = nullptr;
-        }
-        if (facTex == nullptr && facProp.IsValid()) {
-            factorVal = facProp.Get<FbxDouble>();
-        }
-
-        auto val = FbxVector4(
-            colorVal[0] * factorVal,
-            colorVal[1] * factorVal,
-            colorVal[2] * factorVal,
-            factorVal);
-        return std::make_tuple(val, colTex, facTex);
-    };
 };
 
+
+std::unique_ptr<FbxMaterialInfo>
+GetMaterialInfo(FbxSurfaceMaterial *material, const std::map<const FbxTexture *, FbxString> &textureLocations)
+{
+    std::unique_ptr<FbxMaterialInfo> res;
+    res = FbxRoughMetMaterialInfo::From(material, textureLocations);
+    if (!res) {
+        res = FbxTraditionalMaterialInfo::From(material, textureLocations);
+    }
+    return res;
+}
+
 class FbxMaterialsAccess
 {
 public:
@@ -273,14 +359,14 @@ public:
             }
             auto summary = summaries[materialNum];
             if (summary == nullptr) {
-                summary = summaries[materialNum] = std::make_shared<FbxMaterialAccess>(
+                summary = summaries[materialNum] = GetMaterialInfo(
                     mesh->GetNode()->GetSrcObject<FbxSurfaceMaterial>(materialNum),
                     textureLocations);
             }
         }
     }
 
-    const std::shared_ptr<FbxMaterialAccess> GetMaterial(const int polygonIndex) const
+    const std::shared_ptr<FbxMaterialInfo> GetMaterial(const int polygonIndex) const
     {
         if (mappingMode != FbxGeometryElement::eNone) {
             const int materialNum = indices->GetAt((mappingMode == FbxGeometryElement::eByPolygon) ? polygonIndex : 0);
@@ -293,10 +379,10 @@ public:
     }
 
 private:
-    FbxGeometryElement::EMappingMode                mappingMode;
-    std::vector<std::shared_ptr<FbxMaterialAccess>> summaries {};
-    const FbxMesh                                   *mesh;
-    const FbxLayerElementArrayTemplate<int>         *indices;
+    FbxGeometryElement::EMappingMode              mappingMode;
+    std::vector<std::shared_ptr<FbxMaterialInfo>> summaries {};
+    const FbxMesh                                 *mesh;
+    const FbxLayerElementArrayTemplate<int>       *indices;
 };
 
 class FbxSkinningAccess
@@ -338,7 +424,7 @@ public:
                     inverseBindMatrices.emplace_back(globalBindposeInverseMatrix);
 
                     jointNodes.push_back(cluster->GetLink());
-                    jointNames.push_back(*cluster->GetLink()->GetName() != '\0' ? cluster->GetLink()->GetName() : cluster->GetName());
+                    jointIds.push_back(cluster->GetLink()->GetUniqueID());
 
                     const FbxAMatrix globalNodeTransform = cluster->GetLink()->EvaluateGlobalTransform();
                     jointSkinningTransforms.push_back(FbxMatrix(globalNodeTransform * globalBindposeInverseMatrix));
@@ -400,9 +486,9 @@ public:
         return jointNodes[jointIndex];
     }
 
-    const char *GetJointName(const int jointIndex) const
+    const long GetJointId(const int jointIndex) const
     {
-        return jointNames[jointIndex].c_str();
+        return jointIds[jointIndex];
     }
 
     const FbxMatrix &GetJointSkinningTransform(const int jointIndex) const
@@ -415,10 +501,10 @@ public:
         return jointInverseGlobalTransforms[jointIndex];
     }
 
-    const char *GetRootNode() const
+    const long GetRootNode() const
     {
         assert(rootIndex != -1);
-        return jointNames[rootIndex].c_str();
+        return jointIds[rootIndex];
     }
 
     const FbxAMatrix &GetInverseBindMatrix(const int jointIndex) const
@@ -440,7 +526,7 @@ public:
 
 private:
     int                      rootIndex;
-    std::vector<std::string> jointNames;
+    std::vector<long>        jointIds;
     std::vector<FbxNode *>   jointNodes;
     std::vector<FbxMatrix>   jointSkinningTransforms;
     std::vector<FbxMatrix>   jointInverseGlobalTransforms;
@@ -607,8 +693,23 @@ static void ReadMesh(RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std:
     meshConverter.Triangulate(pNode->GetNodeAttribute(), true);
     FbxMesh *pMesh = pNode->GetMesh();
 
+    // Obtains the surface Id
+    const long surfaceId = pMesh->GetUniqueID();
+
+    // Associate the node to this surface
+    int nodeId = raw.GetNodeById(pNode->GetUniqueID());
+    if (nodeId >= 0) {
+        RawNode &node = raw.GetNode(nodeId);
+        node.surfaceId = surfaceId;
+    }
+
+    if (raw.GetSurfaceById(surfaceId) >= 0) {
+        // This surface is already loaded
+        return;
+    }
+
     const char *meshName = (pNode->GetName()[0] != '\0') ? pNode->GetName() : pMesh->GetName();
-    const int rawSurfaceIndex = raw.AddSurface(meshName, pNode->GetName());
+    const int rawSurfaceIndex = raw.AddSurface(meshName, surfaceId);
 
     const FbxVector4 *controlPoints = pMesh->GetControlPoints();
     const FbxLayerElementAccess<FbxVector4> normalLayer(pMesh->GetElementNormal(), pMesh->GetElementNormalCount());
@@ -624,7 +725,7 @@ static void ReadMesh(RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std:
     if (verboseOutput) {
         fmt::printf(
             "mesh %d: %s (skinned: %s)\n", rawSurfaceIndex, meshName,
-            skinning.IsSkinned() ? skinning.GetRootNode() : "NO");
+            skinning.IsSkinned() ? raw.GetNode(raw.GetNodeById(skinning.GetRootNode())).name.c_str() : "NO");
     }
 
     // The FbxNode geometric transformation describes how a FbxNodeAttribute is offset from
@@ -638,7 +739,10 @@ static void ReadMesh(RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std:
     const FbxVector4 meshScaling               = pNode->GetGeometricScaling(FbxNode::eSourcePivot);
     const FbxAMatrix meshTransform(meshTranslation, meshRotation, meshScaling);
     const FbxMatrix  transform                 = meshTransform;
-    const FbxMatrix  inverseTransposeTransform = transform.Inverse().Transpose();
+
+    // Remove translation & scaling from transforms that will bi applied to normals, tangents & binormals
+    const FbxMatrix  normalTransform(FbxVector4(), meshRotation, meshScaling);
+    const FbxMatrix  inverseTransposeTransform = normalTransform.Inverse().Transpose();
 
     raw.AddVertexAttribute(RAW_VERTEX_ATTRIBUTE_POSITION);
     if (normalLayer.LayerPresent()) { raw.AddVertexAttribute(RAW_VERTEX_ATTRIBUTE_NORMAL); }
@@ -654,12 +758,12 @@ static void ReadMesh(RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std:
 
     RawSurface &rawSurface = raw.GetSurface(rawSurfaceIndex);
 
-    rawSurface.skeletonRootName = (skinning.IsSkinned()) ? skinning.GetRootNode() : pNode->GetName();
+    rawSurface.skeletonRootId = (skinning.IsSkinned()) ? skinning.GetRootNode() : pNode->GetUniqueID();
     for (int jointIndex = 0; jointIndex < skinning.GetNodeCount(); jointIndex++) {
-        const char *jointName = skinning.GetJointName(jointIndex);
-        raw.GetNode(raw.GetNodeByName(jointName)).isJoint = true;
+        const long jointId = skinning.GetJointId(jointIndex);
+        raw.GetNode(raw.GetNodeById(jointId)).isJoint = true;
 
-        rawSurface.jointNames.emplace_back(jointName);
+        rawSurface.jointIds.emplace_back(jointId);
         rawSurface.inverseBindMatrices.push_back(toMat4f(skinning.GetInverseBindMatrix(jointIndex)));
         rawSurface.jointGeometryMins.emplace_back(FLT_MAX, FLT_MAX, FLT_MAX);
         rawSurface.jointGeometryMaxs.emplace_back(-FLT_MAX, -FLT_MAX, -FLT_MAX);
@@ -684,27 +788,23 @@ static void ReadMesh(RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std:
 
     for (int polygonIndex = 0; polygonIndex < pMesh->GetPolygonCount(); polygonIndex++) {
         FBX_ASSERT(pMesh->GetPolygonSize(polygonIndex) == 3);
-
-        const std::shared_ptr<FbxMaterialAccess> fbxMaterial = materials.GetMaterial(polygonIndex);
+        const std::shared_ptr<FbxMaterialInfo> fbxMaterial = materials.GetMaterial(polygonIndex);
 
         int textures[RAW_TEXTURE_USAGE_MAX];
-        std::fill_n(textures, RAW_TEXTURE_USAGE_MAX, -1);
+        std::fill_n(textures, (int) RAW_TEXTURE_USAGE_MAX, -1);
 
-        FbxString  shadingModel, materialName;
-        FbxVector4 ambient, specular, diffuse, emissive;
-        FbxDouble  shininess;
+        std::shared_ptr<RawMatProps> rawMatProps;
+        FbxString materialName;
 
         if (fbxMaterial == nullptr) {
             materialName = "DefaultMaterial";
-            shadingModel = "Lambert";
+            rawMatProps.reset(new RawTraditionalMatProps(RAW_SHADING_MODEL_LAMBERT,
+                Vec3f(0, 0, 0), Vec4f(.5, .5, .5, 1), Vec3f(0, 0, 0), Vec3f(0, 0, 0), 0.5));
 
         } else {
             materialName = fbxMaterial->name;
-            shadingModel = fbxMaterial->shadingModel;
 
-            const auto &matProps = fbxMaterial->props;
-
-            const auto maybeAddTexture = [&](FbxFileTexture *tex, RawTextureUsage usage) {
+            const auto maybeAddTexture = [&](const FbxFileTexture *tex, RawTextureUsage usage) {
                 if (tex != nullptr) {
                     // dig out the inferred filename from the textureLocations map
                     FbxString inferredPath = textureLocations.find(tex)->second;
@@ -712,19 +812,44 @@ static void ReadMesh(RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std:
                 }
             };
 
-            ambient = matProps.colAmbient;
-            maybeAddTexture(matProps.texAmbient, RAW_TEXTURE_USAGE_AMBIENT);
-            specular = matProps.colSpecular;
-            maybeAddTexture(matProps.texSpecular, RAW_TEXTURE_USAGE_SPECULAR);
-            diffuse = matProps.colDiffuse;
-            maybeAddTexture(matProps.texDiffuse, RAW_TEXTURE_USAGE_DIFFUSE);
-            emissive = matProps.colEmissive;
-            maybeAddTexture(matProps.texEmissive, RAW_TEXTURE_USAGE_EMISSIVE);
+            std::shared_ptr<RawMatProps> matInfo;
+            if (fbxMaterial->shadingModel == FbxRoughMetMaterialInfo::FBX_SHADER_METROUGH) {
+                FbxRoughMetMaterialInfo *fbxMatInfo = static_cast<FbxRoughMetMaterialInfo *>(fbxMaterial.get());
 
-            maybeAddTexture(matProps.texNormal, RAW_TEXTURE_USAGE_NORMAL);
+                maybeAddTexture(fbxMatInfo->texColor, RAW_TEXTURE_USAGE_ALBEDO);
+                maybeAddTexture(fbxMatInfo->texNormal, RAW_TEXTURE_USAGE_NORMAL);
+                maybeAddTexture(fbxMatInfo->texEmissive, RAW_TEXTURE_USAGE_EMISSIVE);
+                maybeAddTexture(fbxMatInfo->texRoughness, RAW_TEXTURE_USAGE_ROUGHNESS);
+                maybeAddTexture(fbxMatInfo->texMetallic, RAW_TEXTURE_USAGE_METALLIC);
+                maybeAddTexture(fbxMatInfo->texAmbientOcclusion, RAW_TEXTURE_USAGE_OCCLUSION);
+                rawMatProps.reset(new RawMetRoughMatProps(
+                    RAW_SHADING_MODEL_PBR_MET_ROUGH, toVec4f(fbxMatInfo->colBase), toVec3f(fbxMatInfo->colEmissive),
+                    fbxMatInfo->emissiveIntensity, fbxMatInfo->metallic, fbxMatInfo->roughness));
+            } else {
 
-            shininess = matProps.shininess;
-            maybeAddTexture(matProps.texShininess, RAW_TEXTURE_USAGE_SHININESS);
+                FbxTraditionalMaterialInfo *fbxMatInfo = static_cast<FbxTraditionalMaterialInfo *>(fbxMaterial.get());
+                RawShadingModel shadingModel;
+                if (fbxMaterial->shadingModel == "Lambert") {
+                    shadingModel = RAW_SHADING_MODEL_LAMBERT;
+                } else if (fbxMaterial->shadingModel == "Blinn") {
+                    shadingModel = RAW_SHADING_MODEL_BLINN;
+                } else if (fbxMaterial->shadingModel == "Phong") {
+                    shadingModel = RAW_SHADING_MODEL_PHONG;
+                } else if (fbxMaterial->shadingModel == "Constant") {
+                    shadingModel = RAW_SHADING_MODEL_PHONG;
+                } else {
+                    shadingModel = RAW_SHADING_MODEL_UNKNOWN;
+                }
+                maybeAddTexture(fbxMatInfo->texDiffuse, RAW_TEXTURE_USAGE_DIFFUSE);
+                maybeAddTexture(fbxMatInfo->texNormal, RAW_TEXTURE_USAGE_NORMAL);
+                maybeAddTexture(fbxMatInfo->texEmissive, RAW_TEXTURE_USAGE_EMISSIVE);
+                maybeAddTexture(fbxMatInfo->texShininess, RAW_TEXTURE_USAGE_SHININESS);
+                maybeAddTexture(fbxMatInfo->texAmbient, RAW_TEXTURE_USAGE_AMBIENT);
+                maybeAddTexture(fbxMatInfo->texSpecular, RAW_TEXTURE_USAGE_SPECULAR);
+                rawMatProps.reset(new RawTraditionalMatProps(shadingModel,
+                    toVec3f(fbxMatInfo->colAmbient), toVec4f(fbxMatInfo->colDiffuse), toVec3f(fbxMatInfo->colEmissive),
+                    toVec3f(fbxMatInfo->colSpecular), fbxMatInfo->shininess));
+            }
         }
 
         RawVertex rawVertices[3];
@@ -852,9 +977,7 @@ static void ReadMesh(RawModel &raw, FbxScene *pScene, FbxNode *pNode, const std:
         }
 
         const RawMaterialType materialType = GetMaterialType(raw, textures, vertexTransparency, skinning.IsSkinned());
-        const int rawMaterialIndex = raw.AddMaterial(
-            materialName, shadingModel, materialType, textures,
-            toVec3f(ambient), toVec4f(diffuse), toVec3f(specular), toVec3f(emissive), shininess);
+        const int rawMaterialIndex = raw.AddMaterial(materialName, materialType, textures, rawMatProps);
 
         raw.AddTriangle(rawVertexIndices[0], rawVertexIndices[1], rawVertexIndices[2], rawMaterialIndex, rawSurfaceIndex);
     }
@@ -865,12 +988,12 @@ static void ReadCamera(RawModel &raw, FbxScene *pScene, FbxNode *pNode)
     const FbxCamera *pCamera = pNode->GetCamera();
     if (pCamera->ProjectionType.Get() == FbxCamera::EProjectionType::ePerspective) {
         raw.AddCameraPerspective(
-            "", pNode->GetName(), (float) pCamera->FilmAspectRatio,
+            "", pNode->GetUniqueID(), (float) pCamera->FilmAspectRatio,
             (float) pCamera->FieldOfViewX, (float) pCamera->FieldOfViewX,
             (float) pCamera->NearPlane, (float) pCamera->FarPlane);
     } else {
         raw.AddCameraOrthographic(
-            "", pNode->GetName(),
+            "", pNode->GetUniqueID(),
             (float) pCamera->OrthoZoom, (float) pCamera->OrthoZoom,
             (float) pCamera->FarPlane, (float) pCamera->NearPlane);
     }
@@ -946,10 +1069,11 @@ static FbxVector4 computeLocalScale(FbxNode *pNode, FbxTime pTime = FBXSDK_TIME_
 
 static void ReadNodeHierarchy(
     RawModel &raw, FbxScene *pScene, FbxNode *pNode,
-    const std::string &parentName, const std::string &path)
+    const long parentId, const std::string &path)
 {
+    const FbxUInt64 nodeId = pNode->GetUniqueID();
     const char *nodeName = pNode->GetName();
-    const int  nodeIndex = raw.AddNode(nodeName, parentName.c_str());
+    const int  nodeIndex = raw.AddNode(nodeId, nodeName, parentId);
     RawNode    &node     = raw.GetNode(nodeIndex);
 
     FbxTransform::EInheritType lInheritType;
@@ -962,7 +1086,7 @@ static void ReadNodeHierarchy(
 
     static int warnRrSsCount = 0;
     static int warnRrsCount  = 0;
-    if (lInheritType == FbxTransform::eInheritRrSs && !parentName.empty()) {
+    if (lInheritType == FbxTransform::eInheritRrSs && parentId) {
         if (++warnRrSsCount == 1) {
             fmt::printf("Warning: node %s uses unsupported transform inheritance type 'eInheritRrSs'.\n", newPath);
             fmt::printf("         (Further warnings of this type squelched.)\n");
@@ -989,19 +1113,19 @@ static void ReadNodeHierarchy(
     node.rotation    = toQuatf(localRotation);
     node.scale       = toVec3f(localScaling);
 
-    if (parentName.size() > 0) {
-        RawNode &parentNode = raw.GetNode(raw.GetNodeByName(parentName.c_str()));
+    if (parentId) {
+        RawNode &parentNode = raw.GetNode(raw.GetNodeById(parentId));
         // Add unique child name to the parent node.
-        if (std::find(parentNode.childNames.begin(), parentNode.childNames.end(), nodeName) == parentNode.childNames.end()) {
-            parentNode.childNames.push_back(nodeName);
+        if (std::find(parentNode.childIds.begin(), parentNode.childIds.end(), nodeId) == parentNode.childIds.end()) {
+            parentNode.childIds.push_back(nodeId);
         }
     } else {
         // If there is no parent then this is the root node.
-        raw.SetRootNode(nodeName);
+        raw.SetRootNode(nodeId);
     }
 
     for (int child = 0; child < pNode->GetChildCount(); child++) {
-        ReadNodeHierarchy(raw, pScene, pNode->GetChild(child), nodeName, newPath);
+        ReadNodeHierarchy(raw, pScene, pNode->GetChild(child), nodeId, newPath);
     }
 }
 
@@ -1057,7 +1181,7 @@ static void ReadAnimations(RawModel &raw, FbxScene *pScene)
             bool hasMorphs      = false;
 
             RawChannel channel;
-            channel.nodeIndex = raw.GetNodeByName(pNode->GetName());
+            channel.nodeIndex = raw.GetNodeById(pNode->GetUniqueID());
 
             for (FbxLongLong frameIndex = firstFrameIndex; frameIndex <= lastFrameIndex; frameIndex++) {
                 FbxTime pTime;
@@ -1300,7 +1424,7 @@ bool LoadFBXFile(RawModel &raw, const char *fbxFileName, const char *textureExte
         FbxSystemUnit::m.ConvertScene(pScene);
     }
 
-    ReadNodeHierarchy(raw, pScene, pScene->GetRootNode(), "", "");
+    ReadNodeHierarchy(raw, pScene, pScene->GetRootNode(), 0, "");
     ReadNodeAttributes(raw, pScene, pScene->GetRootNode(), textureLocations);
     ReadAnimations(raw, pScene);
 
diff --git a/src/Raw2Gltf.cpp b/src/Raw2Gltf.cpp
index 05ada4c..ed787cb 100644
--- a/src/Raw2Gltf.cpp
+++ b/src/Raw2Gltf.cpp
@@ -12,6 +12,11 @@
 #include <iostream>
 #include <fstream>
 
+#define STB_IMAGE_IMPLEMENTATION
+#include <stb_image.h>
+#define STB_IMAGE_WRITE_IMPLEMENTATION
+#include <stb_image_write.h>
+
 #include "FBX2glTF.h"
 #include "utils/String_Utils.h"
 #include "utils/Image_Utils.h"
@@ -217,13 +222,29 @@ struct GLTFData
     Holder<SceneData>      scenes;
 };
 
+static void WriteToVectorContext(void *context, void *data, int size) {
+    auto *vec = static_cast<std::vector<char> *>(context);
+    for (int ii = 0; ii < size; ii ++) {
+        vec->push_back(((char *) data)[ii]);
+    }
+}
+
 /**
  * This method sanity-checks existance and then returns a *reference* to the *Data instance
  * registered under that name. This is safe in the context of this tool, where all such data
  * classes are guaranteed to stick around for the duration of the process.
  */
 template<typename T>
-T &require(std::map<std::string, std::shared_ptr<T>> map, std::string key)
+T &require(std::map<std::string, std::shared_ptr<T>> map, const std::string &key)
+{
+    auto iter = map.find(key);
+    assert(iter != map.end());
+    T &result = *iter->second;
+    return result;
+}
+
+template<typename T>
+T &require(std::map<long, std::shared_ptr<T>> map, long key)
 {
     auto iter = map.find(key);
     assert(iter != map.end());
@@ -260,7 +281,7 @@ ModelData *Raw2Gltf(
         for (int i = 0; i < raw.GetMaterialCount(); i++) {
             fmt::printf(
                 "Material %d: %s [shading: %s]\n", i, raw.GetMaterial(i).name.c_str(),
-                raw.GetMaterial(i).shadingModel.c_str());
+                Describe(raw.GetMaterial(i).info->shadingModel));
         }
         if (raw.GetVertexCount() > 2 * raw.GetTriangleCount()) {
             fmt::printf(
@@ -282,9 +303,10 @@ ModelData *Raw2Gltf(
 
     std::unique_ptr<GLTFData> gltf(new GLTFData(options.outputBinary));
 
-    std::map<std::string, std::shared_ptr<NodeData>>     nodesByName;
+    std::map<long, std::shared_ptr<NodeData>>            nodesById;
     std::map<std::string, std::shared_ptr<MaterialData>> materialsByName;
-    std::map<std::string, std::shared_ptr<MeshData>>     meshByNodeName;
+    std::map<std::string, std::shared_ptr<TextureData>>  textureByIndicesKey;
+    std::map<long, std::shared_ptr<MeshData>>            meshBySurfaceId;
 
     // for now, we only have one buffer; data->binary points to the same vector as that BufferData does.
     BufferData &buffer = *gltf->buffers.hold(
@@ -303,13 +325,13 @@ ModelData *Raw2Gltf(
             auto nodeData = gltf->nodes.hold(
                 new NodeData(node.name, node.translation, node.rotation, node.scale, node.isJoint));
 
-            for (const auto &childName : node.childNames) {
-                int childIx = raw.GetNodeByName(childName.c_str());
+            for (const auto &childId : node.childIds) {
+                int childIx = raw.GetNodeById(childId);
                 assert(childIx >= 0);
                 nodeData->AddChildNode(childIx);
             }
-            assert(nodesByName.find(nodeData->name) == nodesByName.end());
-            nodesByName.insert(std::make_pair(nodeData->name, nodeData));
+            
+            nodesById.insert(std::make_pair(node.id, nodeData));
         }
 
         //
@@ -344,7 +366,7 @@ ModelData *Raw2Gltf(
                         channel.scales.size(), channel.weights.size());
                 }
 
-                NodeData &nDat = require(nodesByName, node.name);
+                NodeData &nDat = require(nodesById, node.id);
                 if (!channel.translations.empty()) {
                     aDat.AddNodeChannel(nDat, *gltf->AddAccessorAndView(buffer, GLT_VEC3F, channel.translations), "translation");
                 }
@@ -370,23 +392,204 @@ ModelData *Raw2Gltf(
         // textures
         //
 
-        for (int textureIndex = 0; textureIndex < raw.GetTextureCount(); textureIndex++) {
-            const RawTexture  &texture         = raw.GetTexture(textureIndex);
-            const std::string textureName      = Gltf::StringUtils::GetFileBaseString(texture.name);
-            const std::string relativeFilename = Gltf::StringUtils::GetFileNameString(texture.fileLocation);
+        using pixel = std::array<float, 4>; // pixel components are floats in [0, 1]
+        using pixel_merger = std::function<pixel(const std::vector<const pixel *>)>;
 
-            ImageData *source = nullptr;
+        auto texIndicesKey = [&](std::vector<int> ixVec, std::string tag) -> std::string {
+            std::string result = tag;
+            for (int ix : ixVec) {
+                result += "_" + std::to_string(ix);
+            }
+            return result;
+        };
+
+        /**
+         * Create a new derived TextureData for the two given RawTexture indexes, or return a previously created one.
+         * Each pixel in the derived texture will be determined from its equivalent in each source pixels, as decided
+         * by the provided `combine` function.
+         */
+        auto getDerivedTexture = [&](
+            std::vector<int> rawTexIndices,
+            const pixel_merger &combine,
+            const std::string &tag,
+            bool transparentOutput
+        ) -> std::shared_ptr<TextureData>
+        {
+            const std::string key = texIndicesKey(rawTexIndices, tag);
+            auto iter = textureByIndicesKey.find(key);
+            if (iter != textureByIndicesKey.end()) {
+                return iter->second;
+            }
+
+            auto describeChannel = [&](int channels) -> std::string {
+                switch(channels) {
+                    case 1: return "G";
+                    case 2: return "GA";
+                    case 3: return "RGB";
+                    case 4: return "RGBA";
+                    default:
+                        return fmt::format("?%d?", channels);
+                }
+            };
+
+            // keep track of some texture data as we load them
+            struct TexInfo {
+                explicit TexInfo(int rawTexIx) : rawTexIx(rawTexIx) {}
+
+                const int rawTexIx;
+                int width {};
+                int height {};
+                int channels {};
+                uint8_t *pixels {};
+            };
+
+            int width = -1, height = -1;
+            std::string mergedName = tag;
+            std::string mergedFilename = tag;
+            std::vector<TexInfo> texes { };
+            for (const int rawTexIx : rawTexIndices) {
+                TexInfo info(rawTexIx);
+                if (rawTexIx >= 0) {
+                    const RawTexture &rawTex = raw.GetTexture(rawTexIx);
+                    const std::string &fileLoc = rawTex.fileLocation;
+                    const std::string &fileLocBase = Gltf::StringUtils::GetFileBaseString(Gltf::StringUtils::GetFileNameString(fileLoc));
+                    if (!fileLoc.empty()) {
+                        info.pixels = stbi_load(fileLoc.c_str(), &info.width, &info.height, &info.channels, 0);
+                        if (!info.pixels) {
+                            fmt::printf("Warning: merge texture [%d](%s) could not be loaded.\n",
+                                rawTexIx,
+                                Gltf::StringUtils::GetFileBaseString(Gltf::StringUtils::GetFileNameString(fileLoc)));
+                        } else {
+                            if (width < 0) {
+                                width = info.width;
+                                height = info.height;
+                            } else if (width != info.width || height != info.height) {
+                                fmt::printf("Warning: texture %s (%d, %d) can't be merged with previous texture(s) of dimension (%d, %d)\n",
+                                    Gltf::StringUtils::GetFileBaseString(Gltf::StringUtils::GetFileNameString(fileLoc)),
+                                    info.width, info.height, width, height);
+                                // this is bad enough that we abort the whole merge
+                                return nullptr;
+                            }
+                            mergedName += "_" + rawTex.fileName;
+                            mergedFilename += "_" + fileLocBase;
+                        }
+                    }
+                }
+                texes.push_back(info);
+            }
+
+            if (width < 0) {
+                // no textures to merge; bail
+                return nullptr;
+            }
+            // TODO: which channel combinations make sense in input files?
+
+            // write 3 or 4 channels depending on whether or not we need transparency
+            int channels = transparentOutput ? 4 : 3;
+
+            std::vector<uint8_t> mergedPixels(static_cast<size_t>(channels * width * height));
+            std::vector<pixel> pixels(texes.size());
+            std::vector<const pixel *> pixelPointers(texes.size());
+            for (int xx = 0; xx < width; xx ++) {
+                for (int yy = 0; yy < height; yy ++) {
+                    pixels.clear();
+                    for (int jj = 0; jj < texes.size(); jj ++) {
+                        const TexInfo &tex = texes[jj];
+                        // each texture's structure will depend on its channel count
+                        int ii = tex.channels * (xx + yy*width);
+                        int kk = 0;
+                        if (tex.pixels != nullptr) {
+                            for (; kk < tex.channels; kk ++) {
+                                pixels[jj][kk] = tex.pixels[ii++] / 255.0f;
+                            }
+                        }
+                        for (; kk < pixels[jj].size(); kk ++) {
+                            pixels[jj][kk] = 1.0f;
+                        }
+                        pixelPointers[jj] = &pixels[jj];
+                    }
+                    const pixel merged = combine(pixelPointers);
+                    int ii = channels * (xx + yy*width);
+                    for (int jj = 0; jj < channels; jj ++) {
+                        mergedPixels[ii + jj] = static_cast<uint8_t>(fmax(0, fmin(255.0f, merged[jj] * 255.0f)));
+                    }
+                }
+            }
+
+            // write a .png iff we need transparency in the destination texture
+            bool png = transparentOutput;
+
+            std::vector<char> imgBuffer;
+            int res;
+            if (png) {
+                res = stbi_write_png_to_func(WriteToVectorContext, &imgBuffer,
+                    width, height, channels, mergedPixels.data(), width * channels);
+            } else {
+                res = stbi_write_jpg_to_func(WriteToVectorContext, &imgBuffer,
+                    width, height, channels, mergedPixels.data(), 80);
+            }
+            if (!res) {
+                fmt::printf("Warning: failed to generate merge texture '%s'.\n", mergedFilename);
+                return nullptr;
+            }
+
+            ImageData *image;
             if (options.outputBinary) {
-                auto bufferView = gltf->AddBufferViewForFile(buffer, texture.fileLocation);
+                const auto bufferView = gltf->AddRawBufferView(buffer, imgBuffer.data(), imgBuffer.size());
+                image = new ImageData(mergedName, *bufferView, png ? "image/png" : "image/jpeg");
+
+            } else {
+                const std::string imageFilename = mergedFilename + (png ? ".png" : ".jpg");
+                const std::string imagePath = outputFolder + imageFilename;
+                FILE *fp = fopen(imagePath.c_str(), "wb");
+                if (fp == nullptr) {
+                    fmt::printf("Warning:: Couldn't write file '%s' for writing.\n", imagePath);
+                    return nullptr;
+                }
+
+                if (fwrite(imgBuffer.data(), imgBuffer.size(), 1, fp) != 1) {
+                    fmt::printf("Warning: Failed to write %lu bytes to file '%s'.\n", imgBuffer.size(), imagePath);
+                    fclose(fp);
+                    return nullptr;
+                }
+                fclose(fp);
+                if (verboseOutput) {
+                    fmt::printf("Wrote %lu bytes to texture '%s'.\n", imgBuffer.size(), imagePath);
+                }
+
+                image = new ImageData(mergedName, imageFilename);
+            }
+
+            std::shared_ptr<TextureData> texDat = gltf->textures.hold(
+                new TextureData(mergedName, defaultSampler, *gltf->images.hold(image)));
+            textureByIndicesKey.insert(std::make_pair(key, texDat));
+            return texDat;
+        };
+
+        /** Create a new TextureData for the given RawTexture index, or return a previously created one. */
+        auto getSimpleTexture = [&](int rawTexIndex, const std::string &tag) {
+            const std::string key = texIndicesKey({ rawTexIndex }, tag);
+            auto iter = textureByIndicesKey.find(key);
+            if (iter != textureByIndicesKey.end()) {
+                return iter->second;
+            }
+
+            const RawTexture  &rawTexture      = raw.GetTexture(rawTexIndex);
+            const std::string textureName      = Gltf::StringUtils::GetFileBaseString(rawTexture.name);
+            const std::string relativeFilename = Gltf::StringUtils::GetFileNameString(rawTexture.fileLocation);
+
+            ImageData *image = nullptr;
+            if (options.outputBinary) {
+                auto bufferView = gltf->AddBufferViewForFile(buffer, rawTexture.fileLocation);
                 if (bufferView) {
-                    std::string suffix = Gltf::StringUtils::GetFileSuffixString(texture.fileLocation);
-                    source = new ImageData(relativeFilename, *bufferView, suffixToMimeType(suffix));
+                    std::string suffix = Gltf::StringUtils::GetFileSuffixString(rawTexture.fileLocation);
+                    image = new ImageData(relativeFilename, *bufferView, suffixToMimeType(suffix));
                 }
 
             } else if (!relativeFilename.empty()) {
-                source = new ImageData(relativeFilename, relativeFilename);
+                image = new ImageData(relativeFilename, relativeFilename);
                 std::string outputPath = outputFolder + relativeFilename;
-                if (FileUtils::CopyFile(texture.fileLocation, outputPath)) {
+                if (FileUtils::CopyFile(rawTexture.fileLocation, outputPath)) {
                     if (verboseOutput) {
                         fmt::printf("Copied texture '%s' to output folder: %s\n", textureName, outputPath);
                     }
@@ -396,15 +599,16 @@ ModelData *Raw2Gltf(
                     // reference, even if the copy failed.
                 }
             }
-            if (!source) {
+            if (!image) {
                 // fallback is tiny transparent gif
-                source = new ImageData(textureName, "data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs=");
+                image = new ImageData(textureName, "data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs=");
             }
 
-            const TextureData &texDat = *gltf->textures.hold(
-                new TextureData(textureName, defaultSampler, *gltf->images.hold(source)));
-            assert(texDat.ix == textureIndex);
-        }
+            std::shared_ptr<TextureData> texDat = gltf->textures.hold(
+                new TextureData(textureName, defaultSampler, *gltf->images.hold(image)));
+            textureByIndicesKey.insert(std::make_pair(key, texDat));
+            return texDat;
+        };
 
         //
         // materials
@@ -416,42 +620,290 @@ ModelData *Raw2Gltf(
                            material.type == RAW_MATERIAL_TYPE_TRANSPARENT ||
                            material.type == RAW_MATERIAL_TYPE_SKINNED_TRANSPARENT;
 
-            // find a texture by usage and return it as a TextureData*, or nullptr if none exists.
-            auto getTex = [&](RawTextureUsage usage)
-            {
-                // note that we depend on TextureData.ix == rawTexture's index
-                return (material.textures[usage] >= 0) ? gltf->textures.ptrs[material.textures[usage]].get() : nullptr;
+            Vec3f emissiveFactor;
+            float emissiveIntensity;
+
+            const Vec3f dielectric(0.04f, 0.04f, 0.04f);
+            const float epsilon = 1e-6f;
+
+            // acquire the texture of a specific RawTextureUsage as *TextData, or nullptr if none exists
+            auto simpleTex = [&](RawTextureUsage usage) -> std::shared_ptr<TextureData> {
+                return (material.textures[usage] >= 0) ? getSimpleTexture(material.textures[usage], "simple") : nullptr;
+            };
+
+            // acquire derived texture of two RawTextureUsage as *TextData, or nullptr if neither exists
+            auto merge2Tex = [&](
+                const std::string tag,
+                RawTextureUsage u1,
+                RawTextureUsage u2,
+                const pixel_merger &combine,
+                bool outputHasAlpha
+            ) -> std::shared_ptr<TextureData> {
+                return getDerivedTexture(
+                    { material.textures[u1], material.textures[u2] },
+                    combine, tag, outputHasAlpha);
+            };
+
+            // acquire derived texture of two RawTextureUsage as *TextData, or nullptr if neither exists
+            auto merge3Tex = [&](
+                const std::string tag,
+                RawTextureUsage u1,
+                RawTextureUsage u2,
+                RawTextureUsage u3,
+                const pixel_merger &combine,
+                bool outputHasAlpha
+            ) -> std::shared_ptr<TextureData> {
+                return getDerivedTexture(
+                    { material.textures[u1], material.textures[u2], material.textures[u3] },
+                    combine, tag, outputHasAlpha);
+            };
+
+            auto getMaxComponent = [&](const Vec3f &color) {
+                return fmax(color.x, fmax(color.y, color.z));
+            };
+            auto getPerceivedBrightness = [&](const Vec3f &color) {
+                return sqrt(0.299 * color.x * color.x + 0.587 * color.y * color.y + 0.114 * color.z * color.z);
+            };
+            auto toVec3f = [&](const pixel &pix) -> const Vec3f {
+                return Vec3f(pix[0], pix[1], pix[2]);
+            };
+            auto toVec4f = [&](const pixel &pix) -> const Vec4f {
+                return Vec4f(pix[0], pix[1], pix[2], pix[3]);
             };
 
             std::shared_ptr<PBRMetallicRoughness> pbrMetRough;
             if (options.usePBRMetRough) {
-                pbrMetRough.reset(new PBRMetallicRoughness(getTex(RAW_TEXTURE_USAGE_DIFFUSE), material.diffuseFactor));
+                // albedo is a basic texture, no merging needed
+                std::shared_ptr<TextureData> baseColorTex, metRoughTex;
+
+                Vec4f diffuseFactor;
+                float metallic, roughness;
+                if (material.info->shadingModel == RAW_SHADING_MODEL_PBR_MET_ROUGH) {
+                    /**
+                     * PBR FBX Material -> PBR Met/Rough glTF.
+                     *
+                     * METALLIC and ROUGHNESS textures are packed in G and B channels of a rough/met texture.
+                     * Other values translate directly.
+                     */
+                    RawMetRoughMatProps *props = (RawMetRoughMatProps *) material.info.get();
+                    // merge metallic into the blue channel and roughness into the green, of a new combinatory texture
+                    metRoughTex = merge2Tex("met_rough",
+                        RAW_TEXTURE_USAGE_METALLIC, RAW_TEXTURE_USAGE_ROUGHNESS,
+                        [&](const std::vector<const pixel *> pixels) -> pixel { return { 0, (*pixels[1])[0], (*pixels[0])[0], 0 }; },
+                        false);
+                    baseColorTex      = simpleTex(RAW_TEXTURE_USAGE_ALBEDO);
+                    diffuseFactor     = props->diffuseFactor;
+                    metallic          = props->metallic;
+                    roughness         = props->roughness;
+                    emissiveFactor    = props->emissiveFactor;
+                    emissiveIntensity = props->emissiveIntensity;
+                } else {
+                    /**
+                     * Traditional FBX Material -> PBR Met/Rough glTF.
+                     *
+                     * Diffuse channel is used as base colour. No metallic/roughness texture is attempted. Constant
+                     * metallic/roughness values are hard-coded.
+                     *
+                     * TODO: If we have specular & optional shininess map, we can generate a reasonable rough/met map.
+                     */
+                    const RawTraditionalMatProps *props = ((RawTraditionalMatProps *) material.info.get());
+                    diffuseFactor = props->diffuseFactor;
+                    // TODO: make configurable on the command line, or do a better job guessing from other, supplied params
+                    if (material.info->shadingModel == RAW_SHADING_MODEL_LAMBERT) {
+                        metallic  = 0.6f;
+                        roughness = 1.0f;
+                    } else {
+                        metallic  = 0.2f;
+                        roughness = 0.6f;
+                    }
+                    auto solveMetallic = [&](float pDiff, float pSpec, float oneMinusSpecularStrength)
+                    {
+                        if (pSpec < dielectric.x) {
+                            return 0.0;
+                        }
+
+                        float a = dielectric.x;
+                        float b = pDiff * oneMinusSpecularStrength / (1 - dielectric.x) + pSpec - 2 * dielectric.x;
+                        float c = dielectric.x - pSpec;
+                        float D = fmax(b * b - 4 * a * c, 0);
+                        return fmax(0.0, fmin(1.0, (-b + sqrt(D)) / (2 * a)));
+                    };
+                    metRoughTex = merge3Tex("rough_met",
+                        RAW_TEXTURE_USAGE_SPECULAR, RAW_TEXTURE_USAGE_SHININESS, RAW_TEXTURE_USAGE_DIFFUSE,
+                        [&](const std::vector<const pixel *> pixels) -> pixel {
+                            const Vec3f specular = pixels[0] ? toVec3f(*pixels[0]) : props->specularFactor;
+                            float shininess = pixels[1] ? (*pixels[1])[0] : props->shininess;
+                            const Vec4f diffuse = pixels[2] ? toVec4f(*pixels[2]) : props->diffuseFactor;
+
+                            float pixelMet = solveMetallic(
+                                getPerceivedBrightness(diffuse.xyz()),
+                                getPerceivedBrightness(specular),
+                                1 - getMaxComponent(specular));
+                            float pixelRough = 1 - shininess;
+
+                            return { 0, pixelRough, pixelMet, 0 };
+                    }, false);
+                    if (material.textures[RAW_TEXTURE_USAGE_DIFFUSE] >= 0) {
+                        const RawTexture &diffuseTex = raw.GetTexture(material.textures[RAW_TEXTURE_USAGE_DIFFUSE]);
+                        baseColorTex = merge2Tex("base_col", RAW_TEXTURE_USAGE_DIFFUSE, RAW_TEXTURE_USAGE_SPECULAR,
+                        [&](const std::vector<const pixel *> pixels) -> pixel {
+                            const Vec4f diffuse = pixels[0] ? toVec4f(*pixels[0]) : props->diffuseFactor;
+                            const Vec3f specular = pixels[1] ? toVec3f(*pixels[1]) : props->specularFactor;
+
+                            float oneMinus = 1 - getMaxComponent(specular);
+
+                            float pixelMet = solveMetallic(
+                                getPerceivedBrightness(diffuse.xyz()),
+                                getPerceivedBrightness(specular),
+                                oneMinus);
+
+                            Vec3f fromDiffuse = diffuse.xyz() * (oneMinus / (1.0f - dielectric.x) / fmax(1.0f - pixelMet, epsilon));
+                            Vec3f fromSpecular = specular - dielectric * (1.0f - pixelMet) * (1.0f / fmax(pixelMet, epsilon));
+                            Vec3f baseColor = Vec3f::Lerp(fromDiffuse, fromSpecular, pixelMet * pixelMet);
+
+                            return { baseColor[0], baseColor[1], baseColor[2], diffuse[3] };
+                        }, diffuseTex.occlusion == RAW_TEXTURE_OCCLUSION_TRANSPARENT);
+                    }
+                    emissiveFactor    = props->emissiveFactor;
+                    emissiveIntensity = 1.0f;
+                }
+                pbrMetRough.reset(new PBRMetallicRoughness(baseColorTex.get(), metRoughTex.get(), diffuseFactor, metallic, roughness));
             }
+
             std::shared_ptr<PBRSpecularGlossiness> pbrSpecGloss;
             if (options.usePBRSpecGloss) {
+                Vec4f                        diffuseFactor;
+                Vec3f                        specularFactor;
+                float                        glossiness;
+                std::shared_ptr<TextureData> specGlossTex;
+                std::shared_ptr<TextureData> diffuseTex;
+
+                const Vec3f dielectric(0.04f, 0.04f, 0.04f);
+                const float epsilon = 1e-6f;
+                if (material.info->shadingModel == RAW_SHADING_MODEL_PBR_MET_ROUGH) {
+                    /**
+                     * PBR FBX Material -> PBR Spec/Gloss glTF.
+                     *
+                     * TODO: A complete mess. Low priority.
+                     */
+                    RawMetRoughMatProps *props = (RawMetRoughMatProps *) material.info.get();
+                    // we can estimate spec/gloss from met/rough by between Vec4f(0.04, 0.04, 0.04) and baseColor
+                    // according to metalness, and then taking gloss to be the inverse of roughness
+                    specGlossTex = merge3Tex("specgloss",
+                        RAW_TEXTURE_USAGE_ALBEDO, RAW_TEXTURE_USAGE_METALLIC, RAW_TEXTURE_USAGE_ROUGHNESS,
+                        [&](const std::vector<const pixel *> pixels) -> pixel {
+                            Vec3f baseColor(1.0f);
+                            if (pixels[0]) {
+                                baseColor.x = (*pixels[0])[0];
+                                baseColor.y = (*pixels[0])[1];
+                                baseColor.z = (*pixels[0])[2];
+                            }
+                            float metallic = pixels[1] ? (*pixels[1])[0] : 1.0f;
+                            float roughness = pixels[2] ? (*pixels[2])[0] : 1.0f;
+                            Vec3f spec = Vec3f::Lerp(dielectric, baseColor, metallic);
+                            return { spec[0], spec[1], spec[2], 1.0f - roughness };
+                         }, false);
+                    diffuseTex = merge2Tex("albedo",
+                        RAW_TEXTURE_USAGE_ALBEDO, RAW_TEXTURE_USAGE_METALLIC,
+                        [&](const std::vector<const pixel *> pixels) -> pixel {
+                            Vec3f baseColor(1.0f);
+                            float alpha = 1.0f;
+                            if (pixels[0]) {
+                                baseColor[0] = (*pixels[0])[0];
+                                baseColor[1] = (*pixels[0])[1];
+                                baseColor[2] = (*pixels[0])[2];
+                                alpha = (*pixels[0])[3];
+                            }
+                            float metallic = pixels[1] ? (*pixels[1])[0] : 1.0f;
+                            Vec3f spec = Vec3f::Lerp(dielectric, baseColor, metallic);
+                            float maxSpecComp = fmax(fmax(spec.x, spec.y), spec.z);
+                            // attenuate baseColor to get specgloss-compliant diffuse; for details consult
+                            // https://github.com/KhronosGroup/glTF/tree/master/extensions/Khronos/KHR_materials_pbrSpecularGlossiness
+                            Vec3f diffuse = baseColor * (1 - dielectric[0]) * (1 - metallic) * fmax(1.0f - maxSpecComp, epsilon);
+                            return { diffuse[0], diffuse[1], diffuse[2], alpha };
+                         }, true);
+                    diffuseFactor = props->diffuseFactor;
+                    specularFactor = Vec3f::Lerp(dielectric, props->diffuseFactor.xyz(), props->metallic);
+                    glossiness = 1.0f - props->roughness;
+
+                } else {
+                    /**
+                     * Traditional FBX Material -> PBR Spec/Gloss glTF.
+                     *
+                     * TODO: A complete mess. Low priority.
+                     */
+                    // TODO: this section a ludicrous over-simplifictation; we can surely do better.
+                    const RawTraditionalMatProps *props = ((RawTraditionalMatProps *) material.info.get());
+                    specGlossTex = merge2Tex("specgloss",
+                        RAW_TEXTURE_USAGE_SPECULAR, RAW_TEXTURE_USAGE_SHININESS,
+                        [&](const std::vector<const pixel *> pixels) -> pixel {
+                            const auto &spec = *(pixels[0]);
+                            const auto &shine = *(pixels[1]);
+                            return { spec[0], spec[1], spec[2], shine[0] };
+                        }, false);
+                    diffuseTex = simpleTex(RAW_TEXTURE_USAGE_DIFFUSE);
+                    diffuseFactor = props->diffuseFactor;
+                    specularFactor = props->specularFactor;
+                    glossiness = props->shininess;
+                }
+
                 pbrSpecGloss.reset(
                     new PBRSpecularGlossiness(
-                        getTex(RAW_TEXTURE_USAGE_DIFFUSE), material.diffuseFactor,
-                        getTex(RAW_TEXTURE_USAGE_SPECULAR), material.specularFactor, material.shininess));
+                        diffuseTex.get(), diffuseFactor, specGlossTex.get(), specularFactor, glossiness));
             }
 
             std::shared_ptr<KHRCommonMats> khrComMat;
             if (options.useKHRMatCom) {
-                auto type = KHRCommonMats::MaterialType::Constant;
-                if (material.shadingModel == "Lambert") {
-                    type = KHRCommonMats::MaterialType::Lambert;
-                } else if (material.shadingModel == "Blinn") {
-                    type = KHRCommonMats::MaterialType::Blinn;
-                } else if (material.shadingModel == "Phong") {
-                    type = KHRCommonMats::MaterialType::Phong;
+                float                        shininess;
+                Vec3f                        ambientFactor, specularFactor;
+                Vec4f                        diffuseFactor;
+                std::shared_ptr<TextureData> diffuseTex;
+                auto                         type = KHRCommonMats::MaterialType::Constant;
+
+                if (material.info->shadingModel == RAW_SHADING_MODEL_PBR_MET_ROUGH) {
+                    /**
+                     * PBR FBX Material -> KHR Common Materials glTF.
+                     *
+                     * TODO: We can use the specularFactor calculation below to generate a reasonable specular map, too.
+                     */
+                    const RawMetRoughMatProps *props = (RawMetRoughMatProps *) material.info.get();
+                    shininess = 1.0f - props->roughness;
+                    ambientFactor = Vec3f(0.0f, 0.0f, 0.0f);
+                    diffuseTex = simpleTex(RAW_TEXTURE_USAGE_ALBEDO);
+                    diffuseFactor = props->diffuseFactor;
+                    specularFactor = Vec3f::Lerp(Vec3f(0.04f, 0.04f, 0.04f), props->diffuseFactor.xyz(), props->metallic);
+                    // render as Phong if there's any specularity, otherwise Lambert
+                    type = (specularFactor.LengthSquared() > 1e-4) ?
+                        KHRCommonMats::MaterialType::Phong : KHRCommonMats::MaterialType::Lambert;
+                    // TODO: convert textures
+
+                } else {
+                    /**
+                     * Traditional FBX Material -> KHR Common Materials glTF.
+                     *
+                     * Should be in good shape. Essentially pass-through.
+                     */
+                    const RawTraditionalMatProps *props = (RawTraditionalMatProps *) material.info.get();
+                    shininess = props->shininess;
+                    ambientFactor = props->ambientFactor;
+                    diffuseTex = simpleTex(RAW_TEXTURE_USAGE_DIFFUSE);
+                    diffuseFactor = props->diffuseFactor;
+                    specularFactor = props->specularFactor;
+
+                    if (material.info->shadingModel == RAW_SHADING_MODEL_LAMBERT) {
+                        type = KHRCommonMats::MaterialType::Lambert;
+                    } else if (material.info->shadingModel == RAW_SHADING_MODEL_BLINN) {
+                        type = KHRCommonMats::MaterialType::Blinn;
+                    } else if (material.info->shadingModel == RAW_SHADING_MODEL_PHONG) {
+                        type = KHRCommonMats::MaterialType::Phong;
+                    }
                 }
                 khrComMat.reset(
-                    new KHRCommonMats(
-                        type,
-                        getTex(RAW_TEXTURE_USAGE_SHININESS), material.shininess,
-                        getTex(RAW_TEXTURE_USAGE_AMBIENT), material.ambientFactor,
-                        getTex(RAW_TEXTURE_USAGE_DIFFUSE), material.diffuseFactor,
-                        getTex(RAW_TEXTURE_USAGE_SPECULAR), material.specularFactor));
+                    new KHRCommonMats(type,
+                        simpleTex(RAW_TEXTURE_USAGE_SHININESS).get(), shininess,
+                        simpleTex(RAW_TEXTURE_USAGE_AMBIENT).get(), ambientFactor,
+                        diffuseTex.get(), diffuseFactor,
+                        simpleTex(RAW_TEXTURE_USAGE_SPECULAR).get(), specularFactor));
             }
 
             std::shared_ptr<KHRCmnConstantMaterial> khrCmnConstantMat;
@@ -464,38 +916,27 @@ ModelData *Raw2Gltf(
 
             std::shared_ptr<MaterialData> mData = gltf->materials.hold(
                 new MaterialData(
-                    material.name, isTransparent, getTex(RAW_TEXTURE_USAGE_NORMAL),
-                    getTex(RAW_TEXTURE_USAGE_EMISSIVE), material.emissiveFactor,
+                    material.name, isTransparent,
+                    simpleTex(RAW_TEXTURE_USAGE_NORMAL).get(), simpleTex(RAW_TEXTURE_USAGE_EMISSIVE).get(),
+                    emissiveFactor * emissiveIntensity,
                     khrComMat, khrCmnConstantMat, pbrMetRough, pbrSpecGloss));
             materialsByName[materialHash(material)] = mData;
         }
 
-        //
-        // surfaces
-        //
-
-        // in GLTF 2.0, the structural limitation is that a node can
-        // only belong to a single mesh. A mesh can however contain any
-        // number of primitives, which are essentially little meshes.
-        //
-        // so each RawSurface turns into a primitive, and we sort them
-        // by root node using this map; one mesh per node.
-
         for (size_t surfaceIndex = 0; surfaceIndex < materialModels.size(); surfaceIndex++) {
             const RawModel &surfaceModel = materialModels[surfaceIndex];
 
             assert(surfaceModel.GetSurfaceCount() == 1);
             const RawSurface  &rawSurface = surfaceModel.GetSurface(0);
+            const int surfaceId = rawSurface.id;
 
             const RawMaterial &rawMaterial = surfaceModel.GetMaterial(surfaceModel.GetTriangle(0).materialIndex);
             const MaterialData &mData = require(materialsByName, materialHash(rawMaterial));
 
-            std::string nodeName  = rawSurface.nodeName;
-            NodeData    &meshNode = require(nodesByName, nodeName);
 
-            MeshData *mesh    = nullptr;
-            auto     meshIter = meshByNodeName.find(nodeName);
-            if (meshIter != meshByNodeName.end()) {
+            MeshData *mesh = nullptr;
+            auto meshIter = meshBySurfaceId.find(surfaceId);
+            if (meshIter != meshBySurfaceId.end()) {
                 mesh = meshIter->second.get();
 
             } else {
@@ -504,36 +945,10 @@ ModelData *Raw2Gltf(
                     defaultDeforms.push_back(channel.defaultDeform);
                 }
                 auto meshPtr = gltf->meshes.hold(new MeshData(rawSurface.name, defaultDeforms));
-                meshByNodeName[nodeName] = meshPtr;
-                meshNode.SetMesh(meshPtr->ix);
+                meshBySurfaceId[surfaceId] = meshPtr;
                 mesh = meshPtr.get();
             }
 
-            //
-            // surface skin
-            //
-            if (!rawSurface.jointNames.empty()) {
-                if (meshNode.skin == -1) {
-                    // glTF uses column-major matrices
-                    std::vector<Mat4f> inverseBindMatrices;
-                    for (const auto &inverseBindMatrice : rawSurface.inverseBindMatrices) {
-                        inverseBindMatrices.push_back(inverseBindMatrice.Transpose());
-                    }
-
-                    std::vector<uint32_t> jointIndexes;
-                    for (const auto &jointName : rawSurface.jointNames) {
-                        jointIndexes.push_back(require(nodesByName, jointName).ix);
-                    }
-
-                    // Write out inverseBindMatrices
-                    auto accIBM = gltf->AddAccessorAndView(buffer, GLT_MAT4F, inverseBindMatrices);
-
-                    auto skeletonRoot = require(nodesByName, rawSurface.skeletonRootName);
-                    auto skin         = *gltf->skins.hold(new SkinData(jointIndexes, *accIBM, skeletonRoot));
-                    meshNode.SetSkin(skin.ix);
-                }
-            }
-
             std::shared_ptr<PrimitiveData> primitive;
             if (options.useDraco) {
                 int triangleCount = surfaceModel.GetTriangleCount();
@@ -674,6 +1089,53 @@ ModelData *Raw2Gltf(
             mesh->AddPrimitive(primitive);
         }
 
+        //
+        // Assign meshes to node
+        //
+
+        for (int i = 0; i < raw.GetNodeCount(); i++) {
+
+            const RawNode &node = raw.GetNode(i);
+            auto nodeData = gltf->nodes.ptrs[i];
+
+            //
+            // Assign mesh to node
+            //
+            if (node.surfaceId > 0)
+            {
+                int surfaceIndex = raw.GetSurfaceById(node.surfaceId);
+                const RawSurface &rawSurface = raw.GetSurface(surfaceIndex);
+
+                MeshData &meshData = require(meshBySurfaceId, rawSurface.id);
+                nodeData->SetMesh(meshData.ix);
+
+                //
+                // surface skin
+                //
+                if (!rawSurface.jointIds.empty()) {
+                    if (nodeData->skin == -1) {
+                        // glTF uses column-major matrices
+                        std::vector<Mat4f> inverseBindMatrices;
+                        for (const auto &inverseBindMatrice : rawSurface.inverseBindMatrices) {
+                            inverseBindMatrices.push_back(inverseBindMatrice.Transpose());
+                        }
+
+                        std::vector<uint32_t> jointIndexes;
+                        for (const auto &jointId : rawSurface.jointIds) {
+                            jointIndexes.push_back(require(nodesById, jointId).ix);
+                        }
+
+                        // Write out inverseBindMatrices
+                        auto accIBM = gltf->AddAccessorAndView(buffer, GLT_MAT4F, inverseBindMatrices);
+
+                        auto skeletonRoot = require(nodesById, rawSurface.skeletonRootId);
+                        auto skin = *gltf->skins.hold(new SkinData(jointIndexes, *accIBM, skeletonRoot));
+                        nodeData->SetSkin(skin.ix);
+                    }
+                }
+            }
+        }
+
         //
         // cameras
         //
@@ -698,16 +1160,16 @@ ModelData *Raw2Gltf(
             }
             // Add the camera to the node hierarchy.
 
-            auto iter = nodesByName.find(cam.nodeName);
-            if (iter == nodesByName.end()) {
-                fmt::printf("Warning: Camera node name %s does not exist.\n", cam.nodeName);
+            auto iter = nodesById.find(cam.nodeId);
+            if (iter == nodesById.end()) {
+                fmt::printf("Warning: Camera node id %s does not exist.\n", cam.nodeId);
                 continue;
             }
-            iter->second->AddCamera(cam.name);
+            iter->second->SetCamera(camera.ix);
         }
     }
 
-    NodeData        &rootNode  = require(nodesByName, "RootNode");
+    NodeData        &rootNode  = require(nodesById, raw.GetRootNode());
     const SceneData &rootScene = *gltf->scenes.hold(new SceneData(defaultSceneName, rootNode));
 
     if (options.outputBinary) {
diff --git a/src/RawModel.cpp b/src/RawModel.cpp
index 22084c2..98eb337 100644
--- a/src/RawModel.cpp
+++ b/src/RawModel.cpp
@@ -111,35 +111,25 @@ int RawModel::AddTexture(const std::string &name, const std::string &fileName, c
 
 int RawModel::AddMaterial(const RawMaterial &material)
 {
-    return AddMaterial(
-        material.name.c_str(), material.shadingModel.c_str(), material.type, material.textures, material.ambientFactor,
-        material.diffuseFactor, material.specularFactor, material.emissiveFactor, material.shininess);
+    return AddMaterial(material.name.c_str(), material.type, material.textures, material.info);
 }
 
 int RawModel::AddMaterial(
-    const char *name, const char *shadingModel, const RawMaterialType materialType,
-    const int textures[RAW_TEXTURE_USAGE_MAX], const Vec3f ambientFactor,
-    const Vec4f diffuseFactor, const Vec3f specularFactor,
-    const Vec3f emissiveFactor, float shinineness)
+    const char *name,
+    const RawMaterialType materialType,
+    const int textures[RAW_TEXTURE_USAGE_MAX],
+    std::shared_ptr<RawMatProps> materialInfo)
 {
     for (size_t i = 0; i < materials.size(); i++) {
         if (materials[i].name != name) {
             continue;
         }
-        if (materials[i].shadingModel != shadingModel) {
-            continue;
-        }
         if (materials[i].type != materialType) {
             continue;
         }
-        if (materials[i].ambientFactor != ambientFactor ||
-            materials[i].diffuseFactor != diffuseFactor ||
-            materials[i].specularFactor != specularFactor ||
-            materials[i].emissiveFactor != emissiveFactor ||
-            materials[i].shininess != shinineness) {
+        if (*(materials[i].info) != *materialInfo) {
             continue;
         }
-
         bool match = true;
         for (int j = 0; match && j < RAW_TEXTURE_USAGE_MAX; j++) {
             match = match && (materials[i].textures[j] == textures[j]);
@@ -150,14 +140,9 @@ int RawModel::AddMaterial(
     }
 
     RawMaterial material;
-    material.name           = name;
-    material.shadingModel   = shadingModel;
-    material.type           = materialType;
-    material.ambientFactor  = ambientFactor;
-    material.diffuseFactor  = diffuseFactor;
-    material.specularFactor = specularFactor;
-    material.emissiveFactor = emissiveFactor;
-    material.shininess      = shinineness;
+    material.name = name;
+    material.type = materialType;
+    material.info = materialInfo;
 
     for (int i = 0; i < RAW_TEXTURE_USAGE_MAX; i++) {
         material.textures[i] = textures[i];
@@ -180,18 +165,18 @@ int RawModel::AddSurface(const RawSurface &surface)
     return (int) (surfaces.size() - 1);
 }
 
-int RawModel::AddSurface(const char *name, const char *nodeName)
+int RawModel::AddSurface(const char *name, const long surfaceId)
 {
     assert(name[0] != '\0');
 
     for (size_t i = 0; i < surfaces.size(); i++) {
-        if (Gltf::StringUtils::CompareNoCase(surfaces[i].name, name) == 0) {
+        if (surfaces[i].id == surfaceId) {
             return (int) i;
         }
     }
     RawSurface  surface;
+    surface.id = surfaceId;
     surface.name     = name;
-    surface.nodeName = nodeName;
     surface.bounds.Clear();
     surface.discrete  = false;
 
@@ -208,8 +193,8 @@ int RawModel::AddAnimation(const RawAnimation &animation)
 int RawModel::AddNode(const RawNode &node)
 {
     for (size_t i = 0; i < nodes.size(); i++) {
-        if (Gltf::StringUtils::CompareNoCase(nodes[i].name.c_str(), node.name) == 0) {
-            return (int) i;
+        if (nodes[i].id == node.id) {
+            return (int)i;
         }
     }
 
@@ -218,12 +203,12 @@ int RawModel::AddNode(const RawNode &node)
 }
 
 int RawModel::AddCameraPerspective(
-    const char *name, const char *nodeName, const float aspectRatio, const float fovDegreesX, const float fovDegreesY, const float nearZ,
+    const char *name, const long nodeId, const float aspectRatio, const float fovDegreesX, const float fovDegreesY, const float nearZ,
     const float farZ)
 {
     RawCamera camera;
     camera.name                    = name;
-    camera.nodeName                = nodeName;
+    camera.nodeId                  = nodeId;
     camera.mode                    = RawCamera::CAMERA_MODE_PERSPECTIVE;
     camera.perspective.aspectRatio = aspectRatio;
     camera.perspective.fovDegreesX = fovDegreesX;
@@ -235,11 +220,11 @@ int RawModel::AddCameraPerspective(
 }
 
 int RawModel::AddCameraOrthographic(
-    const char *name, const char *nodeName, const float magX, const float magY, const float nearZ, const float farZ)
+    const char *name, const long nodeId, const float magX, const float magY, const float nearZ, const float farZ)
 {
     RawCamera camera;
     camera.name               = name;
-    camera.nodeName           = nodeName;
+    camera.nodeId             = nodeId;
     camera.mode               = RawCamera::CAMERA_MODE_ORTHOGRAPHIC;
     camera.orthographic.magX  = magX;
     camera.orthographic.magY  = magY;
@@ -249,20 +234,22 @@ int RawModel::AddCameraOrthographic(
     return (int) cameras.size() - 1;
 }
 
-int RawModel::AddNode(const char *name, const char *parentName)
+int RawModel::AddNode(const long id, const char *name, const long parentId)
 {
     assert(name[0] != '\0');
 
     for (size_t i = 0; i < nodes.size(); i++) {
-        if (Gltf::StringUtils::CompareNoCase(nodes[i].name, name) == 0) {
+        if (nodes[i].id == id ) {
             return (int) i;
         }
     }
 
     RawNode joint;
     joint.isJoint     = false;
+    joint.id          = id;
     joint.name        = name;
-    joint.parentName  = parentName;
+    joint.parentId    = parentId;
+    joint.surfaceId   = 0;
     joint.translation = Vec3f(0, 0, 0);
     joint.rotation    = Quatf(0, 0, 0, 1);
     joint.scale       = Vec3f(1, 1, 1);
@@ -281,7 +268,7 @@ void RawModel::Condense()
 
         for (auto &triangle : triangles) {
             const RawSurface &surface     = oldSurfaces[triangle.surfaceIndex];
-            const int        surfaceIndex = AddSurface(surface.name.c_str(), surface.nodeName.c_str());
+            const int        surfaceIndex = AddSurface(surface.name.c_str(), surface.id);
             surfaces[surfaceIndex] = surface;
             triangle.surfaceIndex = surfaceIndex;
         }
@@ -469,9 +456,9 @@ void RawModel::CreateMaterialModels(
         RawSurface &rawSurface = model->GetSurface(surfaceIndex);
 
         if (model->GetSurfaceCount() > prevSurfaceCount) {
-            const std::vector<std::string> &jointNames = surfaces[sortedTriangles[i].surfaceIndex].jointNames;
-            for (const auto &jointName : jointNames) {
-                const int nodeIndex = GetNodeByName(jointName.c_str());
+            const std::vector<long> &jointIds = surfaces[sortedTriangles[i].surfaceIndex].jointIds;
+            for (const auto &jointId : jointIds) {
+                const int nodeIndex = GetNodeById(jointId);
                 assert(nodeIndex != -1);
                 model->AddNode(GetNode(nodeIndex));
             }
@@ -529,12 +516,22 @@ void RawModel::CreateMaterialModels(
     }
 }
 
-int RawModel::GetNodeByName(const char *name) const
+int RawModel::GetNodeById(const long nodeId) const
 {
     for (size_t i = 0; i < nodes.size(); i++) {
-        if (nodes[i].name == name) {
+        if (nodes[i].id == nodeId) {
             return (int) i;
         }
     }
     return -1;
 }
+
+int RawModel::GetSurfaceById(const long surfaceId) const
+{
+    for (size_t i = 0; i < surfaces.size(); i++) {
+        if (surfaces[i].id == surfaceId) {
+            return (int)i;
+        }
+    }
+    return -1;
+}
diff --git a/src/RawModel.h b/src/RawModel.h
index 1d0961f..1a2c6c4 100644
--- a/src/RawModel.h
+++ b/src/RawModel.h
@@ -95,8 +95,32 @@ struct RawTriangle
     int surfaceIndex;
 };
 
+enum RawShadingModel
+{
+    RAW_SHADING_MODEL_UNKNOWN = -1,
+    RAW_SHADING_MODEL_CONSTANT,
+    RAW_SHADING_MODEL_LAMBERT,
+    RAW_SHADING_MODEL_BLINN,
+    RAW_SHADING_MODEL_PHONG,
+    RAW_SHADING_MODEL_PBR_MET_ROUGH,
+    RAW_SHADING_MODEL_MAX
+};
+
+static inline std::string Describe(RawShadingModel model) {
+    switch(model) {
+        case RAW_SHADING_MODEL_UNKNOWN:         return "<unknown>";
+        case RAW_SHADING_MODEL_CONSTANT:        return "Constant";
+        case RAW_SHADING_MODEL_LAMBERT:         return "Lambert";
+        case RAW_SHADING_MODEL_BLINN:           return "Blinn";
+        case RAW_SHADING_MODEL_PHONG:           return "Phong";
+        case RAW_SHADING_MODEL_PBR_MET_ROUGH:   return "Metallic/Roughness";
+        case RAW_SHADING_MODEL_MAX: default:    return "<unknown>";
+    }
+}
+
 enum RawTextureUsage
 {
+    RAW_TEXTURE_USAGE_NONE = -1,
     RAW_TEXTURE_USAGE_AMBIENT,
     RAW_TEXTURE_USAGE_DIFFUSE,
     RAW_TEXTURE_USAGE_NORMAL,
@@ -104,32 +128,28 @@ enum RawTextureUsage
     RAW_TEXTURE_USAGE_SHININESS,
     RAW_TEXTURE_USAGE_EMISSIVE,
     RAW_TEXTURE_USAGE_REFLECTION,
+    RAW_TEXTURE_USAGE_ALBEDO,
+    RAW_TEXTURE_USAGE_OCCLUSION,
+    RAW_TEXTURE_USAGE_ROUGHNESS,
+    RAW_TEXTURE_USAGE_METALLIC,
     RAW_TEXTURE_USAGE_MAX
 };
 
-inline std::string DescribeTextureUsage(int usage)
+static inline std::string Describe(RawTextureUsage usage)
 {
-    if (usage < 0) {
-        return "<none>";
-    }
-    switch (static_cast<RawTextureUsage>(usage)) {
-        case RAW_TEXTURE_USAGE_AMBIENT:
-            return "ambient";
-        case RAW_TEXTURE_USAGE_DIFFUSE:
-            return "diffuse";
-        case RAW_TEXTURE_USAGE_NORMAL:
-            return "normal";
-        case RAW_TEXTURE_USAGE_SPECULAR:
-            return "specuar";
-        case RAW_TEXTURE_USAGE_SHININESS:
-            return "shininess";
-        case RAW_TEXTURE_USAGE_EMISSIVE:
-            return "emissive";
-        case RAW_TEXTURE_USAGE_REFLECTION:
-            return "reflection";
-        case RAW_TEXTURE_USAGE_MAX:
-        default:
-            return "unknown";
+    switch (usage) {
+        case RAW_TEXTURE_USAGE_NONE:        return "<none>";
+        case RAW_TEXTURE_USAGE_AMBIENT:     return "ambient";
+        case RAW_TEXTURE_USAGE_DIFFUSE:     return "diffuse";
+        case RAW_TEXTURE_USAGE_NORMAL:      return "normal";
+        case RAW_TEXTURE_USAGE_SPECULAR:    return "specuar";
+        case RAW_TEXTURE_USAGE_SHININESS:   return "shininess";
+        case RAW_TEXTURE_USAGE_EMISSIVE:    return "emissive";
+        case RAW_TEXTURE_USAGE_REFLECTION:  return "reflection";
+        case RAW_TEXTURE_USAGE_OCCLUSION:   return "occlusion";
+        case RAW_TEXTURE_USAGE_ROUGHNESS:   return "roughness";
+        case RAW_TEXTURE_USAGE_METALLIC:    return "metallic";
+        case RAW_TEXTURE_USAGE_MAX:default: return "unknown";
     }
 };
 
@@ -159,18 +179,91 @@ enum RawMaterialType
     RAW_MATERIAL_TYPE_SKINNED_TRANSPARENT,
 };
 
+struct RawMatProps {
+    explicit RawMatProps(RawShadingModel shadingModel)
+        : shadingModel(shadingModel)
+    {}
+    const RawShadingModel shadingModel;
+
+    virtual bool operator!=(const RawMatProps &other) const { return !(*this == other); }
+    virtual bool operator==(const RawMatProps &other) const { return shadingModel == other.shadingModel; };
+};
+
+struct RawTraditionalMatProps : RawMatProps {
+    RawTraditionalMatProps(
+        RawShadingModel shadingModel,
+        const Vec3f &&ambientFactor,
+        const Vec4f &&diffuseFactor,
+        const Vec3f &&emissiveFactor,
+        const Vec3f &&specularFactor,
+        const float shininess
+    ) : RawMatProps(shadingModel),
+          ambientFactor(ambientFactor),
+          diffuseFactor(diffuseFactor),
+          emissiveFactor(emissiveFactor),
+          specularFactor(specularFactor),
+          shininess(shininess)
+    {}
+
+    const Vec3f ambientFactor;
+    const Vec4f diffuseFactor;
+    const Vec3f emissiveFactor;
+    const Vec3f specularFactor;
+    const float shininess;
+
+    bool operator==(const RawMatProps &other) const override {
+        if (RawMatProps::operator==(other)) {
+            const auto &typed = (RawTraditionalMatProps &) other;
+            return ambientFactor == typed.ambientFactor &&
+                diffuseFactor == typed.diffuseFactor &&
+                specularFactor == typed.specularFactor &&
+                emissiveFactor == typed.emissiveFactor &&
+                shininess == typed.shininess;
+        }
+        return false;
+    }
+};
+
+struct RawMetRoughMatProps : RawMatProps {
+    RawMetRoughMatProps(
+        RawShadingModel shadingModel,
+        const Vec4f &&diffuseFactor,
+        const Vec3f &&emissiveFactor,
+        float emissiveIntensity,
+        float metallic,
+        float roughness
+    ) : RawMatProps(shadingModel),
+      diffuseFactor(diffuseFactor),
+      emissiveFactor(emissiveFactor),
+      emissiveIntensity(emissiveIntensity),
+      metallic(metallic),
+      roughness(roughness)
+    {}
+    const Vec4f diffuseFactor;
+    const Vec3f emissiveFactor;
+    const float emissiveIntensity;
+    const float metallic;
+    const float roughness;
+
+    bool operator==(const RawMatProps &other) const override {
+        if (RawMatProps::operator==(other)) {
+            const auto &typed = (RawMetRoughMatProps &) other;
+            return diffuseFactor == typed.diffuseFactor &&
+            emissiveFactor == typed.emissiveFactor &&
+            emissiveIntensity == typed.emissiveIntensity &&
+            metallic == typed.metallic &&
+            roughness == typed.roughness;
+        }
+        return false;
+    }
+};
+
 struct RawMaterial
 {
-
-    std::string     name;
-    std::string     shadingModel;    // typically "Surface", "Anisotropic", "Blinn", "Lambert", "Phong", "Phone E"
-    RawMaterialType type;
-    Vec3f           ambientFactor;
-    Vec4f           diffuseFactor;
-    Vec3f           specularFactor;
-    Vec3f           emissiveFactor;
-    float           shininess;
-    int             textures[RAW_TEXTURE_USAGE_MAX];
+    std::string                  name;
+    RawMaterialType              type;
+    std::shared_ptr<RawMatProps> info;
+    int                          textures[RAW_TEXTURE_USAGE_MAX];
 };
 
 struct RawBlendChannel
@@ -182,11 +275,11 @@ struct RawBlendChannel
 
 struct RawSurface
 {
+    long                         id;
     std::string                  name;                            // The name of this surface
-    std::string                  nodeName;                        // The node that links to this surface.
-    std::string                  skeletonRootName;                // The name of the root of the skeleton.
+    long                         skeletonRootId;                  // The id of the root node of the skeleton.
     Bounds<float, 3>             bounds;
-    std::vector<std::string>     jointNames;
+    std::vector<long>            jointIds;
     std::vector<Vec3f>           jointGeometryMins;
     std::vector<Vec3f>           jointGeometryMaxs;
     std::vector<Mat4f>           inverseBindMatrices;
@@ -213,7 +306,7 @@ struct RawAnimation
 struct RawCamera
 {
     std::string name;
-    std::string nodeName;
+    long        nodeId;
 
     enum
     {
@@ -242,12 +335,14 @@ struct RawCamera
 struct RawNode
 {
     bool                     isJoint;
+    long                     id;
     std::string              name;
-    std::string              parentName;
-    std::vector<std::string> childNames;
+    long                     parentId;
+    std::vector<long>        childIds;
     Vec3f                    translation;
     Quatf                    rotation;
     Vec3f                    scale;
+    long                     surfaceId;
 };
 
 class RawModel
@@ -262,22 +357,20 @@ public:
     int AddTexture(const std::string &name, const std::string &fileName, const std::string &fileLocation, RawTextureUsage usage);
     int AddMaterial(const RawMaterial &material);
     int AddMaterial(
-        const char *name, const char *shadingModel, RawMaterialType materialType,
-        const int textures[RAW_TEXTURE_USAGE_MAX], Vec3f ambientFactor,
-        Vec4f diffuseFactor, Vec3f specularFactor,
-        Vec3f emissiveFactor, float shinineness);
+        const char *name, const RawMaterialType materialType, const int textures[RAW_TEXTURE_USAGE_MAX],
+        std::shared_ptr<RawMatProps> materialInfo);
     int AddSurface(const RawSurface &suface);
-    int AddSurface(const char *name, const char *nodeName);
+    int AddSurface(const char *name, long surfaceId);
     int AddAnimation(const RawAnimation &animation);
     int AddCameraPerspective(
-        const char *name, const char *nodeName, const float aspectRatio, const float fovDegreesX, const float fovDegreesY,
+        const char *name, const long nodeId, const float aspectRatio, const float fovDegreesX, const float fovDegreesY,
         const float nearZ, const float farZ);
     int
-    AddCameraOrthographic(const char *name, const char *nodeName, const float magX, const float magY, const float nearZ, const float farZ);
+    AddCameraOrthographic(const char *name, const long nodeId, const float magX, const float magY, const float nearZ, const float farZ);
     int AddNode(const RawNode &node);
-    int AddNode(const char *name, const char *parentName);
-    void SetRootNode(const char *name) { rootNodeName = name; }
-    const char *GetRootNode() const { return rootNodeName.c_str(); }
+    int AddNode(const long id, const char *name, const long parentId);
+    void SetRootNode(const long nodeId) { rootNodeId = nodeId; }
+    const long GetRootNode() const { return rootNodeId; }
 
     // Remove unused vertices, textures or materials after removing vertex attributes, textures, materials or surfaces.
     void Condense();
@@ -307,6 +400,7 @@ public:
     int GetSurfaceCount() const { return (int) surfaces.size(); }
     const RawSurface &GetSurface(const int index) const { return surfaces[index]; }
     RawSurface &GetSurface(const int index) { return surfaces[index]; }
+    int GetSurfaceById(const long id) const;
 
     // Iterate over the animations.
     int GetAnimationCount() const { return (int) animations.size(); }
@@ -320,7 +414,7 @@ public:
     int GetNodeCount() const { return (int) nodes.size(); }
     const RawNode &GetNode(const int index) const { return nodes[index]; }
     RawNode &GetNode(const int index) { return nodes[index]; }
-    int GetNodeByName(const char *name) const;
+    int GetNodeById(const long nodeId) const;
 
     // Create individual attribute arrays.
     // Returns true if the vertices store the particular attribute.
@@ -334,7 +428,7 @@ public:
         std::vector<RawModel> &materialModels, const int maxModelVertices, const int keepAttribs, const bool forceDiscrete) const;
 
 private:
-    std::string                                      rootNodeName;
+    long                                             rootNodeId;
     int                                              vertexAttributes;
     std::unordered_map<RawVertex, int, VertexHasher> vertexHash;
     std::vector<RawVertex>                           vertices;
diff --git a/src/glTF/MaterialData.cpp b/src/glTF/MaterialData.cpp
index 853ae70..01d489e 100644
--- a/src/glTF/MaterialData.cpp
+++ b/src/glTF/MaterialData.cpp
@@ -135,10 +135,11 @@ void to_json(json &j, const PBRSpecularGlossiness &d)
 }
 
 PBRMetallicRoughness::PBRMetallicRoughness(
-    const TextureData *baseColorTexture, const Vec4f &baseolorFactor,
-    float metallic, float roughness)
+    const TextureData *baseColorTexture, const TextureData *metRoughTexture,
+    const Vec4f &baseColorFactor, float metallic, float roughness)
     : baseColorTexture(Tex::ref(baseColorTexture)),
-      baseColorFactor(baseolorFactor),
+      metRoughTexture(Tex::ref(metRoughTexture)),
+      baseColorFactor(baseColorFactor),
       metallic(metallic),
       roughness(roughness)
 {
@@ -153,10 +154,14 @@ void to_json(json &j, const PBRMetallicRoughness &d)
     if (d.baseColorFactor.LengthSquared() > 0) {
         j["baseColorFactor"] = toStdVec(d.baseColorFactor);
     }
-    if (d.metallic != 1.0f) {
+    if (d.metRoughTexture != nullptr) {
+        j["metallicRoughnessTexture"] = *d.metRoughTexture;
+        // if a texture is provided, throw away metallic/roughness values
+        j["roughnessFactor"] = 1.0f;
+        j["metallicFactor"] = 1.0f;
+    } else {
+        // without a texture, however, use metallic/roughness as constants
         j["metallicFactor"] = d.metallic;
-    }
-    if (d.roughness != 1.0f) {
         j["roughnessFactor"] = d.roughness;
     }
 }
diff --git a/src/glTF/MaterialData.h b/src/glTF/MaterialData.h
index b4bcbdb..448d94e 100644
--- a/src/glTF/MaterialData.h
+++ b/src/glTF/MaterialData.h
@@ -75,10 +75,11 @@ struct PBRSpecularGlossiness
 struct PBRMetallicRoughness
 {
     PBRMetallicRoughness(
-        const TextureData *baseColorTexture, const Vec4f &baseolorFactor,
-        float metallic = 0.1f, float roughness = 0.4f);
+        const TextureData *baseColorTexture, const TextureData *metRoughTexture,
+        const Vec4f &baseColorFactor, float metallic = 0.1f, float roughness = 0.6f);
 
     std::unique_ptr<Tex> baseColorTexture;
+    std::unique_ptr<Tex> metRoughTexture;
     const Vec4f          baseColorFactor;
     const float          metallic;
     const float          roughness;
diff --git a/src/glTF/NodeData.cpp b/src/glTF/NodeData.cpp
index f4a3efd..5e9cfb4 100644
--- a/src/glTF/NodeData.cpp
+++ b/src/glTF/NodeData.cpp
@@ -20,7 +20,7 @@ NodeData::NodeData(
       scale(scale),
       children(),
       mesh(-1),
-      cameraName(""),
+      camera(-1),
       skin(-1)
 {
 }
@@ -44,10 +44,10 @@ void NodeData::SetSkin(uint32_t skinIx)
     skin = skinIx;
 }
 
-void NodeData::AddCamera(std::string camera)
+void NodeData::SetCamera(uint32_t cameraIndex)
 {
     assert(!isJoint);
-    cameraName = std::move(camera);
+    camera = cameraIndex;
 }
 
 json NodeData::serialize() const
@@ -75,8 +75,8 @@ json NodeData::serialize() const
         if (skin >= 0) {
             result["skin"] = skin;
         }
-        if (!cameraName.empty()) {
-            result["camera"] = cameraName;
+        if (camera >= 0) {
+            result["camera"] = camera;
         }
     }
     return result;
diff --git a/src/glTF/NodeData.h b/src/glTF/NodeData.h
index cd78acb..6fdd2e7 100644
--- a/src/glTF/NodeData.h
+++ b/src/glTF/NodeData.h
@@ -19,7 +19,7 @@ struct NodeData : Holdable
     void AddChildNode(uint32_t childIx);
     void SetMesh(uint32_t meshIx);
     void SetSkin(uint32_t skinIx);
-    void AddCamera(std::string camera);
+    void SetCamera(uint32_t camera);
 
     json serialize() const override;
 
@@ -30,7 +30,7 @@ struct NodeData : Holdable
     Vec3f                    scale;
     std::vector<uint32_t>    children;
     int32_t                  mesh;
-    std::string              cameraName;
+    int32_t                  camera;
     int32_t                  skin;
     std::vector<std::string> skeletons;
 };