diff --git a/assignment-client/src/entities/AssignmentParentFinder.cpp b/assignment-client/src/entities/AssignmentParentFinder.cpp
index 294556383e..a0232daff4 100644
--- a/assignment-client/src/entities/AssignmentParentFinder.cpp
+++ b/assignment-client/src/entities/AssignmentParentFinder.cpp
@@ -11,7 +11,7 @@
 
 #include "AssignmentParentFinder.h"
 
-SpatiallyNestableWeakPointer AssignmentParentFinder::find(QUuid parentID, bool& success) const {
+SpatiallyNestableWeakPointer AssignmentParentFinder::find(QUuid parentID, bool& success, SpatialParentTree* entityTree) const {
     SpatiallyNestableWeakPointer parent;
 
     if (parentID.isNull()) {
@@ -20,7 +20,11 @@ SpatiallyNestableWeakPointer AssignmentParentFinder::find(QUuid parentID, bool&
     }
 
     // search entities
-    parent = _tree->findEntityByEntityItemID(parentID);
+    if (entityTree) {
+        parent = entityTree->findByID(parentID);
+    } else {
+        parent = _tree->findEntityByEntityItemID(parentID);
+    }
     if (parent.expired()) {
         success = false;
     } else {
diff --git a/assignment-client/src/entities/AssignmentParentFinder.h b/assignment-client/src/entities/AssignmentParentFinder.h
index 9a776bc7dd..0c16143143 100644
--- a/assignment-client/src/entities/AssignmentParentFinder.h
+++ b/assignment-client/src/entities/AssignmentParentFinder.h
@@ -25,7 +25,7 @@ class AssignmentParentFinder : public SpatialParentFinder {
 public:
     AssignmentParentFinder(EntityTreePointer tree) : _tree(tree) { }
     virtual ~AssignmentParentFinder() { }
-    virtual SpatiallyNestableWeakPointer find(QUuid parentID, bool& success) const;
+    virtual SpatiallyNestableWeakPointer find(QUuid parentID, bool& success, SpatialParentTree* entityTree = nullptr) const;
 
 protected:
     EntityTreePointer _tree;
diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index c6669303a8..de9b134b83 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -598,8 +598,18 @@ Application::Application(int& argc, char** argv, QElapsedTimer& startupTimer) :
     audioThread->setObjectName("Audio Thread");
 
     auto audioIO = DependencyManager::get<AudioClient>();
-    audioIO->setPositionGetter([this]{ return getMyAvatar()->getPositionForAudio(); });
-    audioIO->setOrientationGetter([this]{ return getMyAvatar()->getOrientationForAudio(); });
+    audioIO->setPositionGetter([]{
+        auto avatarManager = DependencyManager::get<AvatarManager>();
+        auto myAvatar = avatarManager ? avatarManager->getMyAvatar() : nullptr;
+        
+        return myAvatar ? myAvatar->getPositionForAudio() : Vectors::ZERO;
+    });
+    audioIO->setOrientationGetter([]{
+        auto avatarManager = DependencyManager::get<AvatarManager>();
+        auto myAvatar = avatarManager ? avatarManager->getMyAvatar() : nullptr;
+
+        return myAvatar ? myAvatar->getOrientationForAudio() : Quaternions::IDENTITY;
+    });
 
     audioIO->moveToThread(audioThread);
     recording::Frame::registerFrameHandler(AudioConstants::getAudioFrameName(), [=](recording::Frame::ConstPointer frame) {
@@ -2790,43 +2800,50 @@ void Application::calibrateEyeTracker5Points() {
 }
 #endif
 
-bool Application::exportEntities(const QString& filename, const QVector<EntityItemID>& entityIDs) {
-    QVector<EntityItemPointer> entities;
+bool Application::exportEntities(const QString& filename, const QVector<EntityItemID>& entityIDs, const glm::vec3* givenOffset) {
+    QHash<EntityItemID, EntityItemPointer> entities;
 
     auto entityTree = getEntities()->getTree();
     auto exportTree = std::make_shared<EntityTree>();
     exportTree->createRootElement();
 
     glm::vec3 root(TREE_SCALE, TREE_SCALE, TREE_SCALE);
-    for (auto entityID : entityIDs) {
+    for (auto entityID : entityIDs) { // Gather entities and properties.
         auto entityItem = entityTree->findEntityByEntityItemID(entityID);
         if (!entityItem) {
+            qCWarning(interfaceapp) << "Skipping export of" << entityID << "that is not in scene.";
             continue;
         }
 
-        auto properties = entityItem->getProperties();
-        auto position = properties.getPosition();
-
-        root.x = glm::min(root.x, position.x);
-        root.y = glm::min(root.y, position.y);
-        root.z = glm::min(root.z, position.z);
-
-        entities << entityItem;
+        if (!givenOffset) {
+            EntityItemID parentID = entityItem->getParentID();
+            if (parentID.isInvalidID() || !entityIDs.contains(parentID) || !entityTree->findEntityByEntityItemID(parentID)) {
+                auto position = entityItem->getPosition(); // If parent wasn't selected, we want absolute position, which isn't in properties.
+                root.x = glm::min(root.x, position.x);
+                root.y = glm::min(root.y, position.y);
+                root.z = glm::min(root.z, position.z);
+            }
+        }
+        entities[entityID] = entityItem;
     }
 
     if (entities.size() == 0) {
         return false;
     }
 
-    for (auto entityItem : entities) {
-        auto properties = entityItem->getProperties();
-
-        properties.setPosition(properties.getPosition() - root);
-        exportTree->addEntity(entityItem->getEntityItemID(), properties);
+    if (givenOffset) {
+        root = *givenOffset;
+    }
+    for (EntityItemPointer& entityDatum : entities) {
+        auto properties = entityDatum->getProperties();
+        EntityItemID parentID = properties.getParentID();
+        if (parentID.isInvalidID()) {
+            properties.setPosition(properties.getPosition() - root);
+        } else if (!entities.contains(parentID)) {
+            entityDatum->globalizeProperties(properties, "Parent %3 of %2 %1 is not selected for export.", -root);
+        } // else valid parent -- don't offset
+        exportTree->addEntity(entityDatum->getEntityItemID(), properties);
     }
-
-    // remap IDs on export so that we aren't publishing the IDs of entities in our domain
-    exportTree->remapIDs();
 
     exportTree->writeToJSONFile(filename.toLocal8Bit().constData());
 
@@ -2836,33 +2853,14 @@ bool Application::exportEntities(const QString& filename, const QVector<EntityIt
 }
 
 bool Application::exportEntities(const QString& filename, float x, float y, float z, float scale) {
+    glm::vec3 offset(x, y, z);
     QVector<EntityItemPointer> entities;
-    getEntities()->getTree()->findEntities(AACube(glm::vec3(x, y, z), scale), entities);
-
-    if (entities.size() > 0) {
-        glm::vec3 root(x, y, z);
-        auto exportTree = std::make_shared<EntityTree>();
-        exportTree->createRootElement();
-
-        for (int i = 0; i < entities.size(); i++) {
-            EntityItemProperties properties = entities.at(i)->getProperties();
-            EntityItemID id = entities.at(i)->getEntityItemID();
-            properties.setPosition(properties.getPosition() - root);
-            exportTree->addEntity(id, properties);
-        }
-
-        // remap IDs on export so that we aren't publishing the IDs of entities in our domain
-        exportTree->remapIDs();
-
-        exportTree->writeToSVOFile(filename.toLocal8Bit().constData());
-    } else {
-        qCDebug(interfaceapp) << "No models were selected";
-        return false;
+    QVector<EntityItemID> ids;
+    getEntities()->getTree()->findEntities(AACube(offset, scale), entities);
+    foreach(EntityItemPointer entity, entities) {
+        ids << entity->getEntityItemID();
     }
-
-    // restore the main window's active state
-    _window->activateWindow();
-    return true;
+    return exportEntities(filename, ids, &offset);
 }
 
 void Application::loadSettings() {
@@ -2895,7 +2893,6 @@ bool Application::importEntities(const QString& urlOrFilename) {
 
     bool success = _entityClipboard->readFromURL(urlOrFilename);
     if (success) {
-        _entityClipboard->remapIDs();
         _entityClipboard->reaverageOctreeElements();
     }
     return success;
@@ -2978,6 +2975,11 @@ void Application::updateLOD() {
     }
 }
 
+void Application::pushPreRenderLambda(void* key, std::function<void()> func) {
+    std::unique_lock<std::mutex> guard(_preRenderLambdasLock);
+    _preRenderLambdas[key] = func;
+}
+
 // Called during Application::update immediately before AvatarManager::updateMyAvatar, updating my data that is then sent to everyone.
 // (Maybe this code should be moved there?)
 // The principal result is to call updateLookAtTargetAvatar() and then setLookAtPosition().
@@ -3454,6 +3456,16 @@ void Application::update(float deltaTime) {
             QMetaObject::invokeMethod(DependencyManager::get<AudioClient>().data(), "sendDownstreamAudioStatsPacket", Qt::QueuedConnection);
         }
     }
+
+    {
+        PROFILE_RANGE_EX("PreRenderLambdas", 0xffff0000, (uint64_t)0);
+
+        std::unique_lock<std::mutex> guard(_preRenderLambdasLock);
+        for (auto& iter : _preRenderLambdas) {
+            iter.second();
+        }
+        _preRenderLambdas.clear();
+    }
 }
 
 
diff --git a/interface/src/Application.h b/interface/src/Application.h
index d21e647bc7..31c865ad90 100644
--- a/interface/src/Application.h
+++ b/interface/src/Application.h
@@ -211,6 +211,8 @@ public:
     render::EnginePointer getRenderEngine() override { return _renderEngine; }
     gpu::ContextPointer getGPUContext() const { return _gpuContext; }
 
+    virtual void pushPreRenderLambda(void* key, std::function<void()> func) override;
+
     const QRect& getMirrorViewRect() const { return _mirrorViewRect; }
 
     void updateMyAvatarLookAtPosition();
@@ -233,7 +235,7 @@ signals:
 
 public slots:
     QVector<EntityItemID> pasteEntities(float x, float y, float z);
-    bool exportEntities(const QString& filename, const QVector<EntityItemID>& entityIDs);
+    bool exportEntities(const QString& filename, const QVector<EntityItemID>& entityIDs, const glm::vec3* givenOffset = nullptr);
     bool exportEntities(const QString& filename, float x, float y, float z, float scale);
     bool importEntities(const QString& url);
 
@@ -510,6 +512,9 @@ private:
     bool _cursorNeedsChanging { false };
 
     QThread* _deadlockWatchdogThread;
+
+    std::map<void*, std::function<void()>> _preRenderLambdas;
+    std::mutex _preRenderLambdasLock;
 };
 
 #endif // hifi_Application_h
diff --git a/interface/src/InterfaceParentFinder.cpp b/interface/src/InterfaceParentFinder.cpp
index de4b0ce38c..b1db63debd 100644
--- a/interface/src/InterfaceParentFinder.cpp
+++ b/interface/src/InterfaceParentFinder.cpp
@@ -16,7 +16,7 @@
 
 #include "InterfaceParentFinder.h"
 
-SpatiallyNestableWeakPointer InterfaceParentFinder::find(QUuid parentID, bool& success) const {
+SpatiallyNestableWeakPointer InterfaceParentFinder::find(QUuid parentID, bool& success, SpatialParentTree* entityTree) const {
     SpatiallyNestableWeakPointer parent;
 
     if (parentID.isNull()) {
@@ -25,9 +25,13 @@ SpatiallyNestableWeakPointer InterfaceParentFinder::find(QUuid parentID, bool& s
     }
 
     // search entities
-    EntityTreeRenderer* treeRenderer = qApp->getEntities();
-    EntityTreePointer tree = treeRenderer ? treeRenderer->getTree() : nullptr;
-    parent = tree ? tree->findEntityByEntityItemID(parentID) : nullptr;
+    if (entityTree) {
+        parent = entityTree->findByID(parentID);
+    } else {
+        EntityTreeRenderer* treeRenderer = qApp->getEntities();
+        EntityTreePointer tree = treeRenderer ? treeRenderer->getTree() : nullptr;
+        parent = tree ? tree->findEntityByEntityItemID(parentID) : nullptr;
+    }
     if (!parent.expired()) {
         success = true;
         return parent;
diff --git a/interface/src/InterfaceParentFinder.h b/interface/src/InterfaceParentFinder.h
index db579c2144..a2e9fb50e4 100644
--- a/interface/src/InterfaceParentFinder.h
+++ b/interface/src/InterfaceParentFinder.h
@@ -21,7 +21,7 @@ class InterfaceParentFinder : public SpatialParentFinder {
 public:
     InterfaceParentFinder() { }
     virtual ~InterfaceParentFinder() { }
-    virtual SpatiallyNestableWeakPointer find(QUuid parentID, bool& success) const;
+    virtual SpatiallyNestableWeakPointer find(QUuid parentID, bool& success, SpatialParentTree* entityTree = nullptr) const;
 };
 
 #endif // hifi_InterfaceParentFinder_h
diff --git a/interface/src/ui/overlays/ModelOverlay.cpp b/interface/src/ui/overlays/ModelOverlay.cpp
index 010698800b..adf08934f0 100644
--- a/interface/src/ui/overlays/ModelOverlay.cpp
+++ b/interface/src/ui/overlays/ModelOverlay.cpp
@@ -18,22 +18,22 @@
 QString const ModelOverlay::TYPE = "model";
 
 ModelOverlay::ModelOverlay()
-    : _model(std::make_shared<Rig>()),
+    : _model(std::make_shared<Model>(std::make_shared<Rig>())),
       _modelTextures(QVariantMap()),
       _updateModel(false)
 {
-    _model.init();
+    _model->init();
     _isLoaded = false;
 }
 
 ModelOverlay::ModelOverlay(const ModelOverlay* modelOverlay) :
     Volume3DOverlay(modelOverlay),
-    _model(std::make_shared<Rig>()),
+    _model(std::make_shared<Model>(std::make_shared<Rig>())),
     _modelTextures(QVariantMap()),
     _url(modelOverlay->_url),
     _updateModel(false)
 {
-    _model.init();
+    _model->init();
     if (_url.isValid()) {
         _updateModel = true;
         _isLoaded = false;
@@ -44,27 +44,27 @@ void ModelOverlay::update(float deltatime) {
     if (_updateModel) {
         _updateModel = false;
         
-        _model.setSnapModelToCenter(true);
-        _model.setScale(getDimensions());
-        _model.setRotation(getRotation());
-        _model.setTranslation(getPosition());
-        _model.setURL(_url);
-        _model.simulate(deltatime, true);
+        _model->setSnapModelToCenter(true);
+        _model->setScale(getDimensions());
+        _model->setRotation(getRotation());
+        _model->setTranslation(getPosition());
+        _model->setURL(_url);
+        _model->simulate(deltatime, true);
     } else {
-        _model.simulate(deltatime);
+        _model->simulate(deltatime);
     }
-    _isLoaded = _model.isActive();
+    _isLoaded = _model->isActive();
 }
 
 bool ModelOverlay::addToScene(Overlay::Pointer overlay, std::shared_ptr<render::Scene> scene, render::PendingChanges& pendingChanges) {
     Volume3DOverlay::addToScene(overlay, scene, pendingChanges);
-    _model.addToScene(scene, pendingChanges);
+    _model->addToScene(scene, pendingChanges);
     return true;
 }
 
 void ModelOverlay::removeFromScene(Overlay::Pointer overlay, std::shared_ptr<render::Scene> scene, render::PendingChanges& pendingChanges) {
     Volume3DOverlay::removeFromScene(overlay, scene, pendingChanges);
-    _model.removeFromScene(scene, pendingChanges);
+    _model->removeFromScene(scene, pendingChanges);
 }
 
 void ModelOverlay::render(RenderArgs* args) {
@@ -73,9 +73,9 @@ void ModelOverlay::render(RenderArgs* args) {
     // fix them up in the scene
     render::ScenePointer scene = qApp->getMain3DScene();
     render::PendingChanges pendingChanges;
-    if (_model.needsFixupInScene()) {
-        _model.removeFromScene(scene, pendingChanges);
-        _model.addToScene(scene, pendingChanges);
+    if (_model->needsFixupInScene()) {
+        _model->removeFromScene(scene, pendingChanges);
+        _model->addToScene(scene, pendingChanges);
     }
     scene->enqueuePendingChanges(pendingChanges);
 
@@ -100,7 +100,7 @@ void ModelOverlay::setProperties(const QVariantMap& properties) {
         if (newScale.x <= 0 || newScale.y <= 0 || newScale.z <= 0) {
             setDimensions(scale);
         } else {
-            _model.setScaleToFit(true, getDimensions());
+            _model->setScaleToFit(true, getDimensions());
             _updateModel = true;
         }
     }
@@ -120,7 +120,7 @@ void ModelOverlay::setProperties(const QVariantMap& properties) {
             QUrl newTextureURL = textureMap[key].toUrl();
             qDebug() << "Updating texture named" << key << "to texture at URL" << newTextureURL;
             
-            QMetaObject::invokeMethod(&_model, "setTextureWithNameToURL", Qt::AutoConnection,
+            QMetaObject::invokeMethod(_model.get(), "setTextureWithNameToURL", Qt::AutoConnection,
                                       Q_ARG(const QString&, key),
                                       Q_ARG(const QUrl&, newTextureURL));
 
@@ -134,7 +134,7 @@ QVariant ModelOverlay::getProperty(const QString& property) {
         return _url.toString();
     }
     if (property == "dimensions" || property == "scale" || property == "size") {
-        return vec3toVariant(_model.getScaleToFitDimensions());
+        return vec3toVariant(_model->getScaleToFitDimensions());
     }
     if (property == "textures") {
         if (_modelTextures.size() > 0) {
@@ -155,13 +155,13 @@ bool ModelOverlay::findRayIntersection(const glm::vec3& origin, const glm::vec3&
                                         float& distance, BoxFace& face, glm::vec3& surfaceNormal) {
     
     QString subMeshNameTemp;
-    return _model.findRayIntersectionAgainstSubMeshes(origin, direction, distance, face, surfaceNormal, subMeshNameTemp);
+    return _model->findRayIntersectionAgainstSubMeshes(origin, direction, distance, face, surfaceNormal, subMeshNameTemp);
 }
 
 bool ModelOverlay::findRayIntersectionExtraInfo(const glm::vec3& origin, const glm::vec3& direction,
                                         float& distance, BoxFace& face, glm::vec3& surfaceNormal, QString& extraInfo) {
     
-    return _model.findRayIntersectionAgainstSubMeshes(origin, direction, distance, face, surfaceNormal, extraInfo);
+    return _model->findRayIntersectionAgainstSubMeshes(origin, direction, distance, face, surfaceNormal, extraInfo);
 }
 
 ModelOverlay* ModelOverlay::createClone() const {
diff --git a/interface/src/ui/overlays/ModelOverlay.h b/interface/src/ui/overlays/ModelOverlay.h
index 0b67f7ed37..36ff75cb6a 100644
--- a/interface/src/ui/overlays/ModelOverlay.h
+++ b/interface/src/ui/overlays/ModelOverlay.h
@@ -41,11 +41,11 @@ public:
 
 private:
 
-    Model _model;
+    ModelPointer _model;
     QVariantMap _modelTextures;
     
     QUrl _url;
     bool _updateModel;
 };
 
-#endif // hifi_ModelOverlay_h
\ No newline at end of file
+#endif // hifi_ModelOverlay_h
diff --git a/libraries/animation/src/Rig.cpp b/libraries/animation/src/Rig.cpp
index a2b664d064..6a8f190808 100644
--- a/libraries/animation/src/Rig.cpp
+++ b/libraries/animation/src/Rig.cpp
@@ -1056,7 +1056,9 @@ void Rig::updateEyeJoint(int index, const glm::vec3& modelTranslation, const glm
 
         // limit rotation
         const float MAX_ANGLE = 30.0f * RADIANS_PER_DEGREE;
-        deltaQuat = glm::angleAxis(glm::clamp(glm::angle(deltaQuat), -MAX_ANGLE, MAX_ANGLE), glm::axis(deltaQuat));
+        if (fabsf(glm::angle(deltaQuat)) > MAX_ANGLE) {
+            deltaQuat = glm::angleAxis(glm::clamp(glm::angle(deltaQuat), -MAX_ANGLE, MAX_ANGLE), glm::axis(deltaQuat));
+        }
 
         // directly set absolutePose rotation
         _internalPoseSet._absolutePoses[index].rot = deltaQuat * headQuat;
diff --git a/libraries/animation/src/Rig.h b/libraries/animation/src/Rig.h
index 1f9a02d8ab..3a27b9304b 100644
--- a/libraries/animation/src/Rig.h
+++ b/libraries/animation/src/Rig.h
@@ -221,6 +221,8 @@ public:
 
     void setEnableInverseKinematics(bool enable);
 
+    const glm::mat4& getGeometryToRigTransform() const { return _geometryToRigTransform; }
+
  protected:
     bool isIndexValid(int index) const { return _animSkeleton && index >= 0 && index < _animSkeleton->getNumJoints(); }
     void updateAnimationStateHandlers();
diff --git a/libraries/audio-client/src/AudioClient.cpp b/libraries/audio-client/src/AudioClient.cpp
index 7e01196dc7..50e5b7591f 100644
--- a/libraries/audio-client/src/AudioClient.cpp
+++ b/libraries/audio-client/src/AudioClient.cpp
@@ -50,6 +50,9 @@
 
 static const int RECEIVED_AUDIO_STREAM_CAPACITY_FRAMES = 100;
 
+static const auto DEFAULT_POSITION_GETTER = []{ return Vectors::ZERO; };
+static const auto DEFAULT_ORIENTATION_GETTER = [] { return Quaternions::IDENTITY; };
+
 Setting::Handle<bool> dynamicJitterBuffers("dynamicJitterBuffers", DEFAULT_DYNAMIC_JITTER_BUFFERS);
 Setting::Handle<int> maxFramesOverDesired("maxFramesOverDesired", DEFAULT_MAX_FRAMES_OVER_DESIRED);
 Setting::Handle<int> staticDesiredJitterBufferFrames("staticDesiredJitterBufferFrames",
@@ -103,7 +106,9 @@ AudioClient::AudioClient() :
     _outgoingAvatarAudioSequenceNumber(0),
     _audioOutputIODevice(_receivedAudioStream, this),
     _stats(&_receivedAudioStream),
-    _inputGate()
+    _inputGate(),
+    _positionGetter(DEFAULT_POSITION_GETTER),
+    _orientationGetter(DEFAULT_ORIENTATION_GETTER)
 {
     // clear the array of locally injected samples
     memset(_localProceduralSamples, 0, AudioConstants::NETWORK_FRAME_BYTES_PER_CHANNEL);
diff --git a/libraries/entities-renderer/src/EntityTreeRenderer.cpp b/libraries/entities-renderer/src/EntityTreeRenderer.cpp
index 07d19dbd92..65ac5197c8 100644
--- a/libraries/entities-renderer/src/EntityTreeRenderer.cpp
+++ b/libraries/entities-renderer/src/EntityTreeRenderer.cpp
@@ -460,14 +460,17 @@ void EntityTreeRenderer::processEraseMessage(ReceivedMessage& message, const Sha
 
 ModelPointer EntityTreeRenderer::allocateModel(const QString& url, const QString& collisionUrl) {
     ModelPointer model = nullptr;
-    // Make sure we only create and delete models on the thread that owns the EntityTreeRenderer
+
+    // Only create and delete models on the thread that owns the EntityTreeRenderer
     if (QThread::currentThread() != thread()) {
         QMetaObject::invokeMethod(this, "allocateModel", Qt::BlockingQueuedConnection,
                 Q_RETURN_ARG(ModelPointer, model),
-                Q_ARG(const QString&, url));
+                Q_ARG(const QString&, url),
+                Q_ARG(const QString&, collisionUrl));
 
         return model;
     }
+
     model = std::make_shared<Model>(std::make_shared<Rig>());
     model->init();
     model->setURL(QUrl(url));
@@ -475,37 +478,20 @@ ModelPointer EntityTreeRenderer::allocateModel(const QString& url, const QString
     return model;
 }
 
-ModelPointer EntityTreeRenderer::updateModel(ModelPointer original, const QString& newUrl, const QString& collisionUrl) {
-    ModelPointer model = nullptr;
-
-    // The caller shouldn't call us if the URL doesn't need to change. But if they
-    // do, we just return their original back to them.
-    if (!original || (QUrl(newUrl) == original->getURL())) {
-        return original;
-    }
-
-    // Before we do any creating or deleting, make sure we're on our renderer thread
+ModelPointer EntityTreeRenderer::updateModel(ModelPointer model, const QString& newUrl, const QString& collisionUrl) {
+    // Only create and delete models on the thread that owns the EntityTreeRenderer
     if (QThread::currentThread() != thread()) {
         QMetaObject::invokeMethod(this, "updateModel", Qt::BlockingQueuedConnection,
             Q_RETURN_ARG(ModelPointer, model),
-                Q_ARG(ModelPointer, original),
-                Q_ARG(const QString&, newUrl));
+                Q_ARG(ModelPointer, model),
+                Q_ARG(const QString&, newUrl),
+                Q_ARG(const QString&, collisionUrl));
 
         return model;
     }
 
-    // at this point we know we need to replace the model, and we know we're on the
-    // correct thread, so we can do all our work.
-    if (original) {
-        original.reset(); // delete the old model...
-    }
-
-    // create the model and correctly initialize it with the new url
-    model = std::make_shared<Model>(std::make_shared<Rig>());
-    model->init();
     model->setURL(QUrl(newUrl));
     model->setCollisionModelURL(QUrl(collisionUrl));
-        
     return model;
 }
 
diff --git a/libraries/entities-renderer/src/RenderableModelEntityItem.cpp b/libraries/entities-renderer/src/RenderableModelEntityItem.cpp
index ae29d1faf7..13942dc282 100644
--- a/libraries/entities-renderer/src/RenderableModelEntityItem.cpp
+++ b/libraries/entities-renderer/src/RenderableModelEntityItem.cpp
@@ -69,14 +69,10 @@ void RenderableModelEntityItem::loader() {
     _needsModelReload = true;
     EntityTreeRenderer* renderer = DependencyManager::get<EntityTreeRenderer>().data();
     assert(renderer);
-    if (!_model || _needsModelReload) {
+    {
         PerformanceTimer perfTimer("getModel");
         getModel(renderer);
     }
-    if (_model) {
-        _model->setURL(getParsedModelURL());
-        _model->setCollisionModelURL(QUrl(getCompoundShapeURL()));
-    }
 }
 
 void RenderableModelEntityItem::setDimensions(const glm::vec3& value) {
@@ -109,7 +105,7 @@ int RenderableModelEntityItem::readEntitySubclassDataFromBuffer(const unsigned c
 
 QVariantMap RenderableModelEntityItem::parseTexturesToMap(QString textures) {
     // If textures are unset, revert to original textures
-    if (textures == "") {
+    if (textures.isEmpty()) {
         return _originalTextures;
     }
 
@@ -124,7 +120,9 @@ QVariantMap RenderableModelEntityItem::parseTexturesToMap(QString textures) {
         qCWarning(entitiesrenderer) << "Could not evaluate textures property value:" << _textures;
         return _originalTextures;
     }
-    return texturesJson.object().toVariantMap();
+
+    auto parsed = texturesJson.toVariant();
+    return parsed.toMap();
 }
 
 void RenderableModelEntityItem::remapTextures() {
@@ -364,13 +362,6 @@ void RenderableModelEntityItem::render(RenderArgs* args) {
 
     if (hasModel()) {
         if (_model) {
-            // check if the URL has changed
-            auto& currentURL = getParsedModelURL();
-            if (currentURL != _model->getURL()) {
-                qCDebug(entitiesrenderer).noquote() << "Updating model URL: " << currentURL.toDisplayString();
-                _model->setURL(currentURL);
-            }
-
             render::ScenePointer scene = AbstractViewStateInterface::instance()->getMain3DScene();
 
             // check to see if when we added our models to the scene they were ready, if they were not ready, then
@@ -435,6 +426,15 @@ void RenderableModelEntityItem::render(RenderArgs* args) {
                     }
                 });
                 updateModelBounds();
+
+                // Check if the URL has changed
+                // Do this last as the getModel is queued for the next frame,
+                // and we need to keep state directing the model to reinitialize
+                auto& currentURL = getParsedModelURL();
+                if (currentURL != _model->getURL()) {
+                    // Defer setting the url to the render thread
+                    getModel(_myRenderer);
+                }
             }
         }
     } else {
@@ -450,10 +450,8 @@ void RenderableModelEntityItem::render(RenderArgs* args) {
 }
 
 ModelPointer RenderableModelEntityItem::getModel(EntityTreeRenderer* renderer) {
-    ModelPointer result = nullptr;
-
     if (!renderer) {
-        return result;
+        return nullptr;
     }
 
     // make sure our renderer is setup
@@ -468,21 +466,22 @@ ModelPointer RenderableModelEntityItem::getModel(EntityTreeRenderer* renderer) {
     
     _needsModelReload = false; // this is the reload
 
-    // if we have a URL, then we will want to end up returning a model...
+    // If we have a URL, then we will want to end up returning a model...
     if (!getModelURL().isEmpty()) {
-    
-        // if we have a previously allocated model, but its URL doesn't match
-        // then we need to let our renderer update our model for us.
-        if (_model && (QUrl(getModelURL()) != _model->getURL() ||
-                       QUrl(getCompoundShapeURL()) != _model->getCollisionURL())) {
-            result = _model = _myRenderer->updateModel(_model, getModelURL(), getCompoundShapeURL());
+        // If we don't have a model, allocate one *immediately*
+        if (!_model) {
+            _model = _myRenderer->allocateModel(getModelURL(), getCompoundShapeURL());
             _needsInitialSimulation = true;
-        } else if (!_model) { // if we don't yet have a model, then we want our renderer to allocate one
-            result = _model = _myRenderer->allocateModel(getModelURL(), getCompoundShapeURL());
+        // If we need to change URLs, update it *after rendering* (to avoid access violations)
+        } else if ((QUrl(getModelURL()) != _model->getURL() || QUrl(getCompoundShapeURL()) != _model->getCollisionURL())) {
+            QMetaObject::invokeMethod(_myRenderer, "updateModel", Qt::QueuedConnection,
+                Q_ARG(ModelPointer, _model),
+                Q_ARG(const QString&, getModelURL()),
+                Q_ARG(const QString&, getCompoundShapeURL()));
             _needsInitialSimulation = true;
-        } else { // we already have the model we want...
-            result = _model;
         }
+        // Else we can just return the _model
+    // If we have no URL, then we can delete any model we do have...
     } else if (_model) {
         // remove from scene
         render::ScenePointer scene = AbstractViewStateInterface::instance()->getMain3DScene();
@@ -492,11 +491,11 @@ ModelPointer RenderableModelEntityItem::getModel(EntityTreeRenderer* renderer) {
 
         // release interest
         _myRenderer->releaseModel(_model);
-        result = _model = nullptr;
+        _model = nullptr;
         _needsInitialSimulation = true;
     }
 
-    return result;
+    return _model;
 }
 
 bool RenderableModelEntityItem::needsToCallUpdate() const {
diff --git a/libraries/entities-renderer/src/RenderableWebEntityItem.cpp b/libraries/entities-renderer/src/RenderableWebEntityItem.cpp
index ce3faeb196..855fd16408 100644
--- a/libraries/entities-renderer/src/RenderableWebEntityItem.cpp
+++ b/libraries/entities-renderer/src/RenderableWebEntityItem.cpp
@@ -55,8 +55,8 @@ bool RenderableWebEntityItem::buildWebSurface(EntityTreeRenderer* renderer) {
         qWarning() << "Too many concurrent web views to create new view";
         return false;
     }
-
     qDebug() << "Building web surface";
+
     ++_currentWebCount;
     // Save the original GL context, because creating a QML surface will create a new context
     QOpenGLContext * currentContext = QOpenGLContext::currentContext();
diff --git a/libraries/entities/src/EntityItem.cpp b/libraries/entities/src/EntityItem.cpp
index bbc94e9910..431d638063 100644
--- a/libraries/entities/src/EntityItem.cpp
+++ b/libraries/entities/src/EntityItem.cpp
@@ -1010,6 +1010,10 @@ EntityTreePointer EntityItem::getTree() const {
     return tree;
 }
 
+SpatialParentTree* EntityItem::getParentTree() const {
+    return getTree().get();
+}
+
 bool EntityItem::wantTerseEditLogging() const {
     EntityTreePointer tree = getTree();
     return tree ? tree->wantTerseEditLogging() : false;
@@ -1978,3 +1982,25 @@ void EntityItem::dimensionsChanged() {
     requiresRecalcBoxes();
     SpatiallyNestable::dimensionsChanged(); // Do what you have to do
 }
+
+void EntityItem::globalizeProperties(EntityItemProperties& properties, const QString& messageTemplate, const glm::vec3& offset) const {
+    bool success;
+    auto globalPosition = getPosition(success);
+    if (success) {
+        properties.setPosition(globalPosition + offset);
+        properties.setRotation(getRotation());
+        properties.setDimensions(getDimensions());
+        // Should we do velocities and accelerations, too? This could end up being quite involved, which is why the method exists.
+    } else {
+        properties.setPosition(getQueryAACube().calcCenter() + offset); // best we can do
+    }
+    if (!messageTemplate.isEmpty()) {
+        QString name = properties.getName();
+        if (name.isEmpty()) {
+            name = EntityTypes::getEntityTypeName(properties.getType());
+        }
+        qCWarning(entities) << messageTemplate.arg(getEntityItemID().toString()).arg(name).arg(properties.getParentID().toString());
+    }
+    QUuid empty;
+    properties.setParentID(empty);
+}
diff --git a/libraries/entities/src/EntityItem.h b/libraries/entities/src/EntityItem.h
index 577bb406bc..622f78b2d3 100644
--- a/libraries/entities/src/EntityItem.h
+++ b/libraries/entities/src/EntityItem.h
@@ -86,6 +86,8 @@ public:
 
     /// returns true if something changed
     virtual bool setProperties(const EntityItemProperties& properties);
+    // Update properties with empty parent id and globalized/absolute values (applying offset), and apply (non-empty) log template to args id, name-or-type, parent id.
+    void globalizeProperties(EntityItemProperties& properties, const QString& messageTemplate = QString(), const glm::vec3& offset = glm::vec3(0.0f)) const;
 
     /// Override this in your derived class if you'd like to be informed when something about the state of the entity
     /// has changed. This will be called with properties change or when new data is loaded from a stream
@@ -359,6 +361,7 @@ public:
     void setPhysicsInfo(void* data) { _physicsInfo = data; }
     EntityTreeElementPointer getElement() const { return _element; }
     EntityTreePointer getTree() const;
+    virtual SpatialParentTree* getParentTree() const;
     bool wantTerseEditLogging() const;
 
     glm::mat4 getEntityToWorldMatrix() const;
diff --git a/libraries/entities/src/EntityTree.cpp b/libraries/entities/src/EntityTree.cpp
index af1c2e71aa..5292e12ae8 100644
--- a/libraries/entities/src/EntityTree.cpp
+++ b/libraries/entities/src/EntityTree.cpp
@@ -24,7 +24,6 @@
 #include "EntitiesLogging.h"
 #include "RecurseOctreeToMapOperator.h"
 #include "LogHandler.h"
-#include "RemapIDOperator.h"
 
 static const quint64 DELETED_ENTITIES_EXTRA_USECS_TO_CONSIDER = USECS_PER_MSEC * 50;
 
@@ -1317,42 +1316,59 @@ QVector<EntityItemID> EntityTree::sendEntities(EntityEditPacketSender* packetSen
                                                float x, float y, float z) {
     SendEntitiesOperationArgs args;
     args.packetSender = packetSender;
-    args.localTree = localTree;
+    args.ourTree = this;
+    args.otherTree = localTree;
     args.root = glm::vec3(x, y, z);
-    QVector<EntityItemID> newEntityIDs;
-    args.newEntityIDs = &newEntityIDs;
+    // If this is called repeatedly (e.g., multiple pastes with the same data), the new elements will clash unless we use new identifiers.
+    // We need to keep a map so that we can map parent identifiers correctly.
+    QHash<EntityItemID, EntityItemID> map;
+    args.map = &map;
     recurseTreeWithOperation(sendEntitiesOperation, &args);
     packetSender->releaseQueuedMessages();
 
-    return newEntityIDs;
+    return map.values().toVector();
 }
 
 bool EntityTree::sendEntitiesOperation(OctreeElementPointer element, void* extraData) {
     SendEntitiesOperationArgs* args = static_cast<SendEntitiesOperationArgs*>(extraData);
     EntityTreeElementPointer entityTreeElement = std::static_pointer_cast<EntityTreeElement>(element);
-    entityTreeElement->forEachEntity([&](EntityItemPointer entityItem) {
-        EntityItemID newID(QUuid::createUuid());
-        args->newEntityIDs->append(newID);
-        EntityItemProperties properties = entityItem->getProperties();
-        properties.setPosition(properties.getPosition() + args->root);
+    std::function<const EntityItemID(EntityItemPointer&)> getMapped = [&](EntityItemPointer& item) -> const EntityItemID {
+        EntityItemID oldID = item->getEntityItemID();
+        if (args->map->contains(oldID)) { // Already been handled (e.g., as a parent of somebody that we've processed).
+            return args->map->value(oldID);
+        }
+        EntityItemID newID = QUuid::createUuid();
+        EntityItemProperties properties = item->getProperties();
+        EntityItemID oldParentID = properties.getParentID();
+        if (oldParentID.isInvalidID()) {  // no parent
+            properties.setPosition(properties.getPosition() + args->root);
+        } else {
+            EntityItemPointer parentEntity = args->ourTree->findEntityByEntityItemID(oldParentID);
+            if (parentEntity) { // map the parent
+                // Warning: (non-tail) recursion of getMapped could blow the call stack if the parent hierarchy is VERY deep.
+                properties.setParentID(getMapped(parentEntity));
+                // But do not add root offset in this case.
+            } else { // Should not happen, but let's try to be helpful...
+                item->globalizeProperties(properties, "Cannot find %3 parent of %2 %1", args->root);
+            }
+        }
         properties.markAllChanged(); // so the entire property set is considered new, since we're making a new entity
 
         // queue the packet to send to the server
         args->packetSender->queueEditEntityMessage(PacketType::EntityAdd, newID, properties);
 
         // also update the local tree instantly (note: this is not our tree, but an alternate tree)
-        if (args->localTree) {
-            args->localTree->withWriteLock([&] {
-                args->localTree->addEntity(newID, properties);
+        if (args->otherTree) {
+            args->otherTree->withWriteLock([&] {
+                args->otherTree->addEntity(newID, properties);
             });
         }
-    });
-    return true;
-}
+        args->map->insert(oldID, newID);
+        return newID;
+    };
 
-void EntityTree::remapIDs() {
-    RemapIDOperator theOperator;
-    recurseTreeWithOperator(&theOperator);
+    entityTreeElement->forEachEntity(getMapped);
+    return true;
 }
 
 bool EntityTree::writeToMap(QVariantMap& entityDescription, OctreeElementPointer element, bool skipDefaultValues,
@@ -1393,7 +1409,6 @@ bool EntityTree::readFromMap(QVariantMap& map) {
             qCDebug(entities) << "adding Entity failed:" << entityItemID << properties.getType();
         }
     }
-
     return true;
 }
 
diff --git a/libraries/entities/src/EntityTree.h b/libraries/entities/src/EntityTree.h
index 0b85c5f32f..5c5f5b4eb9 100644
--- a/libraries/entities/src/EntityTree.h
+++ b/libraries/entities/src/EntityTree.h
@@ -16,6 +16,7 @@
 #include <QVector>
 
 #include <Octree.h>
+#include <SpatialParentFinder.h>
 
 class EntityTree;
 typedef std::shared_ptr<EntityTree> EntityTreePointer;
@@ -46,13 +47,14 @@ public:
 class SendEntitiesOperationArgs {
 public:
     glm::vec3 root;
-    EntityTreePointer localTree;
+    EntityTree* ourTree;
+    EntityTreePointer otherTree;
     EntityEditPacketSender* packetSender;
-    QVector<EntityItemID>* newEntityIDs;
+    QHash<EntityItemID, EntityItemID>* map;
 };
 
 
-class EntityTree : public Octree {
+class EntityTree : public Octree, public SpatialParentTree {
     Q_OBJECT
 public:
     EntityTree(bool shouldReaverage = false);
@@ -125,6 +127,7 @@ public:
     EntityItemPointer findClosestEntity(glm::vec3 position, float targetRadius);
     EntityItemPointer findEntityByID(const QUuid& id);
     EntityItemPointer findEntityByEntityItemID(const EntityItemID& entityID);
+    virtual SpatiallyNestablePointer findByID(const QUuid& id) { return findEntityByID(id); }
 
     EntityItemID assignEntityID(const EntityItemID& entityItemID); /// Assigns a known ID for a creator token ID
 
@@ -200,8 +203,6 @@ public:
     bool wantTerseEditLogging() const { return _wantTerseEditLogging; }
     void setWantTerseEditLogging(bool value) { _wantTerseEditLogging = value; }
 
-    void remapIDs();
-
     virtual bool writeToMap(QVariantMap& entityDescription, OctreeElementPointer element, bool skipDefaultValues,
                             bool skipThoseWithBadParents) override;
     virtual bool readFromMap(QVariantMap& entityDescription) override;
diff --git a/libraries/entities/src/ParticleEffectEntityItem.cpp b/libraries/entities/src/ParticleEffectEntityItem.cpp
index 4b798cbcd9..02a86ab952 100644
--- a/libraries/entities/src/ParticleEffectEntityItem.cpp
+++ b/libraries/entities/src/ParticleEffectEntityItem.cpp
@@ -561,6 +561,12 @@ bool ParticleEffectEntityItem::needsToCallUpdate() const {
 
 void ParticleEffectEntityItem::update(const quint64& now) {
 
+    // we check for 'now' in the past in case users set their clock backward
+    if (now < _lastSimulated) {
+        _lastSimulated = now;
+        return;
+    }
+
     float deltaTime = (float)(now - _lastSimulated) / (float)USECS_PER_SECOND;
     _lastSimulated = now;
 
diff --git a/libraries/entities/src/RemapIDOperator.cpp b/libraries/entities/src/RemapIDOperator.cpp
deleted file mode 100644
index eee6e49a1c..0000000000
--- a/libraries/entities/src/RemapIDOperator.cpp
+++ /dev/null
@@ -1,33 +0,0 @@
-//
-//  RemapIDOperator.cpp
-//  libraries/entities/src
-//
-//  Created by Seth Alves on 2015-12-6.
-//  Copyright 2015 High Fidelity, Inc.
-//
-//  Distributed under the Apache License, Version 2.0.
-//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
-//
-
-
-#include "EntityTree.h"
-#include "RemapIDOperator.h"
-
-QUuid RemapIDOperator::remap(const QUuid& oldID) {
-    if (oldID.isNull()) {
-        return oldID;
-    }
-    if (!_oldToNew.contains(oldID)) {
-        _oldToNew[oldID] = QUuid::createUuid();
-    }
-    return _oldToNew[oldID];
-}
-
-bool RemapIDOperator::postRecursion(OctreeElementPointer element) {
-    EntityTreeElementPointer entityTreeElement = std::static_pointer_cast<EntityTreeElement>(element);
-    entityTreeElement->forEachEntity([&](EntityItemPointer entityItem) {
-        entityItem->setID(remap(entityItem->getID()));
-        entityItem->setParentID(remap(entityItem->getParentID()));
-    });
-    return true;
-}
diff --git a/libraries/entities/src/RemapIDOperator.h b/libraries/entities/src/RemapIDOperator.h
deleted file mode 100644
index 439aec28fc..0000000000
--- a/libraries/entities/src/RemapIDOperator.h
+++ /dev/null
@@ -1,30 +0,0 @@
-//
-//  RemapIDOperator.h
-//  libraries/entities/src
-//
-//  Created by Seth Alves on 2015-12-6.
-//  Copyright 2015 High Fidelity, Inc.
-//
-//  Distributed under the Apache License, Version 2.0.
-//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
-//
-
-#ifndef hifi_RemapIDOperator_h
-#define hifi_RemapIDOperator_h
-
-#include "Octree.h"
-
-// this will change all the IDs in an EntityTree.  Parent/Child relationships are maintained.
-
-class RemapIDOperator : public RecurseOctreeOperator {
-public:
-    RemapIDOperator() : RecurseOctreeOperator() {}
-    ~RemapIDOperator() {}
-    virtual bool preRecursion(OctreeElementPointer element) { return true; }
-    virtual bool postRecursion(OctreeElementPointer element);
-private:
-    QUuid remap(const QUuid& oldID);
-    QHash<QUuid, QUuid> _oldToNew;
-};
-
-#endif // hifi_RemapIDOperator_h
diff --git a/libraries/gl/src/gl/OffscreenQmlSurface.cpp b/libraries/gl/src/gl/OffscreenQmlSurface.cpp
index 818b3c6ca8..1d9e6d0149 100644
--- a/libraries/gl/src/gl/OffscreenQmlSurface.cpp
+++ b/libraries/gl/src/gl/OffscreenQmlSurface.cpp
@@ -70,7 +70,7 @@ public:
     virtual bool event(QEvent *e) override;
 
 protected:
-    class Queue : public QQueue<QEvent*> {
+    class Queue : private QQueue<QEvent*> {
     public:
         void add(QEvent::Type type);
         QEvent* take();
@@ -134,12 +134,14 @@ QEvent* OffscreenQmlRenderThread::Queue::take() {
 }
 
 OffscreenQmlRenderThread::OffscreenQmlRenderThread(OffscreenQmlSurface* surface, QOpenGLContext* shareContext) : _surface(surface) {
+    qDebug() << "Building QML Renderer: creating context";
     if (!_canvas.create(shareContext)) {
         static const char* error = "Failed to create OffscreenGLCanvas";
         qWarning() << error;
         throw error;
     };
 
+    qDebug() << "Building QML Renderer: creating render control";
     _renderControl = new QMyQuickRenderControl();
     QQuickWindow::setDefaultAlphaBuffer(true);
     // Create a QQuickWindow that is associated with our render control.
@@ -147,19 +149,25 @@ OffscreenQmlRenderThread::OffscreenQmlRenderThread(OffscreenQmlSurface* surface,
     // NOTE: Must be created on the main thread so that OffscreenQmlSurface can send it events
     // NOTE: Must be created on the rendering thread or it will refuse to render,
     //       so we wait until after its ctor to move object/context to this thread.
+    qDebug() << "Building QML Renderer: creating window";
     _quickWindow = new QQuickWindow(_renderControl);
     _quickWindow->setColor(QColor(255, 255, 255, 0));
     _quickWindow->setFlags(_quickWindow->flags() | static_cast<Qt::WindowFlags>(Qt::WA_TranslucentBackground));
 
     // We can prepare, but we must wait to start() the thread until after the ctor
+    qDebug() << "Building QML Renderer: moving to own thread";
     _renderControl->prepareThread(this);
     _canvas.getContextObject()->moveToThread(this);
     moveToThread(this);
 
+    qDebug() << "Building QML Renderer: complete";
+
     _queue.add(INIT);
 }
 
 void OffscreenQmlRenderThread::run() {
+    qDebug() << "Starting QML Renderer thread";
+
     while (!_quit) {
         QEvent* e = _queue.take();
         event(e);
@@ -208,12 +216,14 @@ void OffscreenQmlRenderThread::setupFbo() {
 }
 
 void OffscreenQmlRenderThread::init() {
+    qDebug() << "Initializing QML Renderer";
+
     connect(_renderControl, &QQuickRenderControl::renderRequested, _surface, &OffscreenQmlSurface::requestRender);
     connect(_renderControl, &QQuickRenderControl::sceneChanged, _surface, &OffscreenQmlSurface::requestUpdate);
 
     if (!_canvas.makeCurrent()) {
-        // Failed to make GL context current, this OffscreenQmlSurface is basically dead
         qWarning("Failed to make context current on QML Renderer Thread");
+        _quit = true;
         return;
     }
 
@@ -360,6 +370,8 @@ void OffscreenQmlSurface::onAboutToQuit() {
 }
 
 void OffscreenQmlSurface::create(QOpenGLContext* shareContext) {
+    qDebug() << "Building QML surface";
+
     _renderer = new OffscreenQmlRenderThread(this, shareContext);
     _renderer->moveToThread(_renderer);
     _renderer->setObjectName("QML Renderer Thread");
diff --git a/libraries/gpu/src/gpu/GLBackend.h b/libraries/gpu/src/gpu/GLBackend.h
index d4efe7fe99..f5abacd279 100644
--- a/libraries/gpu/src/gpu/GLBackend.h
+++ b/libraries/gpu/src/gpu/GLBackend.h
@@ -158,7 +158,6 @@ public:
         ~GLState();
 
         // The state commands to reset to default,
-        // WARNING depending on the order of the State::Field enum
         static const Commands _resetStateCommands;
 
         friend class GLBackend;
diff --git a/libraries/gpu/src/gpu/GLBackendState.cpp b/libraries/gpu/src/gpu/GLBackendState.cpp
index 64bd87c876..36ce1dd555 100644
--- a/libraries/gpu/src/gpu/GLBackendState.cpp
+++ b/libraries/gpu/src/gpu/GLBackendState.cpp
@@ -35,6 +35,7 @@ const GLBackend::GLState::Commands makeResetStateCommands();
 const GLBackend::GLState::Commands GLBackend::GLState::_resetStateCommands = makeResetStateCommands();
 
 
+// NOTE: This must stay in sync with the ordering of the State::Field enum
 const GLBackend::GLState::Commands makeResetStateCommands() {
     // Since State::DEFAULT is a static defined in another .cpp the initialisation order is random
     // and we have a 50/50 chance that State::DEFAULT is not yet initialized.
@@ -69,9 +70,9 @@ const GLBackend::GLState::Commands makeResetStateCommands() {
         CommandPointer(stencilCommand),
         CommandPointer(stencilCommand),
         
-        std::make_shared<Command1B>(&GLBackend::do_setStateAlphaToCoverageEnable, DEFAULT.alphaToCoverageEnable),
-        
         std::make_shared<Command1U>(&GLBackend::do_setStateSampleMask, DEFAULT.sampleMask),
+
+        std::make_shared<Command1B>(&GLBackend::do_setStateAlphaToCoverageEnable, DEFAULT.alphaToCoverageEnable),
         
         std::make_shared<CommandBlend>(&GLBackend::do_setStateBlend, DEFAULT.blendFunction),
         
diff --git a/libraries/gpu/src/gpu/State.h b/libraries/gpu/src/gpu/State.h
index 7e32a7280a..385edec277 100755
--- a/libraries/gpu/src/gpu/State.h
+++ b/libraries/gpu/src/gpu/State.h
@@ -345,6 +345,7 @@ public:
     uint8 getColorWriteMask() const { return _values.colorWriteMask; }
 
     // All the possible fields
+    // NOTE: If you change this, you must update GLBackend::GLState::_resetStateCommands
     enum Field {
         FILL_MODE,
         CULL_MODE,
@@ -364,6 +365,7 @@ public:
         STENCIL_TEST_BACK,
 
         SAMPLE_MASK,
+
         ALPHA_TO_COVERAGE_ENABLE,
 
         BLEND_FUNCTION,
diff --git a/libraries/model/src/model/Geometry.cpp b/libraries/model/src/model/Geometry.cpp
index df86ba2a8f..2bb6cfa436 100755
--- a/libraries/model/src/model/Geometry.cpp
+++ b/libraries/model/src/model/Geometry.cpp
@@ -111,7 +111,7 @@ Box Mesh::evalPartBound(int partNum) const {
     return box;
 }
 
-Box Mesh::evalPartBounds(int partStart, int partEnd, Boxes& bounds) const {
+Box Mesh::evalPartsBound(int partStart, int partEnd) const {
     Box totalBound;
     auto part = _partBuffer.cbegin<Part>() + partStart;
     auto partItEnd = _partBuffer.cbegin<Part>() + partEnd;
diff --git a/libraries/model/src/model/Geometry.h b/libraries/model/src/model/Geometry.h
index f9d9b0eeb4..a3e95c68c0 100755
--- a/libraries/model/src/model/Geometry.h
+++ b/libraries/model/src/model/Geometry.h
@@ -108,9 +108,9 @@ public:
 
     // evaluate the bounding box of A part
     Box evalPartBound(int partNum) const;
-    // evaluate the bounding boxes of the parts in the range [start, end[ and fill the bounds parameter
-    // the returned box is the bounding box of ALL the evaluated part bounds.
-    Box evalPartBounds(int partStart, int partEnd, Boxes& bounds) const;
+    // evaluate the bounding boxes of the parts in the range [start, end]
+    // the returned box is the bounding box of ALL the evaluated parts bound.
+    Box evalPartsBound(int partStart, int partEnd) const;
 
     static gpu::Primitive topologyToPrimitive(Topology topo) { return static_cast<gpu::Primitive>(topo); }
 
diff --git a/libraries/networking/src/AssetClient.cpp b/libraries/networking/src/AssetClient.cpp
index 8cb1f31090..446009ac23 100644
--- a/libraries/networking/src/AssetClient.cpp
+++ b/libraries/networking/src/AssetClient.cpp
@@ -228,7 +228,8 @@ bool AssetClient::getAsset(const QString& hash, DataOffset start, DataOffset end
 
         nodeList->sendPacket(std::move(packet), *assetServer);
 
-        _pendingRequests[assetServer][messageID] = { callback, progressCallback };
+        _pendingRequests[assetServer][messageID] = { QSharedPointer<ReceivedMessage>(), callback, progressCallback };
+
 
         return true;
     } else {
@@ -326,6 +327,9 @@ void AssetClient::handleAssetGetReply(QSharedPointer<ReceivedMessage> message, S
         if (requestIt != messageCallbackMap.end()) {
             auto& callbacks = requestIt->second;
 
+            // Store message in case we need to disconnect from it later.
+            callbacks.message = message;
+
             if (message->isComplete()) {
                 callbacks.completeCallback(true, error, message->readAll());
             } else {
@@ -550,6 +554,12 @@ void AssetClient::handleNodeKilled(SharedNodePointer node) {
         auto messageMapIt = _pendingRequests.find(node);
         if (messageMapIt != _pendingRequests.end()) {
             for (const auto& value : messageMapIt->second) {
+                auto& message = value.second.message;
+                if (message) {
+                    // Disconnect from all signals emitting from the pending message
+                    disconnect(message.data(), nullptr, this, nullptr);
+                }
+
                 value.second.completeCallback(false, AssetServerError::NoError, QByteArray());
             }
             messageMapIt->second.clear();
diff --git a/libraries/networking/src/AssetClient.h b/libraries/networking/src/AssetClient.h
index e46c8c6524..f1890377dc 100644
--- a/libraries/networking/src/AssetClient.h
+++ b/libraries/networking/src/AssetClient.h
@@ -86,14 +86,15 @@ private:
                   ReceivedAssetCallback callback, ProgressCallback progressCallback);
     bool uploadAsset(const QByteArray& data, UploadResultCallback callback);
 
-    struct GetAssetCallbacks {
+    struct GetAssetRequestData {
+        QSharedPointer<ReceivedMessage> message;
         ReceivedAssetCallback completeCallback;
         ProgressCallback progressCallback;
     };
 
     static MessageID _currentID;
     std::unordered_map<SharedNodePointer, std::unordered_map<MessageID, MappingOperationCallback>> _pendingMappingRequests;
-    std::unordered_map<SharedNodePointer, std::unordered_map<MessageID, GetAssetCallbacks>> _pendingRequests;
+    std::unordered_map<SharedNodePointer, std::unordered_map<MessageID, GetAssetRequestData>> _pendingRequests;
     std::unordered_map<SharedNodePointer, std::unordered_map<MessageID, GetInfoCallback>> _pendingInfoRequests;
     std::unordered_map<SharedNodePointer, std::unordered_map<MessageID, UploadResultCallback>> _pendingUploads;
 
diff --git a/libraries/render-utils/src/AbstractViewStateInterface.h b/libraries/render-utils/src/AbstractViewStateInterface.h
index 815cb45423..7c7c263562 100644
--- a/libraries/render-utils/src/AbstractViewStateInterface.h
+++ b/libraries/render-utils/src/AbstractViewStateInterface.h
@@ -46,6 +46,8 @@ public:
     virtual render::ScenePointer getMain3DScene() = 0;
     virtual render::EnginePointer getRenderEngine() = 0;
 
+    virtual void pushPreRenderLambda(void* key, std::function<void()> func) = 0;
+
     // FIXME - we shouldn't assume that there's a single instance of an AbstractViewStateInterface
     static AbstractViewStateInterface* instance();
     static void setInstance(AbstractViewStateInterface* instance);
diff --git a/libraries/render-utils/src/MeshPartPayload.cpp b/libraries/render-utils/src/MeshPartPayload.cpp
index 854630abf0..d295b07caf 100644
--- a/libraries/render-utils/src/MeshPartPayload.cpp
+++ b/libraries/render-utils/src/MeshPartPayload.cpp
@@ -58,7 +58,6 @@ void MeshPartPayload::updateMeshPart(const std::shared_ptr<const model::Mesh>& d
         auto vertexFormat = _drawMesh->getVertexFormat();
         _hasColorAttrib = vertexFormat->hasAttribute(gpu::Stream::COLOR);
         _drawPart = _drawMesh->getPartBuffer().get<model::Mesh::Part>(partIndex);
-
         _localBound = _drawMesh->evalPartBound(partIndex);
     }
 }
@@ -352,7 +351,23 @@ void ModelMeshPartPayload::initCache() {
 
 
 void ModelMeshPartPayload::notifyLocationChanged() {
-    _model->_needsUpdateClusterMatrices = true;
+
+}
+
+void ModelMeshPartPayload::updateTransformForSkinnedMesh(const Transform& transform, const Transform& offsetTransform, const QVector<glm::mat4>& clusterMatrices) {
+    ModelMeshPartPayload::updateTransform(transform, offsetTransform);
+
+    if (clusterMatrices.size() > 0) {
+        _worldBound = AABox();
+        for (auto& clusterMatrix : clusterMatrices) {
+            AABox clusterBound = _localBound;
+            clusterBound.transform(clusterMatrix);
+            _worldBound += clusterBound;
+        }
+
+        // clusterMatrix has world rotation but not world translation.
+        _worldBound.translate(transform.getTranslation());
+    }
 }
 
 ItemKey ModelMeshPartPayload::getKey() const {
@@ -377,12 +392,6 @@ ItemKey ModelMeshPartPayload::getKey() const {
     return builder.build();
 }
 
-Item::Bound ModelMeshPartPayload::getBound() const {
-    // NOTE: we can't cache this bounds because we need to handle the case of a moving
-    // entity or mesh part.
-    return _model->getPartBounds(_meshIndex, _partIndex, _transform.getTranslation(), _transform.getRotation());
-}
-
 ShapeKey ModelMeshPartPayload::getShapeKey() const {
     assert(_model->isLoaded());
     const FBXGeometry& geometry = _model->getFBXGeometry();
diff --git a/libraries/render-utils/src/MeshPartPayload.h b/libraries/render-utils/src/MeshPartPayload.h
index 9f73a46a93..41869ec7e3 100644
--- a/libraries/render-utils/src/MeshPartPayload.h
+++ b/libraries/render-utils/src/MeshPartPayload.h
@@ -74,15 +74,15 @@ namespace render {
 class ModelMeshPartPayload : public MeshPartPayload {
 public:
     ModelMeshPartPayload(Model* model, int meshIndex, int partIndex, int shapeIndex, const Transform& transform, const Transform& offsetTransform);
-    
+
     typedef render::Payload<ModelMeshPartPayload> Payload;
     typedef Payload::DataPointer Pointer;
 
     void notifyLocationChanged() override;
+    void updateTransformForSkinnedMesh(const Transform& transform, const Transform& offsetTransform, const QVector<glm::mat4>& clusterMatrices);
 
     // Render Item interface
     render::ItemKey getKey() const override;
-    render::Item::Bound getBound() const override;
     render::ShapeKey getShapeKey() const override; // shape interface
     void render(RenderArgs* args) const override;
 
@@ -101,4 +101,11 @@ public:
     bool _isBlendShaped{ false };
 };
 
+namespace render {
+    template <> const ItemKey payloadGetKey(const ModelMeshPartPayload::Pointer& payload);
+    template <> const Item::Bound payloadGetBound(const ModelMeshPartPayload::Pointer& payload);
+    template <> const ShapeKey shapeGetShapeKey(const ModelMeshPartPayload::Pointer& payload);
+    template <> void payloadRender(const ModelMeshPartPayload::Pointer& payload, RenderArgs* args);
+}
+
 #endif // hifi_MeshPartPayload_h
diff --git a/libraries/render-utils/src/Model.cpp b/libraries/render-utils/src/Model.cpp
index 545d239549..8d59d5f736 100644
--- a/libraries/render-utils/src/Model.cpp
+++ b/libraries/render-utils/src/Model.cpp
@@ -130,25 +130,60 @@ void Model::setOffset(const glm::vec3& offset) {
 }
 
 void Model::enqueueLocationChange() {
-    render::ScenePointer scene = AbstractViewStateInterface::instance()->getMain3DScene();
 
-    Transform transform;
-    transform.setTranslation(_translation);
-    transform.setRotation(_rotation);
+    // queue up this work for later processing, at the end of update and just before rendering.
+    // the application will ensure only the last lambda is actually invoked.
+    void* key = (void*)this;
+    std::weak_ptr<Model> weakSelf = shared_from_this();
+    AbstractViewStateInterface::instance()->pushPreRenderLambda(key, [weakSelf]() {
 
-    Transform offset;
-    offset.setScale(_scale);
-    offset.postTranslate(_offset);
+        // do nothing, if the model has already been destroyed.
+        auto self = weakSelf.lock();
+        if (!self) {
+            return;
+        }
 
-    render::PendingChanges pendingChanges;
-    foreach (auto itemID, _renderItems.keys()) {
-        pendingChanges.updateItem<MeshPartPayload>(itemID, [transform, offset](MeshPartPayload& data) {
-            data.updateTransform(transform, offset);
-            data.notifyLocationChanged();
-        });
-    }
+        render::ScenePointer scene = AbstractViewStateInterface::instance()->getMain3DScene();
 
-    scene->enqueuePendingChanges(pendingChanges);
+        Transform modelTransform;
+        modelTransform.setScale(self->_scale);
+        modelTransform.setTranslation(self->_translation);
+        modelTransform.setRotation(self->_rotation);
+
+        Transform modelMeshOffset;
+        if (self->isLoaded()) {
+            // includes model offset and unitScale.
+            modelMeshOffset = Transform(self->_rig->getGeometryToRigTransform());
+        } else {
+            modelMeshOffset.postTranslate(self->_offset);
+        }
+
+        // only apply offset only, collision mesh does not share the same unit scale as the FBX file's mesh.
+        Transform collisionMeshOffset;
+        collisionMeshOffset.postTranslate(self->_offset);
+
+        render::PendingChanges pendingChanges;
+        foreach (auto itemID, self->_modelMeshRenderItems.keys()) {
+            pendingChanges.updateItem<ModelMeshPartPayload>(itemID, [modelTransform, modelMeshOffset](ModelMeshPartPayload& data) {
+
+                // lazy update of cluster matrices used for rendering.  We need to update them here, so we can correctly update the bounding box.
+                data._model->updateClusterMatrices(modelTransform.getTranslation(), modelTransform.getRotation());
+
+                // update the model transform and bounding box for this render item.
+                const Model::MeshState& state = data._model->_meshStates.at(data._meshIndex);
+                data.updateTransformForSkinnedMesh(modelTransform, modelMeshOffset, state.clusterMatrices);
+            });
+        }
+
+        foreach (auto itemID, self->_collisionRenderItems.keys()) {
+            pendingChanges.updateItem<MeshPartPayload>(itemID, [modelTransform, collisionMeshOffset](MeshPartPayload& data) {
+                // update the model transform for this render item.
+                data.updateTransform(modelTransform, collisionMeshOffset);
+            });
+        }
+
+        scene->enqueuePendingChanges(pendingChanges);
+    });
 }
 
 void Model::initJointTransforms() {
@@ -497,8 +532,11 @@ void Model::setVisibleInScene(bool newValue, std::shared_ptr<render::Scene> scen
         _isVisible = newValue;
 
         render::PendingChanges pendingChanges;
-        foreach (auto item, _renderItems.keys()) {
-            pendingChanges.resetItem(item, _renderItems[item]);
+        foreach (auto item, _modelMeshRenderItems.keys()) {
+            pendingChanges.resetItem(item, _modelMeshRenderItems[item]);
+        }
+        foreach (auto item, _collisionRenderItems.keys()) {
+            pendingChanges.resetItem(item, _modelMeshRenderItems[item]);
         }
         scene->enqueuePendingChanges(pendingChanges);
     }
@@ -514,14 +552,25 @@ bool Model::addToScene(std::shared_ptr<render::Scene> scene, render::PendingChan
 
     bool somethingAdded = false;
 
-    foreach (auto renderItem, _renderItemsSet) {
+    foreach (auto renderItem, _modelMeshRenderItemsSet) {
+        auto item = scene->allocateID();
+        auto renderPayload = std::make_shared<ModelMeshPartPayload::Payload>(renderItem);
+        pendingChanges.resetItem(item, renderPayload);
+        pendingChanges.updateItem<ModelMeshPartPayload>(item, [](ModelMeshPartPayload& data) {
+            data.notifyLocationChanged();
+        });
+        _modelMeshRenderItems.insert(item, renderPayload);
+        somethingAdded = true;
+    }
+
+    foreach (auto renderItem, _collisionRenderItemsSet) {
         auto item = scene->allocateID();
         auto renderPayload = std::make_shared<MeshPartPayload::Payload>(renderItem);
         pendingChanges.resetItem(item, renderPayload);
         pendingChanges.updateItem<MeshPartPayload>(item, [](MeshPartPayload& data) {
             data.notifyLocationChanged();
         });
-        _renderItems.insert(item, renderPayload);
+        _collisionRenderItems.insert(item, renderPayload);
         somethingAdded = true;
     }
 
@@ -541,7 +590,19 @@ bool Model::addToScene(std::shared_ptr<render::Scene> scene,
 
     bool somethingAdded = false;
 
-    foreach (auto renderItem, _renderItemsSet) {
+    foreach (auto renderItem, _modelMeshRenderItemsSet) {
+        auto item = scene->allocateID();
+        auto renderPayload = std::make_shared<ModelMeshPartPayload::Payload>(renderItem);
+        renderPayload->addStatusGetters(statusGetters);
+        pendingChanges.resetItem(item, renderPayload);
+        pendingChanges.updateItem<ModelMeshPartPayload>(item, [](ModelMeshPartPayload& data) {
+            data.notifyLocationChanged();
+        });
+        _modelMeshRenderItems.insert(item, renderPayload);
+        somethingAdded = true;
+    }
+
+    foreach (auto renderItem, _collisionRenderItemsSet) {
         auto item = scene->allocateID();
         auto renderPayload = std::make_shared<MeshPartPayload::Payload>(renderItem);
         renderPayload->addStatusGetters(statusGetters);
@@ -549,7 +610,7 @@ bool Model::addToScene(std::shared_ptr<render::Scene> scene,
         pendingChanges.updateItem<MeshPartPayload>(item, [](MeshPartPayload& data) {
             data.notifyLocationChanged();
         });
-        _renderItems.insert(item, renderPayload);
+        _collisionRenderItems.insert(item, renderPayload);
         somethingAdded = true;
     }
 
@@ -559,11 +620,16 @@ bool Model::addToScene(std::shared_ptr<render::Scene> scene,
 }
 
 void Model::removeFromScene(std::shared_ptr<render::Scene> scene, render::PendingChanges& pendingChanges) {
-    foreach (auto item, _renderItems.keys()) {
+    foreach (auto item, _modelMeshRenderItems.keys()) {
         pendingChanges.removeItem(item);
     }
-    _renderItems.clear();
-    _renderItemsSet.clear();
+    _modelMeshRenderItems.clear();
+    _modelMeshRenderItemsSet.clear();
+    foreach (auto item, _collisionRenderItems.keys()) {
+        pendingChanges.removeItem(item);
+    }
+    _collisionRenderItems.clear();
+    _collisionRenderItemsSet.clear();
     _meshGroupsKnown = false;
     _readyWhenAdded = false;
 }
@@ -1175,10 +1241,14 @@ void Model::segregateMeshGroups() {
         return;
     }
 
-    Q_ASSERT(_renderItems.isEmpty()); // We should not have any existing renderItems if we enter this section of code
-    Q_ASSERT(_renderItemsSet.isEmpty()); // We should not have any existing renderItemsSet if we enter this section of code
+    // We should not have any existing renderItems if we enter this section of code
+    Q_ASSERT(_modelMeshRenderItems.isEmpty());
+    Q_ASSERT(_modelMeshRenderItemsSet.isEmpty());
+    Q_ASSERT(_collisionRenderItems.isEmpty());
+    Q_ASSERT(_collisionRenderItemsSet.isEmpty());
 
-    _renderItemsSet.clear();
+    _modelMeshRenderItemsSet.clear();
+    _collisionRenderItemsSet.clear();
 
     Transform transform;
     transform.setTranslation(_translation);
@@ -1204,9 +1274,9 @@ void Model::segregateMeshGroups() {
                     _collisionHullMaterial->setMetallic(0.02f);
                     _collisionHullMaterial->setRoughness(0.5f);
                 }
-                _renderItemsSet << std::make_shared<MeshPartPayload>(networkMesh, partIndex, _collisionHullMaterial, transform, offset);
+                _collisionRenderItemsSet << std::make_shared<MeshPartPayload>(networkMesh, partIndex, _collisionHullMaterial, transform, offset);
             } else {
-                _renderItemsSet << std::make_shared<ModelMeshPartPayload>(this, i, partIndex, shapeID, transform, offset);
+                _modelMeshRenderItemsSet << std::make_shared<ModelMeshPartPayload>(this, i, partIndex, shapeID, transform, offset);
             }
 
             shapeID++;
@@ -1229,13 +1299,21 @@ bool Model::initWhenReady(render::ScenePointer scene) {
         offset.setScale(_scale);
         offset.postTranslate(_offset);
 
-        foreach (auto renderItem, _renderItemsSet) {
+        foreach (auto renderItem, _modelMeshRenderItemsSet) {
+            auto item = scene->allocateID();
+            auto renderPayload = std::make_shared<ModelMeshPartPayload::Payload>(renderItem);
+            _modelMeshRenderItems.insert(item, renderPayload);
+            pendingChanges.resetItem(item, renderPayload);
+            pendingChanges.updateItem<ModelMeshPartPayload>(item, [transform, offset](MeshPartPayload& data) {
+                data.notifyLocationChanged();
+            });
+        }
+        foreach (auto renderItem, _collisionRenderItemsSet) {
             auto item = scene->allocateID();
             auto renderPayload = std::make_shared<MeshPartPayload::Payload>(renderItem);
-            _renderItems.insert(item, renderPayload);
+            _collisionRenderItems.insert(item, renderPayload);
             pendingChanges.resetItem(item, renderPayload);
-            pendingChanges.updateItem<MeshPartPayload>(item, [transform,offset](MeshPartPayload& data) {
-                data.updateTransform(transform, offset);
+            pendingChanges.updateItem<MeshPartPayload>(item, [transform, offset](MeshPartPayload& data) {
                 data.notifyLocationChanged();
             });
         }
diff --git a/libraries/render-utils/src/Model.h b/libraries/render-utils/src/Model.h
index 744a4ce605..e4a8fa3b36 100644
--- a/libraries/render-utils/src/Model.h
+++ b/libraries/render-utils/src/Model.h
@@ -44,6 +44,7 @@ namespace render {
     typedef unsigned int ItemID;
 }
 class MeshPartPayload;
+class ModelMeshPartPayload;
 class ModelRenderLocations;
 
 inline uint qHash(const std::shared_ptr<MeshPartPayload>& a, uint seed) {
@@ -73,6 +74,7 @@ public:
     }
 
     /// Sets the URL of the model to render.
+    // Should only be called from the model's rendering thread to avoid access violations of changed geometry.
     Q_INVOKABLE void setURL(const QUrl& url);
     const QUrl& getURL() const { return _url; }
 
@@ -133,7 +135,8 @@ public:
     /// Provided as a convenience, will crash if !isCollisionLoaded()
     const FBXGeometry& getCollisionFBXGeometry() const { assert(isCollisionLoaded()); return getCollisionGeometry()->getGeometry()->getGeometry(); }
 
-    // Set the model to use for collisions
+    // Set the model to use for collisions.
+    // Should only be called from the model's rendering thread to avoid access violations of changed geometry.
     Q_INVOKABLE void setCollisionModelURL(const QUrl& url);
     const QUrl& getCollisionURL() const { return _collisionUrl; }
 
@@ -373,8 +376,12 @@ protected:
     bool _renderCollisionHull;
 
 
-    QSet<std::shared_ptr<MeshPartPayload>> _renderItemsSet;
-    QMap<render::ItemID, render::PayloadPointer> _renderItems;
+    QSet<std::shared_ptr<MeshPartPayload>> _collisionRenderItemsSet;
+    QMap<render::ItemID, render::PayloadPointer> _collisionRenderItems;
+
+    QSet<std::shared_ptr<ModelMeshPartPayload>> _modelMeshRenderItemsSet;
+    QMap<render::ItemID, render::PayloadPointer> _modelMeshRenderItems;
+
     bool _readyWhenAdded { false };
     bool _needsReload { true };
     bool _needsUpdateClusterMatrices { true };
diff --git a/libraries/script-engine/src/ScriptEngine.cpp b/libraries/script-engine/src/ScriptEngine.cpp
index 3f403b3677..a6541dc031 100644
--- a/libraries/script-engine/src/ScriptEngine.cpp
+++ b/libraries/script-engine/src/ScriptEngine.cpp
@@ -673,11 +673,14 @@ void ScriptEngine::run() {
         }
 
         qint64 now = usecTimestampNow();
-        float deltaTime = (float) (now - lastUpdate) / (float) USECS_PER_SECOND;
 
-        if (!_isFinished) {
-            if (_wantSignals) {
-                emit update(deltaTime);
+        // we check for 'now' in the past in case people set their clock back
+        if (lastUpdate < now) {
+            float deltaTime = (float) (now - lastUpdate) / (float) USECS_PER_SECOND;
+            if (!_isFinished) {
+                if (_wantSignals) {
+                    emit update(deltaTime);
+                }
             }
         }
         lastUpdate = now;
diff --git a/libraries/shared/src/AABox.cpp b/libraries/shared/src/AABox.cpp
index 0b453e6f36..a3afa220c9 100644
--- a/libraries/shared/src/AABox.cpp
+++ b/libraries/shared/src/AABox.cpp
@@ -17,6 +17,8 @@
 #include "GeometryUtil.h"
 #include "NumericalConstants.h"
 
+const glm::vec3 AABox::INFINITY_VECTOR(std::numeric_limits<float>::infinity());
+
 AABox::AABox(const AACube& other) :
     _corner(other.getCorner()), _scale(other.getScale(), other.getScale(), other.getScale()) {
 }
@@ -34,7 +36,7 @@ AABox::AABox(const glm::vec3& corner, const glm::vec3& dimensions) :
     _corner(corner), _scale(dimensions) {
 };
 
-AABox::AABox() : _corner(std::numeric_limits<float>::infinity()), _scale(0.0f) {
+AABox::AABox() : _corner(INFINITY_VECTOR), _scale(0.0f) {
 };
 
 glm::vec3 AABox::calcCenter() const {
@@ -475,8 +477,15 @@ AABox AABox::clamp(float min, float max) const {
 }
 
 AABox& AABox::operator += (const glm::vec3& point) {
-    _corner = glm::min(_corner, point);
-    _scale = glm::max(_scale, point - _corner);
+
+    if (isInvalid()) {
+        _corner = glm::min(_corner, point);
+    } else {
+        glm::vec3 maximum(_corner + _scale);
+        _corner = glm::min(_corner, point);
+        maximum = glm::max(maximum, point);
+        _scale = maximum - _corner;
+    }
 
     return (*this);
 }
@@ -484,17 +493,31 @@ AABox& AABox::operator += (const glm::vec3& point) {
 AABox& AABox::operator += (const AABox& box) {
     if (!box.isInvalid()) {
         (*this) += box._corner;
-       _scale = glm::max(_scale, box.calcTopFarLeft() - _corner);
+        (*this) += box.calcTopFarLeft();
     }
     return (*this);
 }
 
+void AABox::embiggen(float scale) {
+    _corner += scale * (-0.5f * _scale);
+    _scale *= scale;
+}
+
+void AABox::embiggen(const glm::vec3& scale) {
+    _corner += scale * (-0.5f * _scale);
+    _scale *= scale;
+}
+
+void AABox::scale(float scale) {
+    _corner *= scale;
+    _scale *= scale;
+}
+
 void AABox::scale(const glm::vec3& scale) {
     _corner *= scale;
     _scale *= scale;
 }
 
-
 void AABox::rotate(const glm::quat& rotation) {
     auto minimum = _corner;
     auto maximum = _corner + _scale;
@@ -544,3 +567,47 @@ void AABox::transform(const Transform& transform) {
     rotate(transform.getRotation());
     translate(transform.getTranslation());
 }
+
+void AABox::transform(const glm::mat4& matrix) {
+    auto minimum = _corner;
+    auto maximum = _corner + _scale;
+
+    glm::vec3 bottomLeftNear(minimum.x, minimum.y, minimum.z);
+    glm::vec3 bottomRightNear(maximum.x, minimum.y, minimum.z);
+    glm::vec3 bottomLeftFar(minimum.x, minimum.y, maximum.z);
+    glm::vec3 bottomRightFar(maximum.x, minimum.y, maximum.z);
+    glm::vec3 topLeftNear(minimum.x, maximum.y, minimum.z);
+    glm::vec3 topRightNear(maximum.x, maximum.y, minimum.z);
+    glm::vec3 topLeftFar(minimum.x, maximum.y, maximum.z);
+    glm::vec3 topRightFar(maximum.x, maximum.y, maximum.z);
+
+    glm::vec3 bottomLeftNearTransformed = transformPoint(matrix, bottomLeftNear);
+    glm::vec3 bottomRightNearTransformed = transformPoint(matrix, bottomRightNear);
+    glm::vec3 bottomLeftFarTransformed = transformPoint(matrix, bottomLeftFar);
+    glm::vec3 bottomRightFarTransformed = transformPoint(matrix, bottomRightFar);
+    glm::vec3 topLeftNearTransformed = transformPoint(matrix, topLeftNear);
+    glm::vec3 topRightNearTransformed = transformPoint(matrix, topRightNear);
+    glm::vec3 topLeftFarTransformed = transformPoint(matrix, topLeftFar);
+    glm::vec3 topRightFarTransformed = transformPoint(matrix, topRightFar);
+
+    minimum = glm::min(bottomLeftNearTransformed,
+        glm::min(bottomRightNearTransformed,
+        glm::min(bottomLeftFarTransformed,
+        glm::min(bottomRightFarTransformed,
+        glm::min(topLeftNearTransformed,
+        glm::min(topRightNearTransformed,
+        glm::min(topLeftFarTransformed,
+        topRightFarTransformed)))))));
+
+    maximum = glm::max(bottomLeftNearTransformed,
+        glm::max(bottomRightNearTransformed,
+        glm::max(bottomLeftFarTransformed,
+        glm::max(bottomRightFarTransformed,
+        glm::max(topLeftNearTransformed,
+        glm::max(topRightNearTransformed,
+        glm::max(topLeftFarTransformed,
+        topRightFarTransformed)))))));
+
+    _corner = minimum;
+    _scale = maximum - minimum;
+}
diff --git a/libraries/shared/src/AABox.h b/libraries/shared/src/AABox.h
index ec06c60121..30bde2d717 100644
--- a/libraries/shared/src/AABox.h
+++ b/libraries/shared/src/AABox.h
@@ -58,7 +58,6 @@ public:
     const glm::vec3& getMinimumPoint() const { return _corner; }
     glm::vec3 getMaximumPoint() const { return calcTopFarLeft(); }
 
-
     bool contains(const glm::vec3& point) const;
     bool contains(const AABox& otherBox) const;
     bool touches(const AABox& otherBox) const;
@@ -93,10 +92,19 @@ public:
     void scale(float scale);
     void scale(const glm::vec3& scale);
 
+    /// make the AABox bigger (scale about it's center)
+    void embiggen(float scale);
+    void embiggen(const glm::vec3& scale);
+
     // Transform the extents with transform
     void transform(const Transform& transform);
 
-    bool isInvalid() const { return _corner == glm::vec3(std::numeric_limits<float>::infinity()); }
+    // Transform the extents with matrix
+    void transform(const glm::mat4& matrix);
+
+    static const glm::vec3 INFINITY_VECTOR;
+
+    bool isInvalid() const { return _corner == INFINITY_VECTOR; }
 
 private:
     glm::vec3 getClosestPointOnFace(const glm::vec3& point, BoxFace face) const;
diff --git a/libraries/shared/src/SpatialParentFinder.h b/libraries/shared/src/SpatialParentFinder.h
index 9b49490fa5..aae7d9f040 100644
--- a/libraries/shared/src/SpatialParentFinder.h
+++ b/libraries/shared/src/SpatialParentFinder.h
@@ -19,6 +19,10 @@
 class SpatiallyNestable;
 using SpatiallyNestableWeakPointer = std::weak_ptr<SpatiallyNestable>;
 using SpatiallyNestablePointer = std::shared_ptr<SpatiallyNestable>;
+class SpatialParentTree {
+public:
+    virtual SpatiallyNestablePointer findByID(const QUuid& id) { return nullptr; }
+};
 class SpatialParentFinder : public Dependency {
 
 
@@ -31,7 +35,7 @@ public:
     SpatialParentFinder() { }
     virtual ~SpatialParentFinder() { }
 
-    virtual SpatiallyNestableWeakPointer find(QUuid parentID, bool& success) const = 0;
+    virtual SpatiallyNestableWeakPointer find(QUuid parentID, bool& success, SpatialParentTree* entityTree = nullptr) const = 0;
 };
 
 #endif // hifi_SpatialParentFinder_h
diff --git a/libraries/shared/src/SpatiallyNestable.cpp b/libraries/shared/src/SpatiallyNestable.cpp
index 55da4822ef..13bf5d9054 100644
--- a/libraries/shared/src/SpatiallyNestable.cpp
+++ b/libraries/shared/src/SpatiallyNestable.cpp
@@ -105,7 +105,7 @@ SpatiallyNestablePointer SpatiallyNestable::getParentPointer(bool& success) cons
         success = false;
         return nullptr;
     }
-    _parent = parentFinder->find(parentID, success);
+    _parent = parentFinder->find(parentID, success, getParentTree());
     if (!success) {
         return nullptr;
     }
diff --git a/libraries/shared/src/SpatiallyNestable.h b/libraries/shared/src/SpatiallyNestable.h
index a65c7c7f2c..379f2facd7 100644
--- a/libraries/shared/src/SpatiallyNestable.h
+++ b/libraries/shared/src/SpatiallyNestable.h
@@ -140,6 +140,7 @@ public:
     bool isDead() const { return _isDead; }
 
     bool isParentIDValid() const { bool success = false; getParentPointer(success); return success; }
+    virtual SpatialParentTree* getParentTree() const { return nullptr; }
 
 protected:
     const NestableType _nestableType; // EntityItem or an AvatarData
diff --git a/tests/shared/src/AABoxTests.cpp b/tests/shared/src/AABoxTests.cpp
index fd709a488c..b9ab95bb09 100644
--- a/tests/shared/src/AABoxTests.cpp
+++ b/tests/shared/src/AABoxTests.cpp
@@ -151,3 +151,21 @@ void AABoxTests::testTouchesSphere() {
     }
 }
 
+void AABoxTests::testScale() {
+    AABox box1(glm::vec3(2.0f), glm::vec3(1.0f));
+    QCOMPARE(box1.contains(glm::vec3(0.0f)), false);
+    box1.scale(glm::vec3(10.0f));
+    QCOMPARE(box1.contains(glm::vec3(0.0f)), false);
+    QCOMPARE(box1.contains(glm::vec3(2.0f * 10.0f)), true);
+
+    AABox box2(glm::vec3(2.0f), glm::vec3(1.0f));
+    QCOMPARE(box2.contains(glm::vec3(0.0f)), false);
+    box2.embiggen(glm::vec3(10.0f));
+    QCOMPARE(box2.contains(glm::vec3(0.0f)), true);
+
+    AABox box3;
+    box3 += glm::vec3(0.0f, 0.0f, 0.0f);
+    box3 += glm::vec3(1.0f, 1.0f, 1.0f);
+    box3 += glm::vec3(-1.0f, -1.0f, -1.0f);
+    QCOMPARE(box3.contains(glm::vec3(0.5f, 0.5f, 0.5f)), true);
+}
diff --git a/tests/shared/src/AABoxTests.h b/tests/shared/src/AABoxTests.h
index fe7afede57..c777f8e94f 100644
--- a/tests/shared/src/AABoxTests.h
+++ b/tests/shared/src/AABoxTests.h
@@ -23,6 +23,7 @@ private slots:
     void testCtorsAndSetters();
     void testContainsPoint();
     void testTouchesSphere();
+    void testScale();
 };
 
 #endif // hifi_AABoxTests_h