3p-package-source/package-system/assimp/usd_animations-on-top-of-v5.4.3.patch

diff --git a/code/AssetLib/USD/USDLoaderImplTinyusdz.cpp b/code/AssetLib/USD/USDLoaderImplTinyusdz.cpp
index 3e32917f9..b4fd6a51b 100644
--- a/code/AssetLib/USD/USDLoaderImplTinyusdz.cpp
+++ b/code/AssetLib/USD/USDLoaderImplTinyusdz.cpp
@@ -58,6 +58,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <assimp/importerdesc.h>
 #include <assimp/IOStreamBuffer.h>
 #include <assimp/IOSystem.hpp>
+#include "assimp/MemoryIOWrapper.h"
 #include <assimp/StringUtils.h>
 #include <assimp/StreamReader.h>
 
@@ -81,7 +82,7 @@ using namespace std;
 void USDImporterImplTinyusdz::InternReadFile(
         const std::string &pFile,
         aiScene *pScene,
-        IOSystem *) {
+        IOSystem *pIOHandler) {
     // Grab filename for logging purposes
     size_t pos = pFile.find_last_of('/');
     string basePath = pFile.substr(0, pos);
@@ -91,29 +92,48 @@ void USDImporterImplTinyusdz::InternReadFile(
     ss << "InternReadFile(): model" << nameWExt;
     TINYUSDZLOGD(TAG, "%s", ss.str().c_str());
 
+    bool is_load_from_mem{ pFile.substr(0, AI_MEMORYIO_MAGIC_FILENAME_LENGTH) == AI_MEMORYIO_MAGIC_FILENAME };
+    std::vector<uint8_t> in_mem_data;
+    if (is_load_from_mem) {
+        auto stream_closer = [pIOHandler](IOStream *pStream) {
+            pIOHandler->Close(pStream);
+        };
+        std::unique_ptr<IOStream, decltype(stream_closer)> file_stream(pIOHandler->Open(pFile, "rb"), stream_closer);
+        if (!file_stream) {
+            throw DeadlyImportError("Failed to open file ", pFile, ".");
+        }
+        size_t file_size{ file_stream->FileSize() };
+        in_mem_data.resize(file_size);
+        file_stream->Read(in_mem_data.data(), 1, file_size);
+    }
+
     bool ret{ false };
     tinyusdz::USDLoadOptions options;
     tinyusdz::Stage stage;
     std::string warn, err;
     bool is_usdz{ false };
     if (isUsdc(pFile)) {
-        ret = LoadUSDCFromFile(pFile, &stage, &warn, &err, options);
+        ret = is_load_from_mem ? LoadUSDCFromMemory(in_mem_data.data(), in_mem_data.size(), pFile, &stage, &warn, &err, options) :
+                                 LoadUSDCFromFile(pFile, &stage, &warn, &err, options);
         ss.str("");
         ss << "InternReadFile(): LoadUSDCFromFile() result: " << ret;
         TINYUSDZLOGD(TAG, "%s", ss.str().c_str());
     } else if (isUsda(pFile)) {
-        ret = LoadUSDAFromFile(pFile, &stage, &warn, &err, options);
+        ret = is_load_from_mem ? LoadUSDAFromMemory(in_mem_data.data(), in_mem_data.size(), pFile, &stage, &warn, &err, options) :
+                                 LoadUSDAFromFile(pFile, &stage, &warn, &err, options);
         ss.str("");
         ss << "InternReadFile(): LoadUSDAFromFile() result: " << ret;
         TINYUSDZLOGD(TAG, "%s", ss.str().c_str());
     } else if (isUsdz(pFile)) {
-        ret = LoadUSDZFromFile(pFile, &stage, &warn, &err, options);
+        ret = is_load_from_mem ? LoadUSDZFromMemory(in_mem_data.data(), in_mem_data.size(), pFile, &stage, &warn, &err, options) :
+                                 LoadUSDZFromFile(pFile, &stage, &warn, &err, options);
         is_usdz = true;
         ss.str("");
         ss << "InternReadFile(): LoadUSDZFromFile() result: " << ret;
         TINYUSDZLOGD(TAG, "%s", ss.str().c_str());
     } else if (isUsd(pFile)) {
-        ret = LoadUSDFromFile(pFile, &stage, &warn, &err, options);
+        ret = is_load_from_mem ? LoadUSDFromMemory(in_mem_data.data(), in_mem_data.size(), pFile, &stage, &warn, &err, options) :
+                                 LoadUSDFromFile(pFile, &stage, &warn, &err, options);
         ss.str("");
         ss << "InternReadFile(): LoadUSDFromFile() result: " << ret;
         TINYUSDZLOGD(TAG, "%s", ss.str().c_str());
@@ -149,7 +169,9 @@ void USDImporterImplTinyusdz::InternReadFile(
     // NOTE: Pointer address of usdz_asset must be valid until the call of RenderSceneConverter::ConvertToRenderScene.
     tinyusdz::USDZAsset usdz_asset;
     if (is_usdz) {
-        if (!tinyusdz::ReadUSDZAssetInfoFromFile(pFile, &usdz_asset, &warn, &err)) {
+        bool is_read_USDZ_asset = is_load_from_mem ? tinyusdz::ReadUSDZAssetInfoFromMemory(in_mem_data.data(), in_mem_data.size(), false, &usdz_asset, &warn, &err) :
+                                                     tinyusdz::ReadUSDZAssetInfoFromFile(pFile, &usdz_asset, &warn, &err);
+        if (!is_read_USDZ_asset) {
             if (!warn.empty()) {
                 ss.str("");
                 ss << "InternReadFile(): ReadUSDZAssetInfoFromFile: WARNING reported: " << warn;
@@ -190,18 +212,140 @@ void USDImporterImplTinyusdz::InternReadFile(
         return;
     }
 
-//    sanityCheckNodesRecursive(pScene->mRootNode);
+    // sanityCheckNodesRecursive(pScene->mRootNode);
+    animations(render_scene, pScene);
     meshes(render_scene, pScene, nameWExt);
     materials(render_scene, pScene, nameWExt);
     textures(render_scene, pScene, nameWExt);
     textureImages(render_scene, pScene, nameWExt);
     buffers(render_scene, pScene, nameWExt);
-
-    std::map<size_t, tinyusdz::tydra::Node> meshNodes;
-    setupNodes(render_scene, pScene, meshNodes, nameWExt);
+    pScene->mRootNode = nodesRecursive(nullptr, render_scene.nodes[0], render_scene.skeletons);
 
     setupBlendShapes(render_scene, pScene, nameWExt);
 }
+void USDImporterImplTinyusdz::animations(
+    const tinyusdz::tydra::RenderScene& render_scene,
+    aiScene* pScene) {
+    if (render_scene.animations.empty()) {
+        return;
+    }
+
+    pScene->mNumAnimations = render_scene.animations.size();
+    pScene->mAnimations = new aiAnimation *[pScene->mNumAnimations];
+
+    for (int animationIndex = 0; animationIndex < pScene->mNumAnimations; ++animationIndex) {
+
+        const auto &animation = render_scene.animations[animationIndex];
+
+        auto newAiAnimation = new aiAnimation();
+        pScene->mAnimations[animationIndex] = newAiAnimation;
+
+        newAiAnimation->mName = animation.abs_path;
+
+        if (animation.channels_map.empty()) {
+            newAiAnimation->mNumChannels = 0;
+            continue;
+        }
+
+        // each channel affects a node (joint)
+        newAiAnimation->mTicksPerSecond = render_scene.meta.framesPerSecond;
+        newAiAnimation->mNumChannels = animation.channels_map.size();
+        newAiAnimation->mChannels = new aiNodeAnim *[newAiAnimation->mNumChannels];
+        int channelIndex = 0;
+        for (const auto &[jointName, animationChannelMap] : animation.channels_map) {
+            auto newAiNodeAnim = new aiNodeAnim();
+            newAiAnimation->mChannels[channelIndex] = newAiNodeAnim;
+            newAiNodeAnim->mNodeName = jointName;
+            newAiAnimation->mDuration = 0;
+
+            std::vector<aiVectorKey> positionKeys;
+            std::vector<aiQuatKey> rotationKeys;
+            std::vector<aiVectorKey> scalingKeys;
+
+            for (const auto &[channelType, animChannel] : animationChannelMap) {
+                switch (channelType) {
+                case tinyusdz::tydra::AnimationChannel::ChannelType::Rotation:
+                    if (animChannel.rotations.static_value.has_value()) {
+                        rotationKeys.emplace_back(0, tinyUsdzQuatToAiQuat(animChannel.rotations.static_value.value()));
+                    }
+                    for (const auto &rotationAnimSampler : animChannel.rotations.samples) {
+                        if (rotationAnimSampler.t > newAiAnimation->mDuration) {
+                            newAiAnimation->mDuration = rotationAnimSampler.t;
+                        }
+
+                        rotationKeys.emplace_back(rotationAnimSampler.t, tinyUsdzQuatToAiQuat(rotationAnimSampler.value));
+                    }
+                    break;
+                case tinyusdz::tydra::AnimationChannel::ChannelType::Scale:
+                    if (animChannel.scales.static_value.has_value()) {
+                        scalingKeys.emplace_back(0, tinyUsdzScaleOrPosToAssimp(animChannel.scales.static_value.value()));
+                    }
+                    for (const auto &scaleAnimSampler : animChannel.scales.samples) {
+                        if (scaleAnimSampler.t > newAiAnimation->mDuration) {
+                            newAiAnimation->mDuration = scaleAnimSampler.t;
+                        }
+                        scalingKeys.emplace_back(scaleAnimSampler.t, tinyUsdzScaleOrPosToAssimp(scaleAnimSampler.value));
+                    }
+                    break;
+                case tinyusdz::tydra::AnimationChannel::ChannelType::Transform:
+                    if (animChannel.transforms.static_value.has_value()) {
+                        aiVector3D position;
+                        aiVector3D scale;
+                        aiQuaternion rotation;
+                        tinyUsdzMat4ToAiMat4(animChannel.transforms.static_value.value().m).Decompose(scale, rotation, position);
+
+                        positionKeys.emplace_back(0, position);
+                        scalingKeys.emplace_back(0, scale);
+                        rotationKeys.emplace_back(0, rotation);
+                    }
+                    for (const auto &transformAnimSampler : animChannel.transforms.samples) {
+                        if (transformAnimSampler.t > newAiAnimation->mDuration) {
+                            newAiAnimation->mDuration = transformAnimSampler.t;
+                        }
+
+                        aiVector3D position;
+                        aiVector3D scale;
+                        aiQuaternion rotation;
+                        tinyUsdzMat4ToAiMat4(transformAnimSampler.value.m).Decompose(scale, rotation, position);
+
+                        positionKeys.emplace_back(transformAnimSampler.t, position);
+                        scalingKeys.emplace_back(transformAnimSampler.t, scale);
+                        rotationKeys.emplace_back(transformAnimSampler.t, rotation);
+                    }
+                    break;
+                case tinyusdz::tydra::AnimationChannel::ChannelType::Translation:
+                    if (animChannel.translations.static_value.has_value()) {
+                        positionKeys.emplace_back(0, tinyUsdzScaleOrPosToAssimp(animChannel.translations.static_value.value()));
+                    }
+                    for (const auto &translationAnimSampler : animChannel.translations.samples) {
+                        if (translationAnimSampler.t > newAiAnimation->mDuration) {
+                            newAiAnimation->mDuration = translationAnimSampler.t;
+                        }
+
+                        positionKeys.emplace_back(translationAnimSampler.t, tinyUsdzScaleOrPosToAssimp(translationAnimSampler.value));
+                    }
+                    break;
+                default:
+                    TINYUSDZLOGW(TAG, "Unsupported animation channel type (%s). Please update the USD importer to support this animation channel.", tinyusdzAnimChannelTypeFor(channelType).c_str());
+                }
+            }
+
+            newAiNodeAnim->mNumPositionKeys = positionKeys.size();
+            newAiNodeAnim->mPositionKeys = new aiVectorKey[newAiNodeAnim->mNumPositionKeys];
+            std::move(positionKeys.begin(), positionKeys.end(), newAiNodeAnim->mPositionKeys);
+
+            newAiNodeAnim->mNumRotationKeys = rotationKeys.size();
+            newAiNodeAnim->mRotationKeys = new aiQuatKey[newAiNodeAnim->mNumRotationKeys];
+            std::move(rotationKeys.begin(), rotationKeys.end(), newAiNodeAnim->mRotationKeys);
+
+            newAiNodeAnim->mNumScalingKeys = scalingKeys.size();
+            newAiNodeAnim->mScalingKeys = new aiVectorKey[newAiNodeAnim->mNumScalingKeys];
+            std::move(scalingKeys.begin(), scalingKeys.end(), newAiNodeAnim->mScalingKeys);
+
+            ++channelIndex;
+        }
+    }
+}
 
 void USDImporterImplTinyusdz::meshes(
         const tinyusdz::tydra::RenderScene &render_scene,
@@ -247,8 +391,66 @@ void USDImporterImplTinyusdz::verticesForMesh(
         size_t meshIdx,
         const std::string &nameWExt) {
     UNUSED(nameWExt);
-    pScene->mMeshes[meshIdx]->mNumVertices = static_cast<unsigned int>(render_scene.meshes[meshIdx].points.size());
+    const auto numVertices = static_cast<unsigned int>(render_scene.meshes[meshIdx].points.size());
+    pScene->mMeshes[meshIdx]->mNumVertices = numVertices;
     pScene->mMeshes[meshIdx]->mVertices = new aiVector3D[pScene->mMeshes[meshIdx]->mNumVertices];
+
+    // Check if this is a skinned mesh
+    if (int skeleton_id = render_scene.meshes[meshIdx].skel_id; skeleton_id > -1) {
+        // Recursively iterate to collect all the joints in the hierarchy into a flattened array
+        std::vector<const tinyusdz::tydra::SkelNode *> skeletonNodes;
+        skeletonNodes.push_back(&render_scene.skeletons[skeleton_id].root_node);
+        for (int i = 0; i < skeletonNodes.size(); ++i) {
+            for (const auto &child : skeletonNodes[i]->children) {
+                skeletonNodes.push_back(&child);
+            }
+        }
+
+        // Convert USD skeleton joints to Assimp bones
+        const unsigned int numBones = skeletonNodes.size();
+        pScene->mMeshes[meshIdx]->mNumBones = numBones;
+        pScene->mMeshes[meshIdx]->mBones = new aiBone *[numBones];
+
+        for (unsigned int i = 0; i < numBones; ++i) {
+            const tinyusdz::tydra::SkelNode *skeletonNode = skeletonNodes[i];
+            const int boneIndex = skeletonNode->joint_id;
+
+            // Sorted so that Assimp bone ids align with USD joint id
+            auto outputBone = new aiBone();
+            outputBone->mName = aiString(skeletonNode->joint_name);
+            outputBone->mOffsetMatrix = tinyUsdzMat4ToAiMat4(skeletonNode->bind_transform.m).Inverse();
+            pScene->mMeshes[meshIdx]->mBones[boneIndex] = outputBone;
+        }
+
+        // Vertex weights
+        std::vector<std::vector<aiVertexWeight>> aiBonesVertexWeights;
+        aiBonesVertexWeights.resize(numBones);
+
+        const std::vector<int> &jointIndices = render_scene.meshes[meshIdx].joint_and_weights.jointIndices;
+        const std::vector<float> &jointWeightIndices = render_scene.meshes[meshIdx].joint_and_weights.jointWeights;
+        const int numWeightsPerVertex = render_scene.meshes[meshIdx].joint_and_weights.elementSize;
+
+        for (unsigned int vertexIndex = 0; vertexIndex < numVertices; ++vertexIndex) {
+            for (int weightIndex = 0; weightIndex < numWeightsPerVertex; ++weightIndex) {
+                const unsigned int index = vertexIndex * numWeightsPerVertex + weightIndex;
+                const float jointWeight = jointWeightIndices[index];
+
+                if (jointWeight > 0) {
+                    const int jointIndex = jointIndices[index];
+                    aiBonesVertexWeights[jointIndex].emplace_back(vertexIndex, jointWeight);
+                }
+            }
+        }
+
+        for (int boneIndex = 0; boneIndex < numBones; ++boneIndex) {
+            const unsigned int numWeightsForBone = aiBonesVertexWeights[boneIndex].size();
+            pScene->mMeshes[meshIdx]->mBones[boneIndex]->mWeights = new aiVertexWeight[numWeightsForBone];
+            pScene->mMeshes[meshIdx]->mBones[boneIndex]->mNumWeights = numWeightsForBone;
+
+            std::swap_ranges(aiBonesVertexWeights[boneIndex].begin(), aiBonesVertexWeights[boneIndex].end(), pScene->mMeshes[meshIdx]->mBones[boneIndex]->mWeights);
+        }
+    }  // Skinned mesh end
+
     for (size_t j = 0; j < pScene->mMeshes[meshIdx]->mNumVertices; ++j) {
         pScene->mMeshes[meshIdx]->mVertices[j].x = render_scene.meshes[meshIdx].points[j][0];
         pScene->mMeshes[meshIdx]->mVertices[j].y = render_scene.meshes[meshIdx].points[j][1];
@@ -595,54 +797,25 @@ void USDImporterImplTinyusdz::buffers(
     }
 }
 
-void USDImporterImplTinyusdz::setupNodes(
-        const tinyusdz::tydra::RenderScene &render_scene,
-        aiScene *pScene,
-        std::map<size_t, tinyusdz::tydra::Node> &meshNodes,
-        const std::string &nameWExt) {
-    stringstream ss;
-
-    pScene->mRootNode = nodes(render_scene, meshNodes, nameWExt);
-    pScene->mRootNode->mNumMeshes = pScene->mNumMeshes;
-    pScene->mRootNode->mMeshes = new unsigned int[pScene->mRootNode->mNumMeshes];
-    ss.str("");
-    ss << "setupNodes(): pScene->mNumMeshes: " << pScene->mNumMeshes;
-    if (pScene->mRootNode != nullptr) {
-        ss << ", mRootNode->mNumMeshes: " << pScene->mRootNode->mNumMeshes;
-    }
-    TINYUSDZLOGD(TAG, "%s", ss.str().c_str());
-
-    for (unsigned int meshIdx = 0; meshIdx < pScene->mNumMeshes; meshIdx++) {
-        pScene->mRootNode->mMeshes[meshIdx] = meshIdx;
-    }
-
-}
-
-aiNode *USDImporterImplTinyusdz::nodes(
-        const tinyusdz::tydra::RenderScene &render_scene,
-        std::map<size_t, tinyusdz::tydra::Node> &meshNodes,
-        const std::string &nameWExt) {
-    const size_t numNodes{render_scene.nodes.size()};
-    (void) numNodes; // Ignore unused variable when -Werror enabled
-    stringstream ss;
-    ss.str("");
-    ss << "nodes(): model" << nameWExt << ", numNodes: " << numNodes;
-    TINYUSDZLOGD(TAG, "%s", ss.str().c_str());
-    return nodesRecursive(nullptr, render_scene.nodes[0], meshNodes);
-}
-
 using Assimp::tinyusdzNodeTypeFor;
 using Assimp::tinyUsdzMat4ToAiMat4;
 using tinyusdz::tydra::NodeType;
 aiNode *USDImporterImplTinyusdz::nodesRecursive(
         aiNode *pNodeParent,
         const tinyusdz::tydra::Node &node,
-        std::map<size_t, tinyusdz::tydra::Node> &meshNodes) {
+        const std::vector<tinyusdz::tydra::SkelHierarchy> &skeletons) {
     stringstream ss;
     aiNode *cNode = new aiNode();
     cNode->mParent = pNodeParent;
     cNode->mName.Set(node.prim_name);
     cNode->mTransformation = tinyUsdzMat4ToAiMat4(node.local_matrix.m);
+
+    if (node.nodeType == NodeType::Mesh) {
+        cNode->mNumMeshes = 1;
+        cNode->mMeshes = new unsigned int[cNode->mNumMeshes];
+        cNode->mMeshes[0] = node.id;
+    }
+
     ss.str("");
     ss << "nodesRecursive(): node " << cNode->mName.C_Str() <<
             " type: |" << tinyusdzNodeTypeFor(node.nodeType) <<
@@ -651,21 +824,69 @@ aiNode *USDImporterImplTinyusdz::nodesRecursive(
         ss << " (parent " << cNode->mParent->mName.C_Str() << ")";
     }
     ss << " has " << node.children.size() << " children";
-    if (node.id > -1) {
+    if (node.nodeType == NodeType::Mesh) {
         ss << "\n    node mesh id: " << node.id << " (node type: " << tinyusdzNodeTypeFor(node.nodeType) << ")";
-        meshNodes[node.id] = node;
     }
     TINYUSDZLOGD(TAG, "%s", ss.str().c_str());
-    if (!node.children.empty()) {
-        cNode->mNumChildren = static_cast<unsigned int>(node.children.size());
-        cNode->mChildren = new aiNode *[cNode->mNumChildren];
+
+    unsigned int numChildren = node.children.size();
+
+    // Find any tinyusdz skeletons which might begin at this node
+    // Add the skeleton bones as child nodes
+    const tinyusdz::tydra::SkelNode *skelNode = nullptr;
+    for (const auto &skeleton : skeletons) {
+        if (skeleton.abs_path == node.abs_path) {
+            // Add this skeleton's bones as child nodes
+            ++numChildren;
+            skelNode = &skeleton.root_node;
+            break;
+        }
     }
 
-    size_t i{0};
-    for (const auto &childNode: node.children) {
-        cNode->mChildren[i] = nodesRecursive(cNode, childNode, meshNodes);
+    cNode->mNumChildren = numChildren;
+
+    // Done. No more children.
+    if (numChildren == 0) {
+        return cNode;
+    }
+
+    cNode->mChildren = new aiNode *[cNode->mNumChildren];
+
+    size_t i{ 0 };
+    for (const auto &childNode : node.children) {
+        cNode->mChildren[i] = nodesRecursive(cNode, childNode, skeletons);
         ++i;
     }
+
+    if (skelNode != nullptr) {
+        // Convert USD skeleton into an Assimp node and make it the last child
+        cNode->mChildren[cNode->mNumChildren-1] = skeletonNodesRecursive(cNode, *skelNode);
+    }
+
+    return cNode;
+}
+
+aiNode *USDImporterImplTinyusdz::skeletonNodesRecursive(
+        aiNode* pNodeParent,
+        const tinyusdz::tydra::SkelNode& joint) {
+    auto *cNode = new aiNode(joint.joint_path);
+    cNode->mParent = pNodeParent;
+    cNode->mNumMeshes = 0; // not a mesh node
+    cNode->mTransformation = tinyUsdzMat4ToAiMat4(joint.rest_transform.m);
+
+    // Done. No more children.
+    if (joint.children.empty()) {
+        return cNode;
+    }
+
+    cNode->mNumChildren = static_cast<unsigned int>(joint.children.size());
+    cNode->mChildren = new aiNode *[cNode->mNumChildren];
+
+    for (int i = 0; i < cNode->mNumChildren; ++i) {
+        const tinyusdz::tydra::SkelNode &childJoint = joint.children[i];
+        cNode->mChildren[i] = skeletonNodesRecursive(cNode, childJoint);
+    }
+
     return cNode;
 }
 
diff --git a/code/AssetLib/USD/USDLoaderImplTinyusdz.h b/code/AssetLib/USD/USDLoaderImplTinyusdz.h
index 69f8c125c..8d52cc383 100644
--- a/code/AssetLib/USD/USDLoaderImplTinyusdz.h
+++ b/code/AssetLib/USD/USDLoaderImplTinyusdz.h
@@ -65,6 +65,10 @@ public:
             aiScene *pScene,
             IOSystem *pIOHandler);
 
+    void animations(
+            const tinyusdz::tydra::RenderScene &render_scene,
+            aiScene *pScene);
+
     void meshes(
             const tinyusdz::tydra::RenderScene &render_scene,
             aiScene *pScene,
@@ -120,22 +124,14 @@ public:
             aiScene *pScene,
             const std::string &nameWExt);
 
-    void setupNodes(
-            const tinyusdz::tydra::RenderScene &render_scene,
-            aiScene *pScene,
-            std::map<size_t, tinyusdz::tydra::Node> &meshNodes,
-            const std::string &nameWExt
-            );
-
-    aiNode *nodes(
-            const tinyusdz::tydra::RenderScene &render_scene,
-            std::map<size_t, tinyusdz::tydra::Node> &meshNodes,
-            const std::string &nameWExt);
-
     aiNode *nodesRecursive(
             aiNode *pNodeParent,
             const tinyusdz::tydra::Node &node,
-            std::map<size_t, tinyusdz::tydra::Node> &meshNodes);
+            const std::vector<tinyusdz::tydra::SkelHierarchy> &skeletons);
+
+    aiNode *skeletonNodesRecursive(
+            aiNode *pNodeParent,
+            const tinyusdz::tydra::SkelNode &joint);
 
     void sanityCheckNodesRecursive(
             aiNode *pNode);
diff --git a/code/AssetLib/USD/USDLoaderImplTinyusdzHelper.cpp b/code/AssetLib/USD/USDLoaderImplTinyusdzHelper.cpp
index 09d692445..6708d7972 100644
--- a/code/AssetLib/USD/USDLoaderImplTinyusdzHelper.cpp
+++ b/code/AssetLib/USD/USDLoaderImplTinyusdzHelper.cpp
@@ -100,43 +100,6 @@ std::string Assimp::tinyusdzNodeTypeFor(NodeType type) {
     }
 }
 
-aiMatrix4x4 Assimp::tinyUsdzMat4ToAiMat4(const double matIn[4][4]) {
-    aiMatrix4x4 matOut;
-    matOut.a1 = matIn[0][0];
-    matOut.a2 = matIn[0][1];
-    matOut.a3 = matIn[0][2];
-    matOut.a4 = matIn[0][3];
-    matOut.b1 = matIn[1][0];
-    matOut.b2 = matIn[1][1];
-    matOut.b3 = matIn[1][2];
-    matOut.b4 = matIn[1][3];
-    matOut.c1 = matIn[2][0];
-    matOut.c2 = matIn[2][1];
-    matOut.c3 = matIn[2][2];
-    matOut.c4 = matIn[2][3];
-    matOut.d1 = matIn[3][0];
-    matOut.d2 = matIn[3][1];
-    matOut.d3 = matIn[3][2];
-    matOut.d4 = matIn[3][3];
-//    matOut.a1 = matIn[0][0];
-//    matOut.a2 = matIn[1][0];
-//    matOut.a3 = matIn[2][0];
-//    matOut.a4 = matIn[3][0];
-//    matOut.b1 = matIn[0][1];
-//    matOut.b2 = matIn[1][1];
-//    matOut.b3 = matIn[2][1];
-//    matOut.b4 = matIn[3][1];
-//    matOut.c1 = matIn[0][2];
-//    matOut.c2 = matIn[1][2];
-//    matOut.c3 = matIn[2][2];
-//    matOut.c4 = matIn[3][2];
-//    matOut.d1 = matIn[0][3];
-//    matOut.d2 = matIn[1][3];
-//    matOut.d3 = matIn[2][3];
-//    matOut.d4 = matIn[3][3];
-    return matOut;
-}
-
 aiVector3D Assimp::tinyUsdzScaleOrPosToAssimp(const std::array<float, 3> &scaleOrPosIn) {
     return aiVector3D(scaleOrPosIn[0], scaleOrPosIn[1], scaleOrPosIn[2]);
 }
diff --git a/code/AssetLib/USD/USDLoaderImplTinyusdzHelper.h b/code/AssetLib/USD/USDLoaderImplTinyusdzHelper.h
index c5eaafd73..42a7b9d9f 100644
--- a/code/AssetLib/USD/USDLoaderImplTinyusdzHelper.h
+++ b/code/AssetLib/USD/USDLoaderImplTinyusdzHelper.h
@@ -48,14 +48,36 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <assimp/types.h>
 #include "tinyusdz.hh"
 #include "tydra/render-data.hh"
+#include <type_traits>
 
 namespace Assimp {
 
 std::string tinyusdzAnimChannelTypeFor(
         tinyusdz::tydra::AnimationChannel::ChannelType animChannel);
 std::string tinyusdzNodeTypeFor(tinyusdz::tydra::NodeType type);
-aiMatrix4x4 tinyUsdzMat4ToAiMat4(const double matIn[4][4]);
 
+template <typename T>
+aiMatrix4x4 tinyUsdzMat4ToAiMat4(const T matIn[4][4]) {
+    static_assert(std::is_floating_point_v<T>, "Only floating-point types are allowed.");
+    aiMatrix4x4 matOut;
+    matOut.a1 = matIn[0][0];
+    matOut.a2 = matIn[1][0];
+    matOut.a3 = matIn[2][0];
+    matOut.a4 = matIn[3][0];
+    matOut.b1 = matIn[0][1];
+    matOut.b2 = matIn[1][1];
+    matOut.b3 = matIn[2][1];
+    matOut.b4 = matIn[3][1];
+    matOut.c1 = matIn[0][2];
+    matOut.c2 = matIn[1][2];
+    matOut.c3 = matIn[2][2];
+    matOut.c4 = matIn[3][2];
+    matOut.d1 = matIn[0][3];
+    matOut.d2 = matIn[1][3];
+    matOut.d3 = matIn[2][3];
+    matOut.d4 = matIn[3][3];
+    return matOut;
+}
 aiVector3D tinyUsdzScaleOrPosToAssimp(const std::array<float, 3> &scaleOrPosIn);
 
 /**
diff --git a/code/CMakeLists.txt b/code/CMakeLists.txt
index 9b2708623..fc6f682ed 100644
--- a/code/CMakeLists.txt
+++ b/code/CMakeLists.txt
@@ -946,8 +946,8 @@ IF (ASSIMP_BUILD_USD_IMPORTER)
     # Note: ALWAYS specify a git commit hash (or tag) instead of a branch name; using a branch
     #       name can lead to non-deterministic (unpredictable) results since the code is potentially
     #       in flux
-    # "dev" branch, 9 Jul 2024
-    set(TINYUSDZ_GIT_TAG "bd2a1edbbf69f352a6c40730114db9918c384848")
+    # "dev" branch, 28 Oct 2024
+    set(TINYUSDZ_GIT_TAG "36f2aabb256b360365989c01a52f839a57dfe2a6")
     message("****")
     message("\n\n**** Cloning tinyusdz repo, git tag ${TINYUSDZ_GIT_TAG}\n\n")
 
diff --git a/code/PostProcessing/ValidateDataStructure.cpp b/code/PostProcessing/ValidateDataStructure.cpp
index 8441b48be..fba81a399 100644
--- a/code/PostProcessing/ValidateDataStructure.cpp
+++ b/code/PostProcessing/ValidateDataStructure.cpp
@@ -447,7 +447,7 @@ void ValidateDSProcess::Validate(const aiMesh *pMesh, const aiBone *pBone, float
         if (pBone->mWeights[i].mVertexId >= pMesh->mNumVertices) {
             ReportError("aiBone::mWeights[%i].mVertexId is out of range", i);
         } else if (!pBone->mWeights[i].mWeight || pBone->mWeights[i].mWeight > 1.0f) {
-            ReportWarning("aiBone::mWeights[%i].mWeight has an invalid value", i);
+                ReportWarning("aiBone::mWeights[%i].mWeight has an invalid value %i. Value must be greater than zero and less than 1.", i, pBone->mWeights[i].mWeight);
         }
         afSum[pBone->mWeights[i].mVertexId] += pBone->mWeights[i].mWeight;
     }
diff --git a/contrib/tinyusdz/patches/tinyusdz.patch b/contrib/tinyusdz/patches/tinyusdz.patch
index e84e9f8fe..7cd703475 100644
--- a/contrib/tinyusdz/patches/tinyusdz.patch
+++ b/contrib/tinyusdz/patches/tinyusdz.patch
@@ -1,7 +1,33 @@
+diff -rupN -x .git autoclone/tinyusdz_repo-src/src/io-util.cc tinyusdz_repo_patch/src/io-util.cc
+--- autoclone/tinyusdz_repo-src/src/io-util.cc	2024-10-27 03:26:45.457163600 -0700
++++ tinyusdz_repo_patch/src/io-util.cc	2024-10-27 03:31:09.255211100 -0700
+@@ -19,6 +19,7 @@
+ 
+ #include <io.h>
+ #include <windows.h>  // include API for expanding a file path
++#include <tchar.h>
+ 
+ #ifndef TINYUSDZ_MMAP_SUPPORTED
+ #define TINYUSDZ_MMAP_SUPPORTED (1)
+@@ -153,9 +154,10 @@ bool MMapFile(const std::string &filepath, MMapFileHandle *handle,
+ 
+ #if TINYUSDZ_MMAP_SUPPORTED
+ #if defined(_WIN32)
+-  // int fd = open(filepath.c_str(), writable ? O_RDWR : O_RDONLY);
++  std::basic_string<TCHAR> tFilepath(filepath.begin(), filepath.end());  // Using TCHAR string to automatically use normal or wide characters if UNICODE is enabled
++
+   HANDLE hFile =
+-      CreateFile(filepath.c_str(), GENERIC_READ, FILE_SHARE_READ, nullptr,
++      CreateFile(tFilepath.c_str(), GENERIC_READ, FILE_SHARE_READ, nullptr,
+                  OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
+   if (hFile == INVALID_HANDLE_VALUE) {
+     if (err) {
+
+
 diff -rupN -x .git autoclone/tinyusdz_repo-src/src/external/stb_image_resize2.h tinyusdz_repo_patch/src/external/stb_image_resize2.h
---- autoclone/tinyusdz_repo-src/src/external/stb_image_resize2.h	2024-07-09 21:29:48.556969900 -0700
-+++ tinyusdz_repo_patch/src/external/stb_image_resize2.h	2024-07-09 23:03:47.379316700 -0700
-@@ -2404,6 +2404,38 @@ static stbir__inline stbir_uint8 stbir__
+--- autoclone/tinyusdz_repo-src/src/external/stb_image_resize2.h	2024-10-27 03:26:45.457163600 -0700
++++ tinyusdz_repo_patch/src/external/stb_image_resize2.h	2024-10-27 03:31:09.255211100 -0700
+@@ -2500,6 +2500,38 @@ static stbir__inline stbir_uint8 stbir__
      }
    }
  
@@ -37,6 +63,6 @@ diff -rupN -x .git autoclone/tinyusdz_repo-src/src/external/stb_image_resize2.h
 +    return 0;
 +  }
 +
- #elif defined(STBIR_NEON) && defined(_MSC_VER) && defined(_M_ARM64) && !defined(__clang__) // 64-bit ARM on MSVC (not clang)
+ #endif
+ 
  
-   static stbir__inline void stbir__half_to_float_SIMD(float * output, stbir__FP16 const * input)
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 7b7fd850a..fe80edcb3 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -148,7 +148,6 @@ SET( IMPORTERS
   #unit/utM3DImportExport.cpp
   unit/utMDCImportExport.cpp
   unit/utAssbinImportExport.cpp
-  unit/utUSDImport.cpp
   unit/ImportExport/utAssjsonImportExport.cpp
   unit/ImportExport/utCOBImportExport.cpp
   unit/ImportExport/utOgreImportExport.cpp
@@ -169,6 +168,12 @@ SET( IMPORTERS
   unit/ImportExport/Pbrt/utPbrtImportExport.cpp
 )
 
+if(ASSIMP_BUILD_USD_IMPORTER)
+  list( APPEND IMPORTERS
+    unit/utUSDImport.cpp
+  )
+endif()
+
 SET( MATERIAL
   unit/utMaterialSystem.cpp
 )
diff --git a/test/models-nonbsd/USD/usda/README.md b/test/models-nonbsd/USD/usda/README.md
index e860175fd..cb5477b26 100644
--- a/test/models-nonbsd/USD/usda/README.md
+++ b/test/models-nonbsd/USD/usda/README.md
@@ -1,3 +1,5 @@
 [blendshape.usda](blendshape.usda) copied from tinyusdz/models (No attribution/license cited in that project)
 [texturedcube.usda](texturedcube.usda) copied from tinyusdz/models (No attribution/license cited in that project)
 [translated-cube.usda](translated-cube.usda) copied from tinyusdz/models (No attribution/license cited in that project)
+[simple-skin-test.usda](simple-skin-test.usda) copied from tinyusdz/models (No attribution/license cited in that project)
+[simple-skin-animation-test.usda](simple-skin-animation-test.usda) modified tinyusdz/models (No attribution/license cited in that project)
diff --git a/test/models-nonbsd/USD/usda/simple-skin-animation-test.usda b/test/models-nonbsd/USD/usda/simple-skin-animation-test.usda
new file mode 100644
index 000000000..2324c2064
--- /dev/null
+++ b/test/models-nonbsd/USD/usda/simple-skin-animation-test.usda
@@ -0,0 +1,237 @@
+#usda 1.0
+(
+    defaultPrim = "root"
+    doc = "Blender v4.2.3 LTS"
+    endTimeCode = 40
+    metersPerUnit = 1
+    startTimeCode = 0
+    timeCodesPerSecond = 24
+    upAxis = "Z"
+)
+
+def Xform "root" (
+    customData = {
+        dictionary Blender = {
+            bool generated = 1
+        }
+    }
+)
+{
+    def SkelRoot "Armature_001"
+    {
+        custom string userProperties:blender:object_name = "Armature.001"
+        float3 xformOp:rotateXYZ = (-89.99999, 0, 0)
+        float3 xformOp:scale = (1, 1, 1)
+        double3 xformOp:translate = (0, -1.7017418146133423, 0)
+        uniform token[] xformOpOrder = ["xformOp:translate", "xformOp:rotateXYZ", "xformOp:scale"]
+
+        def Xform "Grid"
+        {
+            custom string userProperties:blender:object_name = "Grid"
+            float3 xformOp:rotateXYZ = (89.99999, -0, 0)
+            float3 xformOp:scale = (1, 1, 1)
+            double3 xformOp:translate = (0, -7.438549687321938e-8, 1.7017418146133423)
+            uniform token[] xformOpOrder = ["xformOp:translate", "xformOp:rotateXYZ", "xformOp:scale"]
+
+            def Mesh "Grid" (
+                active = true
+                prepend apiSchemas = ["SkelBindingAPI"]
+            )
+            {
+                float3[] extent = [(-1, -1, 0), (1, 1, 0)]
+                int[] faceVertexCounts = [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4]
+                int[] faceVertexIndices = [0, 1, 6, 5, 1, 2, 7, 6, 2, 3, 8, 7, 3, 4, 9, 8, 5, 6, 11, 10, 6, 7, 12, 11, 7, 8, 13, 12, 8, 9, 14, 13, 10, 11, 16, 15, 11, 12, 17, 16, 12, 13, 18, 17, 13, 14, 19, 18, 15, 16, 21, 20, 16, 17, 22, 21, 17, 18, 23, 22, 18, 19, 24, 23]
+                normal3f[] normals = [(0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1)] (
+                    interpolation = "faceVarying"
+                )
+                point3f[] points = [(-1, -1, 0), (-0.5, -1, 0), (0, -1, 0), (0.5, -1, 0), (1, -1, 0), (-1, -0.5, 0), (-0.5, -0.5, 0), (0, -0.5, 0), (0.5, -0.5, 0), (1, -0.5, 0), (-1, 0, 0), (-0.5, 0, 0), (0, 0, 0), (0.5, 0, 0), (1, 0, 0), (-1, 0.5, 0), (-0.5, 0.5, 0), (0, 0.5, 0), (0.5, 0.5, 0), (1, 0.5, 0), (-1, 1, 0), (-0.5, 1, 0), (0, 1, 0), (0.5, 1, 0), (1, 1, 0)]
+                bool[] primvars:sharp_face = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] (
+                    interpolation = "uniform"
+                )
+                matrix4d primvars:skel:geomBindTransform = ( (1, 0, 0, 0), (0, 1.331580543606492e-7, 0.9999999999999911, 0), (0, -0.9999999999999911, 1.331580543606492e-7, 0), (0, -7.438549687321943e-8, 1.701741814613342, 1) )
+                int[] primvars:skel:jointIndices = [0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1] (
+                    elementSize = 2
+                    interpolation = "vertex"
+                )
+                float[] primvars:skel:jointWeights = [0.43767902, 0.56232095, 0.605441, 0.39455906, 1, 0, 0.605441, 0.39455906, 0.43767902, 0.562321, 0.23470172, 0.7652983, 0.18096954, 0.81903046, 1, 0, 0.18096954, 0.81903046, 0.23470171, 0.7652983, 0.114853, 0.88514704, 0.06506716, 0.9349329, 1, 0, 0.06506715, 0.9349329, 0.11485299, 0.88514704, 0.059175473, 0.94082457, 0.009479873, 0.9905201, 1, 0, 0.009479865, 0.9905201, 0.059175465, 0.94082457, 0.031181445, 0.96881855, 1, 0, 1, 0, 1, 0, 0.031181442, 0.9688186] (
+                    elementSize = 2
+                    interpolation = "vertex"
+                )
+                texCoord2f[] primvars:st = [(0, 0), (0.25, 0), (0.25, 0.25), (0, 0.25), (0.25, 0), (0.5, 0), (0.5, 0.25), (0.25, 0.25), (0.5, 0), (0.75, 0), (0.75, 0.25), (0.5, 0.25), (0.75, 0), (1, 0), (1, 0.25), (0.75, 0.25), (0, 0.25), (0.25, 0.25), (0.25, 0.5), (0, 0.5), (0.25, 0.25), (0.5, 0.25), (0.5, 0.5), (0.25, 0.5), (0.5, 0.25), (0.75, 0.25), (0.75, 0.5), (0.5, 0.5), (0.75, 0.25), (1, 0.25), (1, 0.5), (0.75, 0.5), (0, 0.5), (0.25, 0.5), (0.25, 0.75), (0, 0.75), (0.25, 0.5), (0.5, 0.5), (0.5, 0.75), (0.25, 0.75), (0.5, 0.5), (0.75, 0.5), (0.75, 0.75), (0.5, 0.75), (0.75, 0.5), (1, 0.5), (1, 0.75), (0.75, 0.75), (0, 0.75), (0.25, 0.75), (0.25, 1), (0, 1), (0.25, 0.75), (0.5, 0.75), (0.5, 1), (0.25, 1), (0.5, 0.75), (0.75, 0.75), (0.75, 1), (0.5, 1), (0.75, 0.75), (1, 0.75), (1, 1), (0.75, 1)] (
+                    interpolation = "faceVarying"
+                )
+                rel skel:skeleton = </root/Armature_001/Armature/Armature>
+                uniform token subdivisionScheme = "none"
+                custom string userProperties:blender:data_name = "Grid"
+            }
+        }
+
+        def Xform "Armature"
+        {
+            custom string userProperties:blender:object_name = "Armature"
+            float3 xformOp:rotateXYZ.timeSamples = {
+                0: (0, -0, 0),
+            }
+            float3 xformOp:scale.timeSamples = {
+                0: (1, 1, 1),
+            }
+            double3 xformOp:translate.timeSamples = {
+                0: (0, 0, 0),
+            }
+            uniform token[] xformOpOrder = ["xformOp:translate", "xformOp:rotateXYZ", "xformOp:scale"]
+
+            def Skeleton "Armature" (
+                prepend apiSchemas = ["SkelBindingAPI"]
+            )
+            {
+                uniform matrix4d[] bindTransforms = [( (1, 0, 0, 0), (0, 0, 1, 0), (0, -1, 0, 0), (0, 0, 0, 1) ), ( (1, 0, 0, 0), (0, 0, 1, 0), (0, -1, 0, 0), (0, 0, 1, 1) )]
+                uniform token[] joints = ["Bone", "Bone/Bone_001"]
+                uniform matrix4d[] restTransforms = [( (1, 0, 0, 0), (0, 0, 1, 0), (0, -1, 0, 0), (0, 0, 0, 1) ), ( (1, 0, 0, 0), (0, 1, 0, 0), (0, 0, 1, 0), (0, 1, 0, 1) )]
+                rel skel:animationSource = </root/Armature_001/Armature/Armature/Anim>
+
+                def SkelAnimation "Anim"
+                {
+                    uniform token[] joints = ["Bone", "Bone/Bone_001"]
+                    quatf[] rotations.timeSamples = {
+                        0: [(0.70710677, 0.70710677, 0, 0), (1, 0, 0, 0)],
+                        1: [(0.70710677, 0.70710677, 0, 0), (0.9996082, 0, 0, 0.027989032)],
+                        2: [(0.70710677, 0.70710677, 0, 0), (0.99463546, 0, 0, 0.10344209)],
+                        3: [(0.70710677, 0.70710677, 0, 0), (0.9774578, 0, 0, 0.21113087)],
+                        4: [(0.70710677, 0.70710677, 0, 0), (0.9432686, 0, 0, 0.3320306)],
+                        5: [(0.70710677, 0.70710677, 0, 0), (0.89442724, 0, 0, 0.4472135)],
+                        6: [(0.70710677, 0.70710677, 0, 0), (0.83920974, 0, 0, 0.5438079)],
+                        7: [(0.70710677, 0.70710677, 0, 0), (0.7869733, 0, 0, 0.61698705)],
+                        8: [(0.70710677, 0.70710677, 0, 0), (0.7447736, 0, 0, 0.6673172)],
+                        9: [(0.70710677, 0.70710677, 0, 0), (0.7170745, 0, 0, 0.6969965)],
+                        10: [(0.70710677, 0.70710677, 0, 0), (0.70710677, 0, 0, 0.70710677)],
+                        11: [(0.70710677, 0.70710677, 0, 0), (0.7122517, 0, 0, 0.70192415)],
+                        12: [(0.70710677, 0.70710677, 0, 0), (0.7271744, 0, 0, 0.68645275)],
+                        13: [(0.70710677, 0.70710677, 0, 0), (0.75127214, 0, 0, 0.6599926)],
+                        14: [(0.70710677, 0.70710677, 0, 0), (0.7839187, 0, 0, 0.62086356)],
+                        15: [(0.70710677, 0.70710677, 0, 0), (0.82404196, 0, 0, 0.5665288)],
+                        16: [(0.70710677, 0.70710677, 0, 0), (0.8695245, 0, 0, 0.49388987)],
+                        17: [(0.70710677, 0.70710677, 0, 0), (0.91649354, 0, 0, 0.4000495)],
+                        18: [(0.70710677, 0.70710677, 0, 0), (0.9588755, 0, 0, 0.28382713)],
+                        19: [(0.70710677, 0.70710677, 0, 0), (0.9890088, 0, 0, 0.14785683)],
+                        20: [(0.70710677, 0.70710677, 0, 0), (1, 0, 0, 0)],
+                        21: [(0.70710677, 0.70710677, 0, 0), (0.9890088, 0, 0, -0.14785682)],
+                        22: [(0.70710677, 0.70710677, 0, 0), (0.9588755, 0, 0, -0.28382716)],
+                        23: [(0.70710677, 0.70710677, 0, 0), (0.91649354, 0, 0, -0.40004945)],
+                        24: [(0.70710677, 0.70710677, 0, 0), (0.86952454, 0, 0, -0.49388978)],
+                        25: [(0.70710677, 0.70710677, 0, 0), (0.82404196, 0, 0, -0.5665288)],
+                        26: [(0.70710677, 0.70710677, 0, 0), (0.7839186, 0, 0, -0.6208636)],
+                        27: [(0.70710677, 0.70710677, 0, 0), (0.7512721, 0, 0, -0.65999264)],
+                        28: [(0.70710677, 0.70710677, 0, 0), (0.7271744, 0, 0, -0.68645275)],
+                        29: [(0.70710677, 0.70710677, 0, 0), (0.7122517, 0, 0, -0.70192415)],
+                        30: [(0.70710677, 0.70710677, 0, 0), (0.70710677, 0, 0, -0.70710677)],
+                        31: [(0.70710677, 0.70710677, 0, 0), (0.7170746, 0, 0, -0.69699645)],
+                        32: [(0.70710677, 0.70710677, 0, 0), (0.7447736, 0, 0, -0.6673172)],
+                        33: [(0.70710677, 0.70710677, 0, 0), (0.7869733, 0, 0, -0.61698705)],
+                        34: [(0.70710677, 0.70710677, 0, 0), (0.83920974, 0, 0, -0.5438079)],
+                        35: [(0.70710677, 0.70710677, 0, 0), (0.8944272, 0, 0, -0.44721356)],
+                        36: [(0.70710677, 0.70710677, 0, 0), (0.9432686, 0, 0, -0.3320306)],
+                        37: [(0.70710677, 0.70710677, 0, 0), (0.97745776, 0, 0, -0.21113095)],
+                        38: [(0.70710677, 0.70710677, 0, 0), (0.99463546, 0, 0, -0.10344207)],
+                        39: [(0.70710677, 0.70710677, 0, 0), (0.9996082, 0, 0, -0.027989028)],
+                        40: [(0.70710677, 0.70710677, 0, 0), (1, 0, 0, 0)],
+                    }
+                    half3[] scales.timeSamples = {
+                        0: [(1, 1, 1), (1, 1, 1)],
+                        1: [(1, 1, 1), (1, 1, 1)],
+                        2: [(1, 1, 1), (1, 1, 1)],
+                        3: [(1, 1, 1), (1, 1, 1)],
+                        4: [(1, 1, 1), (1, 1, 1)],
+                        5: [(1, 1, 1), (1, 1, 1)],
+                        6: [(1, 1, 1), (1, 1, 1)],
+                        7: [(1, 1, 1), (1, 1, 1)],
+                        8: [(1, 1, 1), (1, 1, 1)],
+                        9: [(1, 1, 1), (1, 1, 1)],
+                        10: [(1, 1, 1), (1, 1, 1)],
+                        11: [(1, 1, 1), (1, 1, 1)],
+                        12: [(1, 1, 1), (1, 1, 1)],
+                        13: [(1, 1, 1), (1, 1, 1)],
+                        14: [(1, 1, 1), (1, 1, 1)],
+                        15: [(1, 1, 1), (1, 1, 1)],
+                        16: [(1, 1, 1), (1, 1, 1)],
+                        17: [(1, 1, 1), (1, 1, 1)],
+                        18: [(1, 1, 1), (1, 1, 1)],
+                        19: [(1, 1, 1), (1, 1, 1)],
+                        20: [(1, 1, 1), (1, 1, 1)],
+                        21: [(1, 1, 1), (1, 1, 1)],
+                        22: [(1, 1, 1), (1, 1, 1)],
+                        23: [(1, 1, 1), (1, 1, 1)],
+                        24: [(1, 1, 1), (1, 1, 1)],
+                        25: [(1, 1, 1), (1, 1, 1)],
+                        26: [(1, 1, 1), (1, 1, 1)],
+                        27: [(1, 1, 1), (1, 1, 1)],
+                        28: [(1, 1, 1), (1, 1, 1)],
+                        29: [(1, 1, 1), (1, 1, 1)],
+                        30: [(1, 1, 1), (1, 1, 1)],
+                        31: [(1, 1, 1), (1, 1, 1)],
+                        32: [(1, 1, 1), (1, 1, 1)],
+                        33: [(1, 1, 1), (1, 1, 1)],
+                        34: [(1, 1, 1), (1, 1, 1)],
+                        35: [(1, 1, 1), (1, 1, 1)],
+                        36: [(1, 1, 1), (1, 1, 1)],
+                        37: [(1, 1, 1), (1, 1, 1)],
+                        38: [(1, 1, 1), (1, 1, 1)],
+                        39: [(1, 1, 1), (1, 1, 1)],
+                        40: [(1, 1, 1), (1, 1, 1)],
+                    }
+                    float3[] translations.timeSamples = {
+                        0: [(0, 0, 0), (0, 1, 0)],
+                        1: [(0, 0, 0), (0, 1, 0)],
+                        2: [(0, 0, 0), (0, 1, 0)],
+                        3: [(0, 0, 0), (0, 1, 0)],
+                        4: [(0, 0, 0), (0, 1, 0)],
+                        5: [(0, 0, 0), (0, 1, 0)],
+                        6: [(0, 0, 0), (0, 1, 0)],
+                        7: [(0, 0, 0), (0, 1, 0)],
+                        8: [(0, 0, 0), (0, 1, 0)],
+                        9: [(0, 0, 0), (0, 1, 0)],
+                        10: [(0, 0, 0), (0, 1, 0)],
+                        11: [(0, 0, 0), (0, 1, 0)],
+                        12: [(0, 0, 0), (0, 1, 0)],
+                        13: [(0, 0, 0), (0, 1, 0)],
+                        14: [(0, 0, 0), (0, 1, 0)],
+                        15: [(0, 0, 0), (0, 1, 0)],
+                        16: [(0, 0, 0), (0, 1, 0)],
+                        17: [(0, 0, 0), (0, 1, 0)],
+                        18: [(0, 0, 0), (0, 1, 0)],
+                        19: [(0, 0, 0), (0, 1, 0)],
+                        20: [(0, 0, 0), (0, 1, 0)],
+                        21: [(0, 0, 0), (0, 1, 0)],
+                        22: [(0, 0, 0), (0, 1, 0)],
+                        23: [(0, 0, 0), (0, 1, 0)],
+                        24: [(0, 0, 0), (0, 1, 0)],
+                        25: [(0, 0, 0), (0, 1, 0)],
+                        26: [(0, 0, 0), (0, 1, 0)],
+                        27: [(0, 0, 0), (0, 1, 0)],
+                        28: [(0, 0, 0), (0, 1, 0)],
+                        29: [(0, 0, 0), (0, 1, 0)],
+                        30: [(0, 0, 0), (0, 1, 0)],
+                        31: [(0, 0, 0), (0, 1, 0)],
+                        32: [(0, 0, 0), (0, 1, 0)],
+                        33: [(0, 0, 0), (0, 1, 0)],
+                        34: [(0, 0, 0), (0, 1, 0)],
+                        35: [(0, 0, 0), (0, 1, 0)],
+                        36: [(0, 0, 0), (0, 1, 0)],
+                        37: [(0, 0, 0), (0, 1, 0)],
+                        38: [(0, 0, 0), (0, 1, 0)],
+                        39: [(0, 0, 0), (0, 1, 0)],
+                        40: [(0, 0, 0), (0, 1, 0)],
+                    }
+                }
+            }
+        }
+    }
+
+    def DomeLight "env_light"
+    {
+        float inputs:intensity = 1
+        asset inputs:texture:file = @.\textures\color_121212.hdr@
+        float3 xformOp:rotateXYZ = (90, 1.2722219e-14, 90)
+        uniform token[] xformOpOrder = ["xformOp:rotateXYZ"]
+    }
+}
+
diff --git a/test/models-nonbsd/USD/usda/simple-skin-test.usda b/test/models-nonbsd/USD/usda/simple-skin-test.usda
new file mode 100644
index 000000000..501b79b72
--- /dev/null
+++ b/test/models-nonbsd/USD/usda/simple-skin-test.usda
@@ -0,0 +1,85 @@
+#usda 1.0
+(
+    defaultPrim = "root"
+    doc = "Blender v4.1.0"
+    metersPerUnit = 1
+    upAxis = "Z"
+)
+
+def Xform "root" (
+    customData = {
+        dictionary Blender = {
+            bool generated = 1
+        }
+    }
+)
+{
+    def SkelRoot "Armature"
+    {
+        matrix4d xformOp:transform = ( (1, 0, 0, 0), (0, -4.371138828673793e-8, -1, 0), (0, 1, -4.371138828673793e-8, 0), (0, -1.7017418146133423, 0, 1) )
+        uniform token[] xformOpOrder = ["xformOp:transform"]
+
+        def Skeleton "Armature" (
+            prepend apiSchemas = ["SkelBindingAPI"]
+        )
+        {
+            uniform matrix4d[] bindTransforms = [( (1, 0, 0, 0), (0, 0, 1, 0), (0, -1, 0, 0), (0, 0, 0, 1) ), ( (1, 0, 0, 0), (0, 0, 1, 0), (0, -1, 0, 0), (0, 0, 1, 1) )]
+            uniform token[] joints = ["Bone", "Bone/Bone_001"]
+            uniform matrix4d[] restTransforms = [( (1, 0, 0, 0), (0, 0, 1, 0), (0, -1, 0, 0), (0, 0, 0, 1) ), ( (1, 0, 0, 0), (0, 1, 0, 0), (0, 0, 1, 0), (0, 1, 0, 1) )]
+        }
+
+        def Xform "Grid"
+        {
+            matrix4d xformOp:transform = ( (1, 0, 0, 0), (0, -4.371138828673793e-8, 1, 0), (0, -1, -4.371138828673793e-8, 0), (0, -7.438549687321938e-8, 1.7017418146133423, 1) )
+            uniform token[] xformOpOrder = ["xformOp:transform"]
+
+            def Mesh "Grid" (
+                prepend apiSchemas = ["SkelBindingAPI"]
+            )
+            {
+                float3[] extent = [(-1, -1, 0), (1, 1, 0)]
+                int[] faceVertexCounts = [4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4]
+                int[] faceVertexIndices = [0, 1, 6, 5, 1, 2, 7, 6, 2, 3, 8, 7, 3, 4, 9, 8, 5, 6, 11, 10, 6, 7, 12, 11, 7, 8, 13, 12, 8, 9, 14, 13, 10, 11, 16, 15, 11, 12, 17, 16, 12, 13, 18, 17, 13, 14, 19, 18, 15, 16, 21, 20, 16, 17, 22, 21, 17, 18, 23, 22, 18, 19, 24, 23]
+                normal3f[] normals = [(0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1), (0, 0, 1)] (
+                    interpolation = "faceVarying"
+                )
+                point3f[] points = [(-1, -1, 0), (-0.5, -1, 0), (0, -1, 0), (0.5, -1, 0), (1, -1, 0), (-1, -0.5, 0), (-0.5, -0.5, 0), (0, -0.5, 0), (0.5, -0.5, 0), (1, -0.5, 0), (-1, 0, 0), (-0.5, 0, 0), (0, 0, 0), (0.5, 0, 0), (1, 0, 0), (-1, 0.5, 0), (-0.5, 0.5, 0), (0, 0.5, 0), (0.5, 0.5, 0), (1, 0.5, 0), (-1, 1, 0), (-0.5, 1, 0), (0, 1, 0), (0.5, 1, 0), (1, 1, 0)]
+                bool[] primvars:sharp_face = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1] (
+                    interpolation = "uniform"
+                )
+                matrix4d primvars:skel:geomBindTransform = ( (1, 0, 0, 0), (0, -4.371138828673793e-8, 1, 0), (0, -1, -4.371138828673793e-8, 0), (0, -7.438549687321938e-8, 1.7017418146133423, 1) )
+                int[] primvars:skel:jointIndices = [0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1] (
+                    elementSize = 2
+                    interpolation = "vertex"
+                )
+                float[] primvars:skel:jointWeights = [0.43767902, 0.56232095, 0.605441, 0.39455906, 1, 0, 0.605441, 0.39455906, 0.43767902, 0.562321, 0.23470172, 0.7652983, 0.18096954, 0.81903046, 1, 0, 0.18096954, 0.81903046, 0.23470171, 0.7652983, 0.114853, 0.88514704, 0.06506716, 0.9349329, 1, 0, 0.06506715, 0.9349329, 0.11485299, 0.88514704, 0.059175473, 0.94082457, 0.009479873, 0.9905201, 1, 0, 0.009479865, 0.9905201, 0.059175465, 0.94082457, 0.031181445, 0.96881855, 1, 0, 1, 0, 1, 0, 0.031181442, 0.9688186] (
+                    elementSize = 2
+                    interpolation = "vertex"
+                )
+                texCoord2f[] primvars:UVMap = [(0, 0), (0.25, 0), (0.25, 0.25), (0, 0.25), (0.25, 0), (0.5, 0), (0.5, 0.25), (0.25, 0.25), (0.5, 0), (0.75, 0), (0.75, 0.25), (0.5, 0.25), (0.75, 0), (1, 0), (1, 0.25), (0.75, 0.25), (0, 0.25), (0.25, 0.25), (0.25, 0.5), (0, 0.5), (0.25, 0.25), (0.5, 0.25), (0.5, 0.5), (0.25, 0.5), (0.5, 0.25), (0.75, 0.25), (0.75, 0.5), (0.5, 0.5), (0.75, 0.25), (1, 0.25), (1, 0.5), (0.75, 0.5), (0, 0.5), (0.25, 0.5), (0.25, 0.75), (0, 0.75), (0.25, 0.5), (0.5, 0.5), (0.5, 0.75), (0.25, 0.75), (0.5, 0.5), (0.75, 0.5), (0.75, 0.75), (0.5, 0.75), (0.75, 0.5), (1, 0.5), (1, 0.75), (0.75, 0.75), (0, 0.75), (0.25, 0.75), (0.25, 1), (0, 1), (0.25, 0.75), (0.5, 0.75), (0.5, 1), (0.25, 1), (0.5, 0.75), (0.75, 0.75), (0.75, 1), (0.5, 1), (0.75, 0.75), (1, 0.75), (1, 1), (0.75, 1)] (
+                    interpolation = "faceVarying"
+                )
+                rel skel:skeleton = </root/Armature/Armature>
+                uniform token subdivisionScheme = "none"
+            }
+        }
+    }
+
+    def Xform "Camera"
+    {
+        matrix4d xformOp:transform = ( (0.6859206557273865, 0.7276763319969177, 0, 0), (-0.32401347160339355, 0.305420845746994, 0.8953956365585327, 0), (0.6515582203865051, -0.6141703724861145, 0.44527140259742737, 0), (7.358891487121582, -6.925790786743164, 4.958309173583984, 1) )
+        uniform token[] xformOpOrder = ["xformOp:transform"]
+
+        def Camera "Camera"
+        {
+            float2 clippingRange = (0.1, 100)
+            float focalLength = 0.5
+            float horizontalAperture = 0.36
+            float horizontalApertureOffset = 0
+            token projection = "perspective"
+            float verticalAperture = 0.2025
+            float verticalApertureOffset = 0
+        }
+    }
+}
+
diff --git a/test/unit/utUSDImport.cpp b/test/unit/utUSDImport.cpp
index 2f4ffeaf4..c19ef2679 100644
--- a/test/unit/utUSDImport.cpp
+++ b/test/unit/utUSDImport.cpp
@@ -49,18 +49,42 @@ Copyright (c) 2006-2024, assimp team
 using namespace ::Assimp;
 
 class utUSDImport : public AbstractImportExportBase {
-public:
-    virtual bool importerTest() {
-        Assimp::Importer importer;
-        const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/../models-nonbsd/USD/suzanne.usdc", aiProcess_ValidateDataStructure);
-        EXPECT_EQ(1u, scene->mNumMeshes);
-        EXPECT_NE(nullptr, scene->mMeshes[0]);
-        if (nullptr == scene->mMeshes[0]) {
-            return false;
-        }
-        EXPECT_EQ(507u, scene->mMeshes[0]->mNumVertices);
-        EXPECT_EQ(968u, scene->mMeshes[0]->mNumFaces);
-
-        return (nullptr != scene);
-    }
 };
+
+TEST_F(utUSDImport, meshTest) {
+    Assimp::Importer importer;
+    const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/../models-nonbsd/USD/usdc/suzanne.usdc", aiProcess_ValidateDataStructure);
+    EXPECT_NE(nullptr, scene);
+    EXPECT_EQ(1u, scene->mNumMeshes);
+    EXPECT_NE(nullptr, scene->mMeshes[0]);
+    EXPECT_EQ(1968u, scene->mMeshes[0]->mNumVertices); // Note: suzanne is authored with only 507 vertices, but TinyUSDZ rebuilds the vertex array. see https://github.com/lighttransport/tinyusdz/blob/36f2aabb256b360365989c01a52f839a57dfe2a6/src/tydra/render-data.cc#L2673-L2690 
+    EXPECT_EQ(968u, scene->mMeshes[0]->mNumFaces);
+}
+
+TEST_F(utUSDImport, skinnedMeshTest) {
+    Assimp::Importer importer;
+    const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/../models-nonbsd/USD/usda/simple-skin-test.usda", aiProcess_ValidateDataStructure);
+    EXPECT_NE(nullptr, scene);
+    EXPECT_TRUE(scene->HasMeshes());
+
+    const aiMesh *mesh = scene->mMeshes[0];
+    EXPECT_EQ(2, mesh->mNumBones);
+
+    // Check bone names and make sure scene has nodes of the same name
+    EXPECT_EQ(mesh->mBones[0]->mName, aiString("Bone"));
+    EXPECT_EQ(mesh->mBones[1]->mName, aiString("Bone/Bone_001"));
+
+    EXPECT_NE(nullptr, scene->mRootNode->FindNode("Bone"));
+    EXPECT_NE(nullptr, scene->mRootNode->FindNode("Bone/Bone_001"));
+}
+
+TEST_F(utUSDImport, singleAnimationTest) {
+    Assimp::Importer importer;
+    const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/../models-nonbsd/USD/usda/simple-skin-animation-test.usda", aiProcess_ValidateDataStructure);
+    EXPECT_NE(nullptr, scene);
+    EXPECT_TRUE(scene->HasAnimations());
+    EXPECT_EQ(2, scene->mAnimations[0]->mNumChannels);  // 2 bones. 1 channel for each bone
+}
+
+// Note: Add multi-animation test once supported by USD
+// See https://github.com/lighttransport/tinyusdz/issues/122 for details.