diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index e4adb38cd4..fb414311ef 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -2373,8 +2373,8 @@ void Application::updateShadowMap() {
     updateUntranslatedViewMatrix();
 
     _avatarManager.renderAvatars(Avatar::SHADOW_RENDER_MODE);
-    _particles.render();
-    _models.render();
+    _particles.render(OctreeRenderer::SHADOW_RENDER_MODE);
+    _models.render(OctreeRenderer::SHADOW_RENDER_MODE);
 
     glPopMatrix();
 
diff --git a/interface/src/Menu.cpp b/interface/src/Menu.cpp
index 0587e979f6..ad2b220d55 100644
--- a/interface/src/Menu.cpp
+++ b/interface/src/Menu.cpp
@@ -292,7 +292,6 @@ Menu::Menu() :
     addCheckableActionToQMenuAndActionHash(renderOptionsMenu, MenuOption::Metavoxels, 0, true);
     addCheckableActionToQMenuAndActionHash(renderOptionsMenu, MenuOption::BuckyBalls, 0, false);
     addCheckableActionToQMenuAndActionHash(renderOptionsMenu, MenuOption::Particles, 0, true);
-    addCheckableActionToQMenuAndActionHash(renderOptionsMenu, MenuOption::Models, 0, true);
     addActionToQMenuAndActionHash(renderOptionsMenu, MenuOption::LodTools, Qt::SHIFT | Qt::Key_L, this, SLOT(lodTools()));
 
     QMenu* voxelOptionsMenu = developerMenu->addMenu("Voxel Options");
@@ -309,6 +308,12 @@ Menu::Menu() :
     addCheckableActionToQMenuAndActionHash(voxelOptionsMenu, MenuOption::DontFadeOnVoxelServerChanges);
     addCheckableActionToQMenuAndActionHash(voxelOptionsMenu, MenuOption::DisableAutoAdjustLOD);
 
+    QMenu* modelOptionsMenu = developerMenu->addMenu("Model Options");
+    addCheckableActionToQMenuAndActionHash(modelOptionsMenu, MenuOption::Models, 0, true);
+    addCheckableActionToQMenuAndActionHash(modelOptionsMenu, MenuOption::DisplayModelBounds, 0, false);
+    addCheckableActionToQMenuAndActionHash(modelOptionsMenu, MenuOption::DisplayModelElementProxy, 0, false);
+    addCheckableActionToQMenuAndActionHash(modelOptionsMenu, MenuOption::DisplayModelElementChildProxies, 0, false);
+
     QMenu* avatarOptionsMenu = developerMenu->addMenu("Avatar Options");
 
     addCheckableActionToQMenuAndActionHash(avatarOptionsMenu, MenuOption::Avatars, 0, true);
diff --git a/interface/src/Menu.h b/interface/src/Menu.h
index d1097929f7..f1d35fcb81 100644
--- a/interface/src/Menu.h
+++ b/interface/src/Menu.h
@@ -304,6 +304,9 @@ namespace MenuOption {
     const QString DisplayFrustum = "Display Frustum";
     const QString DisplayHands = "Display Hands";
     const QString DisplayHandTargets = "Display Hand Targets";
+    const QString DisplayModelBounds = "Display Model Bounds";
+    const QString DisplayModelElementProxy = "Display Model Element Bounds";
+    const QString DisplayModelElementChildProxies = "Display Model Element Children";
     const QString DontFadeOnVoxelServerChanges = "Don't Fade In/Out on Voxel Server Changes";
     const QString EchoLocalAudio = "Echo Local Audio";
     const QString EchoServerAudio = "Echo Server Audio";
@@ -338,6 +341,7 @@ namespace MenuOption {
     const QString Metavoxels = "Metavoxels";
     const QString Mirror = "Mirror";
     const QString Models = "Models";
+    const QString ModelOptions = "Model Options";
     const QString MoveWithLean = "Move with Lean";
     const QString MuteAudio = "Mute Microphone";
     const QString MuteEnvironment = "Mute Environment";
diff --git a/interface/src/avatar/Avatar.cpp b/interface/src/avatar/Avatar.cpp
index a084ee0003..bc2bbb6712 100644
--- a/interface/src/avatar/Avatar.cpp
+++ b/interface/src/avatar/Avatar.cpp
@@ -215,17 +215,20 @@ void Avatar::render(const glm::vec3& cameraPosition, RenderMode renderMode) {
         if (Menu::getInstance()->isOptionChecked(MenuOption::Avatars)) {
             renderBody(renderMode, glowLevel);
         }
-        if (Menu::getInstance()->isOptionChecked(MenuOption::RenderSkeletonCollisionShapes)) {
+        if (renderMode != SHADOW_RENDER_MODE && 
+                Menu::getInstance()->isOptionChecked(MenuOption::RenderSkeletonCollisionShapes)) {
             _skeletonModel.updateShapePositions();
             _skeletonModel.renderJointCollisionShapes(0.7f);
         }
-        if (Menu::getInstance()->isOptionChecked(MenuOption::RenderHeadCollisionShapes)) {
+        if (renderMode != SHADOW_RENDER_MODE && 
+                Menu::getInstance()->isOptionChecked(MenuOption::RenderHeadCollisionShapes)) {
             if (shouldRenderHead(cameraPosition, renderMode)) {
                 getHead()->getFaceModel().updateShapePositions();
                 getHead()->getFaceModel().renderJointCollisionShapes(0.7f);
             }
         }
-        if (Menu::getInstance()->isOptionChecked(MenuOption::RenderBoundingCollisionShapes)) {
+        if (renderMode != SHADOW_RENDER_MODE && 
+                Menu::getInstance()->isOptionChecked(MenuOption::RenderBoundingCollisionShapes)) {
             if (shouldRenderHead(cameraPosition, renderMode)) {
                 getHead()->getFaceModel().updateShapePositions();
                 getHead()->getFaceModel().renderBoundingCollisionShapes(0.7f);
@@ -234,7 +237,7 @@ void Avatar::render(const glm::vec3& cameraPosition, RenderMode renderMode) {
             }
         }
         // If this is the avatar being looked at, render a little ball above their head
-        if (_isLookAtTarget) {
+        if (renderMode != SHADOW_RENDER_MODE &&_isLookAtTarget) {
             const float LOOK_AT_INDICATOR_RADIUS = 0.03f;
             const float LOOK_AT_INDICATOR_HEIGHT = 0.60f;
             const float LOOK_AT_INDICATOR_COLOR[] = { 0.8f, 0.0f, 0.0f, 0.5f };
@@ -340,7 +343,8 @@ glm::quat Avatar::computeRotationFromBodyToWorldUp(float proportion) const {
 
 void Avatar::renderBody(RenderMode renderMode, float glowLevel) {
     Model::RenderMode modelRenderMode = (renderMode == SHADOW_RENDER_MODE) ?
-    Model::SHADOW_RENDER_MODE : Model::DEFAULT_RENDER_MODE;
+                            Model::SHADOW_RENDER_MODE : Model::DEFAULT_RENDER_MODE;
+
     {
         Glower glower(glowLevel);
         
@@ -351,7 +355,7 @@ void Avatar::renderBody(RenderMode renderMode, float glowLevel) {
         }
         _skeletonModel.render(1.0f, modelRenderMode);
         renderAttachments(modelRenderMode);
-        getHand()->render(false);
+        getHand()->render(false, modelRenderMode);
     }
     getHead()->render(1.0f, modelRenderMode);
 }
diff --git a/interface/src/avatar/Hand.cpp b/interface/src/avatar/Hand.cpp
index c925e452b2..320a8477c1 100644
--- a/interface/src/avatar/Hand.cpp
+++ b/interface/src/avatar/Hand.cpp
@@ -192,11 +192,11 @@ void Hand::calculateGeometry() {
     }
 }
 
-void Hand::render(bool isMine) {
-    
+void Hand::render(bool isMine, Model::RenderMode renderMode) {
     _renderAlpha = 1.0;
     
-    if (Menu::getInstance()->isOptionChecked(MenuOption::RenderSkeletonCollisionShapes)) {
+    if (renderMode != Model::SHADOW_RENDER_MODE && 
+                Menu::getInstance()->isOptionChecked(MenuOption::RenderSkeletonCollisionShapes)) {
         // draw a green sphere at hand joint location, which is actually near the wrist)
         for (size_t i = 0; i < getNumPalms(); i++) {
             PalmData& palm = getPalms()[i];
@@ -212,7 +212,7 @@ void Hand::render(bool isMine) {
         }
     }
     
-    if (Menu::getInstance()->isOptionChecked(MenuOption::DisplayHands)) {
+    if (renderMode != Model::SHADOW_RENDER_MODE && Menu::getInstance()->isOptionChecked(MenuOption::DisplayHands)) {
         renderLeapHands(isMine);
     }
 
diff --git a/interface/src/avatar/Hand.h b/interface/src/avatar/Hand.h
index 65a7dcb74a..757a74db29 100755
--- a/interface/src/avatar/Hand.h
+++ b/interface/src/avatar/Hand.h
@@ -24,6 +24,7 @@
 #include <HandData.h>
 
 #include "InterfaceConfig.h"
+#include "renderer/Model.h"
 #include "world.h"
 
 
@@ -52,7 +53,7 @@ public:
     void init();
     void reset();
     void simulate(float deltaTime, bool isMine);
-    void render(bool isMine);
+    void render(bool isMine, Model::RenderMode renderMode = Model::DEFAULT_RENDER_MODE);
 
     // getters
     const glm::vec3& getLeapFingerTipBallPosition (int ball) const { return _leapFingerTipBalls [ball].position;}
diff --git a/interface/src/avatar/Head.cpp b/interface/src/avatar/Head.cpp
index 19aebba25c..9cb8ea3d9c 100644
--- a/interface/src/avatar/Head.cpp
+++ b/interface/src/avatar/Head.cpp
@@ -182,7 +182,7 @@ void Head::relaxLean(float deltaTime) {
 }
 
 void Head::render(float alpha, Model::RenderMode mode) {
-    if (_faceModel.render(alpha, mode) && _renderLookatVectors) {
+    if (_faceModel.render(alpha, mode) && _renderLookatVectors && mode != Model::SHADOW_RENDER_MODE) {
         renderLookatVectors(_leftEyePosition, _rightEyePosition, _lookAtPosition);
     }
 }
diff --git a/interface/src/avatar/MyAvatar.cpp b/interface/src/avatar/MyAvatar.cpp
index 34d256626b..1655a17f08 100644
--- a/interface/src/avatar/MyAvatar.cpp
+++ b/interface/src/avatar/MyAvatar.cpp
@@ -337,7 +337,9 @@ void MyAvatar::render(const glm::vec3& cameraPosition, RenderMode renderMode) {
         return; // exit early
     }
     Avatar::render(cameraPosition, renderMode);
-    if (Menu::getInstance()->isOptionChecked(MenuOption::ShowIKConstraints)) {
+    
+    // don't display IK constraints in shadow mode
+    if (Menu::getInstance()->isOptionChecked(MenuOption::ShowIKConstraints) && renderMode != SHADOW_RENDER_MODE) {
         _skeletonModel.renderIKConstraints();
     }
 }
@@ -586,7 +588,7 @@ void MyAvatar::renderBody(RenderMode renderMode, float glowLevel) {
     if (shouldRenderHead(Application::getInstance()->getCamera()->getPosition(), renderMode)) {
         getHead()->render(1.0f, modelRenderMode);
     }
-    getHand()->render(true);
+    getHand()->render(true, modelRenderMode);
 }
 
 const float RENDER_HEAD_CUTOFF_DISTANCE = 0.50f;
diff --git a/interface/src/models/ModelTreeRenderer.cpp b/interface/src/models/ModelTreeRenderer.cpp
index 9546c7d1c4..c762182290 100644
--- a/interface/src/models/ModelTreeRenderer.cpp
+++ b/interface/src/models/ModelTreeRenderer.cpp
@@ -39,8 +39,8 @@ void ModelTreeRenderer::update() {
     }
 }
 
-void ModelTreeRenderer::render() {
-    OctreeRenderer::render();
+void ModelTreeRenderer::render(RenderMode renderMode) {
+    OctreeRenderer::render(renderMode);
 }
 
 Model* ModelTreeRenderer::getModel(const QString& url) {
@@ -66,54 +66,130 @@ void ModelTreeRenderer::renderElement(OctreeElement* element, RenderArgs* args)
     const QList<ModelItem>& modelItems = modelTreeElement->getModels();
 
     uint16_t numberOfModels = modelItems.size();
+    
+    bool isShadowMode = args->_renderMode == OctreeRenderer::SHADOW_RENDER_MODE;
+
+    bool displayModelBounds = Menu::getInstance()->isOptionChecked(MenuOption::DisplayModelBounds);
+    bool displayElementProxy = Menu::getInstance()->isOptionChecked(MenuOption::DisplayModelElementProxy);
+    bool displayElementChildProxies = Menu::getInstance()->isOptionChecked(MenuOption::DisplayModelElementChildProxies);
+
+
+    if (!isShadowMode && displayElementProxy && numberOfModels > 0) {
+        glm::vec3 elementCenter = modelTreeElement->getAABox().calcCenter() * (float)TREE_SCALE;
+        float elementSize = modelTreeElement->getScale() * (float)TREE_SCALE;
+        glColor3f(1.0f, 0.0f, 0.0f);
+        glPushMatrix();
+            glTranslatef(elementCenter.x, elementCenter.y, elementCenter.z);
+            glutWireCube(elementSize);
+        glPopMatrix();
+
+        if (displayElementChildProxies) {
+            // draw the children
+            float halfSize = elementSize / 2.0f;
+            float quarterSize = elementSize / 4.0f;
+            glColor3f(1.0f, 1.0f, 0.0f);
+            glPushMatrix();
+                glTranslatef(elementCenter.x - quarterSize, elementCenter.y - quarterSize, elementCenter.z - quarterSize);
+                glutWireCube(halfSize);
+            glPopMatrix();
+
+            glColor3f(1.0f, 0.0f, 1.0f);
+            glPushMatrix();
+                glTranslatef(elementCenter.x + quarterSize, elementCenter.y - quarterSize, elementCenter.z - quarterSize);
+                glutWireCube(halfSize);
+            glPopMatrix();
+
+            glColor3f(0.0f, 1.0f, 0.0f);
+            glPushMatrix();
+                glTranslatef(elementCenter.x - quarterSize, elementCenter.y + quarterSize, elementCenter.z - quarterSize);
+                glutWireCube(halfSize);
+            glPopMatrix();
+
+            glColor3f(0.0f, 0.0f, 1.0f);
+            glPushMatrix();
+                glTranslatef(elementCenter.x - quarterSize, elementCenter.y - quarterSize, elementCenter.z + quarterSize);
+                glutWireCube(halfSize);
+            glPopMatrix();
+
+            glColor3f(1.0f, 1.0f, 1.0f);
+            glPushMatrix();
+                glTranslatef(elementCenter.x + quarterSize, elementCenter.y + quarterSize, elementCenter.z + quarterSize);
+                glutWireCube(halfSize);
+            glPopMatrix();
+
+            glColor3f(0.0f, 0.5f, 0.5f);
+            glPushMatrix();
+                glTranslatef(elementCenter.x - quarterSize, elementCenter.y + quarterSize, elementCenter.z + quarterSize);
+                glutWireCube(halfSize);
+            glPopMatrix();
+
+            glColor3f(0.5f, 0.0f, 0.0f);
+            glPushMatrix();
+                glTranslatef(elementCenter.x + quarterSize, elementCenter.y - quarterSize, elementCenter.z + quarterSize);
+                glutWireCube(halfSize);
+            glPopMatrix();
+
+            glColor3f(0.0f, 0.5f, 0.0f);
+            glPushMatrix();
+                glTranslatef(elementCenter.x + quarterSize, elementCenter.y + quarterSize, elementCenter.z - quarterSize);
+                glutWireCube(halfSize);
+            glPopMatrix();
+        }
+
+    }
 
     for (uint16_t i = 0; i < numberOfModels; i++) {
         const ModelItem& modelItem = modelItems[i];
         // render modelItem aspoints
-        glm::vec3 position = modelItem.getPosition() * (float)TREE_SCALE;
-        glColor3ub(modelItem.getColor()[RED_INDEX],modelItem.getColor()[GREEN_INDEX],modelItem.getColor()[BLUE_INDEX]);
-        float radius = modelItem.getRadius() * (float)TREE_SCALE;
-        //glm::vec3 center = position + glm::vec3(radius, radius, radius); // center it around the position
+        AABox modelBox = modelItem.getAABox();
+        modelBox.scale(TREE_SCALE);
+        if (args->_viewFrustum->boxInFrustum(modelBox) != ViewFrustum::OUTSIDE) {
+            glm::vec3 position = modelItem.getPosition() * (float)TREE_SCALE;
+            float radius = modelItem.getRadius() * (float)TREE_SCALE;
+            float size = modelItem.getSize() * (float)TREE_SCALE;
 
-        bool drawAsModel = modelItem.hasModel();
+            bool drawAsModel = modelItem.hasModel();
 
-        args->_renderedItems++;
+            args->_renderedItems++;
 
-        if (drawAsModel) {
-            glPushMatrix();
-                const float alpha = 1.0f;
+            if (drawAsModel) {
+                glPushMatrix();
+                    const float alpha = 1.0f;
                 
-                Model* model = getModel(modelItem.getModelURL());
+                    Model* model = getModel(modelItem.getModelURL());
 
-                model->setScaleToFit(true, radius * 2.0f);
-                model->setSnapModelToCenter(true);
+                    model->setScaleToFit(true, radius * 2.0f);
+                    model->setSnapModelToCenter(true);
                 
-                // set the rotation
-                glm::quat rotation = modelItem.getModelRotation();
-                model->setRotation(rotation);
+                    // set the rotation
+                    glm::quat rotation = modelItem.getModelRotation();
+                    model->setRotation(rotation);
                 
-                // set the position
-                model->setTranslation(position);
+                    // set the position
+                    model->setTranslation(position);
+                    model->simulate(0.0f);
 
-                model->simulate(0.0f);
+                    // TODO: should we allow modelItems to have alpha on their models?
+                    Model::RenderMode modelRenderMode = args->_renderMode == OctreeRenderer::SHADOW_RENDER_MODE 
+                                                            ? Model::SHADOW_RENDER_MODE : Model::DEFAULT_RENDER_MODE;
+                    model->render(alpha, modelRenderMode);
 
+                    if (!isShadowMode && displayModelBounds) {
+                        glColor3f(0.0f, 1.0f, 0.0f);
+                        glPushMatrix();
+                            glTranslatef(position.x, position.y, position.z);
+                            glutWireCube(size);
+                        glPopMatrix();
+                    }
 
-                model->render(alpha); // TODO: should we allow modelItems to have alpha on their models?
-
-                const bool wantDebugSphere = false;
-                if (wantDebugSphere) {
-                    glPushMatrix();
-                        glTranslatef(position.x, position.y, position.z);
-                        glutWireSphere(radius, 15, 15);
-                    glPopMatrix();
-                }
-
-            glPopMatrix();
-        } else {
-            glPushMatrix();
-                glTranslatef(position.x, position.y, position.z);
-                glutSolidSphere(radius, 15, 15);
-            glPopMatrix();
+                glPopMatrix();
+            } else {
+                glColor3ub(modelItem.getColor()[RED_INDEX],modelItem.getColor()[GREEN_INDEX],modelItem.getColor()[BLUE_INDEX]);
+                glPushMatrix();
+                    glTranslatef(position.x, position.y, position.z);
+                    glutSolidSphere(radius, 15, 15);
+                glPopMatrix();
+            }
         }
     }
 }
diff --git a/interface/src/models/ModelTreeRenderer.h b/interface/src/models/ModelTreeRenderer.h
index 5ed4720391..7af5bbf317 100644
--- a/interface/src/models/ModelTreeRenderer.h
+++ b/interface/src/models/ModelTreeRenderer.h
@@ -46,7 +46,7 @@ public:
     void processEraseMessage(const QByteArray& dataByteArray, const SharedNodePointer& sourceNode);
 
     virtual void init();
-    virtual void render();
+    virtual void render(RenderMode renderMode = DEFAULT_RENDER_MODE);
 
 protected:
     Model* getModel(const QString& url);
diff --git a/interface/src/particles/ParticleTreeRenderer.cpp b/interface/src/particles/ParticleTreeRenderer.cpp
index aa498082d9..2983093564 100644
--- a/interface/src/particles/ParticleTreeRenderer.cpp
+++ b/interface/src/particles/ParticleTreeRenderer.cpp
@@ -39,8 +39,8 @@ void ParticleTreeRenderer::update() {
     }
 }
 
-void ParticleTreeRenderer::render() {
-    OctreeRenderer::render();
+void ParticleTreeRenderer::render(RenderMode renderMode) {
+    OctreeRenderer::render(renderMode);
 }
 
 Model* ParticleTreeRenderer::getModel(const QString& url) {
@@ -102,7 +102,11 @@ void ParticleTreeRenderer::renderElement(OctreeElement* element, RenderArgs* arg
                 model->setScale(scale * MODEL_SCALE * radius * modelScale);
 
                 model->simulate(0.0f);
-                model->render(alpha); // TODO: should we allow particles to have alpha on their models?
+
+                // TODO: should we allow particles to have alpha on their models?
+                Model::RenderMode modelRenderMode = args->_renderMode == OctreeRenderer::SHADOW_RENDER_MODE 
+                                                        ? Model::SHADOW_RENDER_MODE : Model::DEFAULT_RENDER_MODE;
+                model->render(alpha, modelRenderMode);
 
                 const bool wantDebugSphere = false;
                 if (wantDebugSphere) {
diff --git a/interface/src/particles/ParticleTreeRenderer.h b/interface/src/particles/ParticleTreeRenderer.h
index ea52df3932..ccb8bfbdf3 100644
--- a/interface/src/particles/ParticleTreeRenderer.h
+++ b/interface/src/particles/ParticleTreeRenderer.h
@@ -43,7 +43,7 @@ public:
     void processEraseMessage(const QByteArray& dataByteArray, const SharedNodePointer& sourceNode);
 
     virtual void init();
-    virtual void render();
+    virtual void render(RenderMode renderMode = DEFAULT_RENDER_MODE);
 
 protected:
     Model* getModel(const QString& url);
diff --git a/libraries/models/src/ModelItem.h b/libraries/models/src/ModelItem.h
index 76a78122ff..9edcf482c0 100644
--- a/libraries/models/src/ModelItem.h
+++ b/libraries/models/src/ModelItem.h
@@ -85,6 +85,9 @@ public:
     
     /// used by ModelScriptingInterface to return ModelItemProperties for unknown models
     void setIsUnknownID() { _id = UNKNOWN_MODEL_ID; _idSet = true; }
+    
+    glm::vec3 getMinimumPoint() const { return _position - glm::vec3(_radius, _radius, _radius); }
+    glm::vec3 getMaximumPoint() const { return _position + glm::vec3(_radius, _radius, _radius); }
 
 private:
     glm::vec3 _position;
@@ -156,11 +159,20 @@ public:
     /// get position in domain scale units (0.0 - 1.0)
     const glm::vec3& getPosition() const { return _position; }
 
+    glm::vec3 getMinimumPoint() const { return _position - glm::vec3(_radius, _radius, _radius); }
+    glm::vec3 getMaximumPoint() const { return _position + glm::vec3(_radius, _radius, _radius); }
+
     const rgbColor& getColor() const { return _color; }
     xColor getXColor() const { xColor color = { _color[RED_INDEX], _color[GREEN_INDEX], _color[BLUE_INDEX] }; return color; }
 
     /// get radius in domain scale units (0.0 - 1.0)
     float getRadius() const { return _radius; }
+
+    /// get maximum dimension in domain scale units (0.0 - 1.0)
+    float getSize() const { return _radius * 2.0f; }
+
+    /// get maximum dimension in domain scale units (0.0 - 1.0)
+    AABox getAABox() const { return AABox(getMinimumPoint(), getSize()); }
     
     // model related properties
     bool hasModel() const { return !_modelURL.isEmpty(); }
diff --git a/libraries/models/src/ModelTree.cpp b/libraries/models/src/ModelTree.cpp
index cef38a9422..45694b081d 100644
--- a/libraries/models/src/ModelTree.cpp
+++ b/libraries/models/src/ModelTree.cpp
@@ -113,13 +113,10 @@ void ModelTree::storeModel(const ModelItem& model, const SharedNodePointer& send
     FindAndUpdateModelOperator theOperator(model);
     recurseTreeWithOperator(&theOperator);
     
-
     // if we didn't find it in the tree, then store it...
     if (!theOperator.wasFound()) {
-        glm::vec3 position = model.getPosition();
-        float size = std::max(MINIMUM_MODEL_ELEMENT_SIZE, model.getRadius());
-
-        ModelTreeElement* element = (ModelTreeElement*)getOrCreateChildElementAt(position.x, position.y, position.z, size);
+        AABox modelBox = model.getAABox();
+        ModelTreeElement* element = (ModelTreeElement*)getOrCreateChildElementContaining(model.getAABox());
         element->storeModel(model);
     }
     // what else do we need to do here to get reaveraging to work
@@ -494,12 +491,29 @@ void ModelTree::update() {
     lockForWrite();
     _isDirty = true;
 
-    // TODO: we don't need to update models yet, but when we do, for example 
-    // when we add animation support, we will revisit this code.
-    //ModelTreeUpdateArgs args = { };
-    //recurseTreeWithOperation(updateOperation, &args);
+    ModelTreeUpdateArgs args = { };
+    recurseTreeWithOperation(updateOperation, &args);
 
-    // Now is a reasonable time to prune the tree...
+    // now add back any of the particles that moved elements....
+    int movingModels = args._movingModels.size();
+    for (int i = 0; i < movingModels; i++) {
+        bool shouldDie = args._movingModels[i].getShouldDie();
+
+        // if the particle is still inside our total bounds, then re-add it
+        AABox treeBounds = getRoot()->getAABox();
+
+        if (!shouldDie && treeBounds.contains(args._movingModels[i].getPosition())) {
+            storeModel(args._movingModels[i]);
+        } else {
+            uint32_t modelItemID = args._movingModels[i].getID();
+            quint64 deletedAt = usecTimestampNow();
+            _recentlyDeletedModelsLock.lockForWrite();
+            _recentlyDeletedModelItemIDs.insert(deletedAt, modelItemID);
+            _recentlyDeletedModelsLock.unlock();
+        }
+    }
+
+    // prune the tree...
     recurseTreeWithOperation(pruneOperation, NULL);
     unlock();
 }
diff --git a/libraries/models/src/ModelTreeElement.cpp b/libraries/models/src/ModelTreeElement.cpp
index 0327d8a0c4..5c5d5100cf 100644
--- a/libraries/models/src/ModelTreeElement.cpp
+++ b/libraries/models/src/ModelTreeElement.cpp
@@ -47,15 +47,32 @@ ModelTreeElement* ModelTreeElement::addChildAtIndex(int index) {
 }
 
 
-bool ModelTreeElement::appendElementData(OctreePacketData* packetData) const {
+bool ModelTreeElement::appendElementData(OctreePacketData* packetData, EncodeBitstreamParams& params) const {
     bool success = true; // assume the best...
 
-    // write our models out...
-    uint16_t numberOfModels = _modelItems->size();
+    // write our models out... first determine which of the models are in view based on our params
+    uint16_t numberOfModels = 0;
+    QVector<uint16_t> indexesOfModelsToInclude;
+
+    for (uint16_t i = 0; i < _modelItems->size(); i++) {
+        if (params.viewFrustum) {
+            const ModelItem& model = (*_modelItems)[i];
+            AABox modelBox = model.getAABox();
+            modelBox.scale(TREE_SCALE);
+            if (params.viewFrustum->boxInFrustum(modelBox) != ViewFrustum::OUTSIDE) {
+                indexesOfModelsToInclude << i;
+                numberOfModels++;
+            }
+        } else {
+            indexesOfModelsToInclude << i;
+            numberOfModels++;
+        }
+    }
+
     success = packetData->appendValue(numberOfModels);
 
     if (success) {
-        for (uint16_t i = 0; i < numberOfModels; i++) {
+        foreach (uint16_t i, indexesOfModelsToInclude) {
             const ModelItem& model = (*_modelItems)[i];
             success = model.appendModelData(packetData);
             if (!success) {
@@ -66,10 +83,25 @@ bool ModelTreeElement::appendElementData(OctreePacketData* packetData) const {
     return success;
 }
 
-void ModelTreeElement::update(ModelTreeUpdateArgs& args) {
-    markWithChangedTime();
-    // TODO: early exit when _modelItems is empty
+bool ModelTreeElement::containsModelBounds(const ModelItem& model) const {
+    return _box.contains(model.getMinimumPoint()) && _box.contains(model.getMaximumPoint());
+}
 
+bool ModelTreeElement::bestFitModelBounds(const ModelItem& model) const {
+    if (_box.contains(model.getMinimumPoint()) && _box.contains(model.getMaximumPoint())) {
+        int childForMinimumPoint = getMyChildContainingPoint(model.getMinimumPoint());
+        int childForMaximumPoint = getMyChildContainingPoint(model.getMaximumPoint());
+        
+        // If I contain both the minimum and maximum point, but two different children of mine
+        // contain those points, then I am the best fit for that model
+        if (childForMinimumPoint != childForMaximumPoint) {
+            return true;
+        }
+    }
+    return false;
+}
+
+void ModelTreeElement::update(ModelTreeUpdateArgs& args) {
     // update our contained models
     QList<ModelItem>::iterator modelItr = _modelItems->begin();
     while(modelItr != _modelItems->end()) {
@@ -78,19 +110,18 @@ void ModelTreeElement::update(ModelTreeUpdateArgs& args) {
 
         // If the model wants to die, or if it's left our bounding box, then move it
         // into the arguments moving models. These will be added back or deleted completely
-        if (model.getShouldDie() || !_box.contains(model.getPosition())) {
+        if (model.getShouldDie() || !bestFitModelBounds(model)) {
             args._movingModels.push_back(model);
 
             // erase this model
             modelItr = _modelItems->erase(modelItr);
+            
+            // this element has changed so mark it...
+            markWithChangedTime();
         } else {
             ++modelItr;
         }
     }
-    // TODO: if _modelItems is empty after while loop consider freeing memory in _modelItems if
-    // internal array is too big (QList internal array does not decrease size except in dtor and
-    // assignment operator).  Otherwise _modelItems could become a "resource leak" for large
-    // roaming piles of models.
 }
 
 bool ModelTreeElement::findSpherePenetration(const glm::vec3& center, float radius,
@@ -136,6 +167,7 @@ bool ModelTreeElement::updateModel(const ModelItem& model) {
                             (localOlder ? "OLDER" : "NEWER"),
                             difference, debug::valueOf(model.isNewlyCreated()) );
                 }
+                
                 thisModel.copyChangedProperties(model);
                 markWithChangedTime();
             } else {
diff --git a/libraries/models/src/ModelTreeElement.h b/libraries/models/src/ModelTreeElement.h
index ce03d50065..ce9e2dec7e 100644
--- a/libraries/models/src/ModelTreeElement.h
+++ b/libraries/models/src/ModelTreeElement.h
@@ -74,7 +74,7 @@ public:
     virtual bool requiresSplit() const { return false; }
 
     /// Override to serialize the state of this element. This is used for persistance and for transmission across the network.
-    virtual bool appendElementData(OctreePacketData* packetData) const;
+    virtual bool appendElementData(OctreePacketData* packetData, EncodeBitstreamParams& params) const;
 
     /// Override to deserialize the state of this element. This is used for loading from a persisted file or from reading
     /// from the network.
@@ -118,6 +118,9 @@ public:
 
     bool removeModelWithID(uint32_t id);
 
+    bool containsModelBounds(const ModelItem& model) const;
+    bool bestFitModelBounds(const ModelItem& model) const;
+
 protected:
     virtual void init(unsigned char * octalCode);
 
diff --git a/libraries/octree/src/Octree.cpp b/libraries/octree/src/Octree.cpp
index d308d007cd..5b766ecdd7 100644
--- a/libraries/octree/src/Octree.cpp
+++ b/libraries/octree/src/Octree.cpp
@@ -578,6 +578,10 @@ OctreeElement* Octree::getOrCreateChildElementAt(float x, float y, float z, floa
     return getRoot()->getOrCreateChildElementAt(x, y, z, s);
 }
 
+OctreeElement* Octree::getOrCreateChildElementContaining(const AABox& box) {
+    return getRoot()->getOrCreateChildElementContaining(box);
+}
+
 
 // combines the ray cast arguments into a single object
 class RayArgs {
@@ -1001,7 +1005,7 @@ int Octree::encodeTreeBitstreamRecursion(OctreeElement* element,
     // Keep track of how deep we've encoded.
     currentEncodeLevel++;
 
-    params.maxLevelReached = std::max(currentEncodeLevel,params.maxLevelReached);
+    params.maxLevelReached = std::max(currentEncodeLevel, params.maxLevelReached);
 
     // If we've reached our max Search Level, then stop searching.
     if (currentEncodeLevel >= params.maxEncodeLevel) {
@@ -1342,7 +1346,7 @@ int Octree::encodeTreeBitstreamRecursion(OctreeElement* element,
                 OctreeElement* childElement = element->getChildAtIndex(i);
                 if (childElement) {
                     int bytesBeforeChild = packetData->getUncompressedSize();
-                    continueThisLevel = childElement->appendElementData(packetData);
+                    continueThisLevel = childElement->appendElementData(packetData, params);
                     int bytesAfterChild = packetData->getUncompressedSize();
 
                     if (!continueThisLevel) {
diff --git a/libraries/octree/src/Octree.h b/libraries/octree/src/Octree.h
index 6e0693dc23..4a17cb3c1d 100644
--- a/libraries/octree/src/Octree.h
+++ b/libraries/octree/src/Octree.h
@@ -227,6 +227,7 @@ public:
     OctreeElement* getOctreeEnclosingElementAt(float x, float y, float z, float s) const;
     
     OctreeElement* getOrCreateChildElementAt(float x, float y, float z, float s);
+    OctreeElement* getOrCreateChildElementContaining(const AABox& box);
 
     void recurseTreeWithOperation(RecurseOctreeOperation operation, void* extraData = NULL);
     void recurseTreeWithPostOperation(RecurseOctreeOperation operation, void* extraData = NULL);
diff --git a/libraries/octree/src/OctreeElement.cpp b/libraries/octree/src/OctreeElement.cpp
index d54f7aa94b..edba26f2a7 100644
--- a/libraries/octree/src/OctreeElement.cpp
+++ b/libraries/octree/src/OctreeElement.cpp
@@ -1379,3 +1379,90 @@ OctreeElement* OctreeElement::getOrCreateChildElementAt(float x, float y, float
     // Now that we have the child to recurse down, let it answer the original question...
     return child->getOrCreateChildElementAt(x, y, z, s);
 }
+
+
+OctreeElement* OctreeElement::getOrCreateChildElementContaining(const AABox& box) {
+    OctreeElement* child = NULL;
+    
+    float ourScale = getScale();
+    float boxScale = box.getScale();
+
+    if(boxScale > ourScale) {
+        qDebug("UNEXPECTED -- OctreeElement::getOrCreateChildElementContaining() "
+                    "boxScale=[%f] > ourScale=[%f] ", boxScale, ourScale);
+    }
+
+    // Determine which of our children the minimum and maximum corners of the box live in...
+    glm::vec3 boxCornerMinimum = box.getCorner();
+    glm::vec3 boxCornerMaximum = box.calcTopFarLeft();
+
+    int childIndexBoxMinimum = getMyChildContainingPoint(boxCornerMinimum);
+    int childIndexBoxMaximum = getMyChildContainingPoint(boxCornerMaximum);
+
+    // If the minimum and maximum corners of the box are in two different children's boxes, then we are the containing element
+    if (childIndexBoxMinimum != childIndexBoxMaximum) {
+        return this;
+    }
+
+    // otherwise, they are the same and that child should be considered as the correct element    
+    int childIndex = childIndexBoxMinimum; // both the same...
+    
+    // Now, check if we have a child at that location
+    child = getChildAtIndex(childIndex);
+    if (!child) {
+        child = addChildAtIndex(childIndex);
+    }
+
+    // Now that we have the child to recurse down, let it answer the original question...
+    return child->getOrCreateChildElementContaining(box);
+}
+
+int OctreeElement::getMyChildContainingPoint(const glm::vec3& point) const {
+    glm::vec3 ourCenter = _box.calcCenter();
+    int childIndex = CHILD_UNKNOWN;
+    // left half
+    if (point.x > ourCenter.x) {
+        if (point.y > ourCenter.y) {
+            // top left
+            if (point.z > ourCenter.z) {
+                // top left far
+                childIndex = CHILD_TOP_LEFT_FAR;
+            } else {
+                // top left near
+                childIndex = CHILD_TOP_LEFT_NEAR;
+            }
+        } else {
+            // bottom left
+            if (point.z > ourCenter.z) {
+                // bottom left far
+                childIndex = CHILD_BOTTOM_LEFT_FAR;
+            } else {
+                // bottom left near
+                childIndex = CHILD_BOTTOM_LEFT_NEAR;
+            }
+        }
+    } else {
+        // right half
+        if (point.y > ourCenter.y) {
+            // top right
+            if (point.z > ourCenter.z) {
+                // top right far
+                childIndex = CHILD_TOP_RIGHT_FAR;
+            } else {
+                // top right near
+                childIndex = CHILD_TOP_RIGHT_NEAR;
+            }
+        } else {
+            // bottom right
+            if (point.z > ourCenter.z) {
+                // bottom right far
+                childIndex = CHILD_BOTTOM_RIGHT_FAR;
+            } else {
+                // bottom right near
+                childIndex = CHILD_BOTTOM_RIGHT_NEAR;
+            }
+        }
+    }
+    return childIndex;
+}
+
diff --git a/libraries/octree/src/OctreeElement.h b/libraries/octree/src/OctreeElement.h
index c5eec1c9e2..42c9abad46 100644
--- a/libraries/octree/src/OctreeElement.h
+++ b/libraries/octree/src/OctreeElement.h
@@ -23,14 +23,14 @@
 #include "AABox.h"
 #include "ViewFrustum.h"
 #include "OctreeConstants.h"
-//#include "Octree.h"
 
+class EncodeBitstreamParams;
 class Octree;
 class OctreeElement;
 class OctreeElementDeleteHook;
 class OctreePacketData;
-class VoxelSystem;
 class ReadBitstreamToTreeParams;
+class VoxelSystem;
 
 // Callers who want delete hook callbacks should implement this class
 class OctreeElementDeleteHook {
@@ -81,7 +81,7 @@ public:
     virtual bool requiresSplit() const { return false; }
 
     /// Override to serialize the state of this element. This is used for persistance and for transmission across the network.
-    virtual bool appendElementData(OctreePacketData* packetData) const { return true; }
+    virtual bool appendElementData(OctreePacketData* packetData, EncodeBitstreamParams& params) const { return true; }
     
     /// Override to deserialize the state of this element. This is used for loading from a persisted file or from reading
     /// from the network.
@@ -217,6 +217,8 @@ public:
 
 
     OctreeElement* getOrCreateChildElementAt(float x, float y, float z, float s);
+    OctreeElement* getOrCreateChildElementContaining(const AABox& box);
+    int getMyChildContainingPoint(const glm::vec3& point) const;
 
 protected:
 
diff --git a/libraries/octree/src/OctreeHeadlessViewer.h b/libraries/octree/src/OctreeHeadlessViewer.h
index ebabf1dbad..3509713d50 100644
--- a/libraries/octree/src/OctreeHeadlessViewer.h
+++ b/libraries/octree/src/OctreeHeadlessViewer.h
@@ -33,7 +33,7 @@ public:
     virtual void renderElement(OctreeElement* element, RenderArgs* args) { /* swallow these */ };
 
     virtual void init();
-    virtual void render() { /* swallow these */ };
+    virtual void render(RenderMode renderMode = DEFAULT_RENDER_MODE) { /* swallow these */ };
 
     void setJurisdictionListener(JurisdictionListener* jurisdictionListener) { _jurisdictionListener = jurisdictionListener; }
 
diff --git a/libraries/octree/src/OctreeRenderer.cpp b/libraries/octree/src/OctreeRenderer.cpp
index 5c5da2250f..c1ce3cb218 100644
--- a/libraries/octree/src/OctreeRenderer.cpp
+++ b/libraries/octree/src/OctreeRenderer.cpp
@@ -154,8 +154,8 @@ bool OctreeRenderer::renderOperation(OctreeElement* element, void* extraData) {
     return false;
 }
 
-void OctreeRenderer::render() {
-    RenderArgs args = { 0, this, _viewFrustum, getSizeScale(), getBoundaryLevelAdjust() };
+void OctreeRenderer::render(RenderMode renderMode) {
+    RenderArgs args = { 0, this, _viewFrustum, getSizeScale(), getBoundaryLevelAdjust(), renderMode };
     if (_tree) {
         _tree->lockForRead();
         _tree->recurseTreeWithOperation(renderOperation, &args);
diff --git a/libraries/octree/src/OctreeRenderer.h b/libraries/octree/src/OctreeRenderer.h
index 652f9d0399..73e26c97f6 100644
--- a/libraries/octree/src/OctreeRenderer.h
+++ b/libraries/octree/src/OctreeRenderer.h
@@ -25,15 +25,7 @@
 #include "ViewFrustum.h"
 
 class OctreeRenderer;
-
-class RenderArgs {
-public:
-    int _renderedItems;
-    OctreeRenderer* _renderer;
-    ViewFrustum* _viewFrustum;
-    float _sizeScale;
-    int _boundaryLevelAdjust;
-};
+class RenderArgs;
 
 
 // Generic client side Octree renderer class.
@@ -59,8 +51,10 @@ public:
     /// initialize and GPU/rendering related resources
     virtual void init();
 
+    enum RenderMode { DEFAULT_RENDER_MODE, SHADOW_RENDER_MODE, DIFFUSE_RENDER_MODE, NORMAL_RENDER_MODE };
+
     /// render the content of the octree
-    virtual void render();
+    virtual void render(RenderMode renderMode = DEFAULT_RENDER_MODE);
 
     ViewFrustum* getViewFrustum() const { return _viewFrustum; }
     void setViewFrustum(ViewFrustum* viewFrustum) { _viewFrustum = viewFrustum; }
@@ -75,4 +69,15 @@ protected:
     ViewFrustum* _viewFrustum;
 };
 
+class RenderArgs {
+public:
+    int _renderedItems;
+    OctreeRenderer* _renderer;
+    ViewFrustum* _viewFrustum;
+    float _sizeScale;
+    int _boundaryLevelAdjust;
+    OctreeRenderer::RenderMode _renderMode;
+};
+
+
 #endif // hifi_OctreeRenderer_h
diff --git a/libraries/particles/src/ParticleTreeElement.cpp b/libraries/particles/src/ParticleTreeElement.cpp
index d28ccf2f5e..b6e59eb0ab 100644
--- a/libraries/particles/src/ParticleTreeElement.cpp
+++ b/libraries/particles/src/ParticleTreeElement.cpp
@@ -47,7 +47,7 @@ ParticleTreeElement* ParticleTreeElement::addChildAtIndex(int index) {
 }
 
 
-bool ParticleTreeElement::appendElementData(OctreePacketData* packetData) const {
+bool ParticleTreeElement::appendElementData(OctreePacketData* packetData, EncodeBitstreamParams& params) const {
     bool success = true; // assume the best...
 
     // write our particles out...
diff --git a/libraries/particles/src/ParticleTreeElement.h b/libraries/particles/src/ParticleTreeElement.h
index 59f80d588a..4381cdd777 100644
--- a/libraries/particles/src/ParticleTreeElement.h
+++ b/libraries/particles/src/ParticleTreeElement.h
@@ -76,7 +76,7 @@ public:
     virtual bool requiresSplit() const { return false; }
 
     /// Override to serialize the state of this element. This is used for persistance and for transmission across the network.
-    virtual bool appendElementData(OctreePacketData* packetData) const;
+    virtual bool appendElementData(OctreePacketData* packetData, EncodeBitstreamParams& params) const;
 
     /// Override to deserialize the state of this element. This is used for loading from a persisted file or from reading
     /// from the network.
diff --git a/libraries/voxels/src/VoxelTreeElement.cpp b/libraries/voxels/src/VoxelTreeElement.cpp
index 2582980816..f72e628b74 100644
--- a/libraries/voxels/src/VoxelTreeElement.cpp
+++ b/libraries/voxels/src/VoxelTreeElement.cpp
@@ -65,7 +65,7 @@ void VoxelTreeElement::splitChildren() {
     }
 }
 
-bool VoxelTreeElement::appendElementData(OctreePacketData* packetData) const {
+bool VoxelTreeElement::appendElementData(OctreePacketData* packetData, EncodeBitstreamParams& params) const {
     return packetData->appendColor(getColor());
 }
 
diff --git a/libraries/voxels/src/VoxelTreeElement.h b/libraries/voxels/src/VoxelTreeElement.h
index 8733987df4..788a728f6f 100644
--- a/libraries/voxels/src/VoxelTreeElement.h
+++ b/libraries/voxels/src/VoxelTreeElement.h
@@ -43,7 +43,7 @@ public:
     virtual bool hasContent() const { return isColored(); }
     virtual void splitChildren();
     virtual bool requiresSplit() const;
-    virtual bool appendElementData(OctreePacketData* packetData) const;
+    virtual bool appendElementData(OctreePacketData* packetData, EncodeBitstreamParams& params) const;
     virtual int readElementDataFromBuffer(const unsigned char* data, int bytesLeftToRead, ReadBitstreamToTreeParams& args);
     virtual void calculateAverageFromChildren();
     virtual bool collapseChildren();