diff --git a/examples/html/entityProperties.html b/examples/html/entityProperties.html
index a2ff71d010..7c214624c2 100644
--- a/examples/html/entityProperties.html
+++ b/examples/html/entityProperties.html
@@ -287,6 +287,18 @@
             allSections.push(elWebSections);
             var elWebSourceURL = document.getElementById("property-web-source-url");
 
+            var elParticleSections = document.querySelectorAll(".particle-section");
+            allSections.push(elParticleSections);
+            var elParticleMaxParticles = document.getElementById("property-particle-maxparticles");
+            var elParticleLifeSpan = document.getElementById("property-particle-lifespan");
+            var elParticleEmitRate = document.getElementById("property-particle-emit-rate");
+            var elParticleEmitDirectionX = document.getElementById("property-particle-emit-direction-x");
+            var elParticleEmitDirectionY = document.getElementById("property-particle-emit-direction-y");
+            var elParticleEmitDirectionZ = document.getElementById("property-particle-emit-direction-z");
+            var elParticleEmitStrength = document.getElementById("property-particle-emit-strength");
+            var elParticleLocalGravity = document.getElementById("property-particle-localgravity");
+            var elParticleRadius = document.getElementById("property-particle-radius");
+
             var elTextSections = document.querySelectorAll(".text-section");
             allSections.push(elTextSections);
             var elTextText = document.getElementById("property-text-text");
@@ -455,7 +467,7 @@
                                 }
                             }
 
-                            if (properties.type == "Box" || properties.type == "Sphere") {
+                            if (properties.type == "Box" || properties.type == "Sphere" || properties.type == "ParticleEffect") {
                                 elColorSection.style.display = 'block';
                                 elColorRed.value = properties.color.red;
                                 elColorGreen.value = properties.color.green;
@@ -465,7 +477,7 @@
                                 elColorSection.style.display = 'none';
                             }
 
-                            if (properties.type == "Model") {
+                            if (properties.type == "Model" || properties.type == "ParticleEffect") {
                                 for (var i = 0; i < elModelSections.length; i++) {
                                     elModelSections[i].style.display = 'block';
                                 }
@@ -479,7 +491,7 @@
                                 elModelAnimationFrame.value = properties.animationFrameIndex;
                                 elModelAnimationSettings.value = properties.animationSettings;
                                 elModelTextures.value = properties.textures;
-                                elModelOriginalTextures.value = properties.originalTextures;
+                                elModelOriginalTextures.value = properties.originalTextures;  
                             } else if (properties.type == "Web") {
                                 for (var i = 0; i < elWebSections.length; i++) {
                                     elWebSections[i].style.display = 'block';
@@ -562,6 +574,20 @@
                                 
                                 showElements(document.getElementsByClassName('skybox-section'), elZoneBackgroundMode.value == 'skybox');
                                 showElements(document.getElementsByClassName('atmosphere-section'), elZoneBackgroundMode.value == 'atmosphere');
+                            } else if (properties.type == "ParticleEffect") {
+                                for (var i = 0; i < elParticleSections.length; i++) {
+                                    elParticleSections[i].style.display = 'block';
+                                }
+
+                                elParticleMaxParticles.value = properties.maxParticles;
+                                elParticleLifeSpan.value = properties.lifespan.toFixed(2);
+                                elParticleEmitRate.value = properties.emitRate.toFixed(1);
+                                elParticleEmitDirectionX.value = properties.emitDirection.x.toFixed(2);
+                                elParticleEmitDirectionY.value = properties.emitDirection.y.toFixed(2);
+                                elParticleEmitDirectionZ.value = properties.emitDirection.z.toFixed(2);
+                                elParticleEmitStrength.value = properties.emitStrength.toFixed(2);
+                                elParticleLocalGravity.value = properties.localGravity.toFixed(2);
+                                elParticleRadius.value = properties.particleRadius.toFixed(3);
                             }
 
                             if (selected) {
@@ -678,6 +704,18 @@
             elLightCutoff.addEventListener('change', createEmitNumberPropertyUpdateFunction('cutoff'));
 
             elWebSourceURL.addEventListener('change', createEmitTextPropertyUpdateFunction('sourceUrl'));
+            
+            elParticleMaxParticles.addEventListener('change', createEmitNumberPropertyUpdateFunction('maxParticles'));
+            elParticleLifeSpan.addEventListener('change', createEmitNumberPropertyUpdateFunction('lifespan'));
+            elParticleEmitRate.addEventListener('change', createEmitNumberPropertyUpdateFunction('emitRate'));
+            var particleEmitDirectionChangeFunction = createEmitVec3PropertyUpdateFunctionWithMultiplier(
+                'emitDirection', elParticleEmitDirectionX, elParticleEmitDirectionY, elParticleEmitDirectionZ, DEGREES_TO_RADIANS);
+            elParticleEmitDirectionX.addEventListener('change', particleEmitDirectionChangeFunction);
+            elParticleEmitDirectionY.addEventListener('change', particleEmitDirectionChangeFunction);
+            elParticleEmitDirectionZ.addEventListener('change', particleEmitDirectionChangeFunction);
+            elParticleEmitStrength.addEventListener('change', createEmitNumberPropertyUpdateFunction('emitStrength'));
+            elParticleLocalGravity.addEventListener('change', createEmitNumberPropertyUpdateFunction('localGravity'));
+            elParticleRadius.addEventListener('change', createEmitNumberPropertyUpdateFunction('particleRadius'));
 
             elModelURL.addEventListener('change', createEmitTextPropertyUpdateFunction('modelURL'));
             elShapeType.addEventListener('change', createEmitTextPropertyUpdateFunction('shapeType'));
@@ -1069,7 +1107,52 @@
                 <input type="text" id="property-web-source-url" class="url"></input>
             </div>
         </div>
-
+        
+        <div class="particle-section property">
+            <div class="label">Max Particles</div>
+            <div class="value">
+                <input type='number' id="property-particle-maxparticles" min="0" max="2048" step="1"></input>
+            </div>
+        </div>        
+        <div class="particle-section property">
+            <div class="label">Particle Life Span</div>
+            <div class="value">
+                <input type='number' id="property-particle-lifespan" min="0" step="0.1"></input>
+            </div>
+        </div>        
+        <div class="particle-section property">
+            <div class="label">Particle Emission Rate</div>
+            <div class="value">
+                <input type='number' id="property-particle-emit-rate" min="0" step="0.5"></input>
+            </div>
+        </div>
+        <div class="particle-section property">
+            <div class="label">Particle Emission Direction</div>
+            <div class="value">
+                <div class="input-area">X <input class="coord" type='number' id="property-particle-emit-direction-x"></input></div>
+                <div class="input-area">Y <input class="coord" type='number' id="property-particle-emit-direction-y"></input></div>
+                <div class="input-area">Z <input class="coord" type='number' id="property-particle-emit-direction-z"></input></div>
+            </div>
+        </div>
+        <div class="particle-section property">
+            <div class="label">Particle Emission Strength</div>
+            <div class="value">
+                <input type='number' id="property-particle-emit-strength" min="0" step="0.1"></input>
+            </div>
+        </div>
+        <div class="particle-section property">
+            <div class="label">Particle Local Gravity</div>
+            <div class="value">
+                <input class="coord" type='number' id="property-particle-localgravity" step="0.05"></input>
+            </div>
+        </div>
+        <div class="particle-section property">
+            <div class="label">Particle Radius</div>
+            <div class="value">
+                <input  class="coord" type='number' id="property-particle-radius" min="0" step="0.005"></input>
+            </div>
+        </div>
+        
         <div class="model-section property">
             <div class="label">Model URL</div>
             <div class="value">
diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index ef1aa2cced..36cea02bf0 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -693,6 +693,10 @@ Application::~Application() {
     // stop the glWidget frame timer so it doesn't call paintGL
     _glWidget->stopFrameTimer();
 
+    // remove avatars from physics engine
+    DependencyManager::get<AvatarManager>()->clearOtherAvatars();
+    _physicsEngine.deleteObjects(DependencyManager::get<AvatarManager>()->getObjectsToDelete());
+
     DependencyManager::destroy<OffscreenUi>();
     DependencyManager::destroy<AvatarManager>();
     DependencyManager::destroy<AnimationCache>();
@@ -2166,7 +2170,7 @@ void Application::init() {
     _physicsEngine.init();
 
     EntityTree* tree = _entities.getTree();
-    _entitySimulation.init(tree, &_physicsEngine, &_shapeManager, &_entityEditSender);
+    _entitySimulation.init(tree, &_physicsEngine, &_entityEditSender);
     tree->setSimulation(&_entitySimulation);
 
     auto entityScriptingInterface = DependencyManager::get<EntityScriptingInterface>();
@@ -2486,12 +2490,21 @@ void Application::update(float deltaTime) {
         _physicsEngine.changeObjects(_entitySimulation.getObjectsToChange());
         _entitySimulation.unlock();
 
+        AvatarManager* avatarManager = DependencyManager::get<AvatarManager>().data();
+        _physicsEngine.deleteObjects(avatarManager->getObjectsToDelete());
+        _physicsEngine.addObjects(avatarManager->getObjectsToAdd());
+        _physicsEngine.changeObjects(avatarManager->getObjectsToChange());
+
         _physicsEngine.stepSimulation();
 
         if (_physicsEngine.hasOutgoingChanges()) {
             _entitySimulation.lock();
             _entitySimulation.handleOutgoingChanges(_physicsEngine.getOutgoingChanges(), _physicsEngine.getSessionID());
             _entitySimulation.unlock();
+
+            avatarManager->handleOutgoingChanges(_physicsEngine.getOutgoingChanges());
+            avatarManager->handleCollisionEvents(_physicsEngine.getCollisionEvents());
+
             _physicsEngine.dumpStatsIfNecessary();
         }
     }
diff --git a/interface/src/avatar/Avatar.cpp b/interface/src/avatar/Avatar.cpp
index bf554f25bf..4d950d4386 100644
--- a/interface/src/avatar/Avatar.cpp
+++ b/interface/src/avatar/Avatar.cpp
@@ -38,6 +38,7 @@
 #include "Application.h"
 #include "Avatar.h"
 #include "AvatarManager.h"
+#include "AvatarMotionState.h"
 #include "Hand.h"
 #include "Head.h"
 #include "Menu.h"
@@ -969,6 +970,9 @@ int Avatar::parseDataAtOffset(const QByteArray& packet, int offset) {
 
     const float MOVE_DISTANCE_THRESHOLD = 0.001f;
     _moving = glm::distance(oldPosition, _position) > MOVE_DISTANCE_THRESHOLD;
+    if (_moving && _motionState) {
+        _motionState->addDirtyFlags(EntityItem::DIRTY_POSITION);
+    }
 
     return bytesRead;
 }
@@ -1084,20 +1088,15 @@ void Avatar::setShowDisplayName(bool showDisplayName) {
 
 }
 
-// virtual
-void Avatar::rebuildSkeletonBody() {
-    /* TODO: implement this and remove override from MyAvatar (when we have AvatarMotionStates working)
-    if (_motionState) {
-        // compute localAABox
-        const CapsuleShape& capsule = _skeletonModel.getBoundingShape();
-        float radius = capsule.getRadius();
-        float height = 2.0f * (capsule.getHalfHeight() + radius);
-        glm::vec3 corner(-radius, -0.5f * height, -radius);
-        corner += _skeletonModel.getBoundingShapeOffset();
-        glm::vec3 scale(2.0f * radius, height, 2.0f * radius);
-        //_characterController.setLocalBoundingBox(corner, scale);
-        _motionState->setBoundingBox(corner, scale);
-    }
-    */
+// virtual 
+void Avatar::computeShapeInfo(ShapeInfo& shapeInfo) {
+    const CapsuleShape& capsule = _skeletonModel.getBoundingShape();
+    shapeInfo.setCapsuleY(capsule.getRadius(), capsule.getHalfHeight());
+    shapeInfo.setOffset(_skeletonModel.getBoundingShapeOffset());
+}
+
+// virtual
+void Avatar::rebuildSkeletonBody() {
+    DependencyManager::get<AvatarManager>()->updateAvatarPhysicsShape(getSessionUUID());
 }
 
diff --git a/interface/src/avatar/Avatar.h b/interface/src/avatar/Avatar.h
index 63c537f1ce..b912a159af 100644
--- a/interface/src/avatar/Avatar.h
+++ b/interface/src/avatar/Avatar.h
@@ -18,11 +18,11 @@
 #include <QtCore/QUuid>
 
 #include <AvatarData.h>
+#include <ShapeInfo.h>
 
 #include "Hand.h"
 #include "Head.h"
 #include "InterfaceConfig.h"
-#include "Recorder.h"
 #include "SkeletonModel.h"
 #include "world.h"
 
@@ -55,6 +55,7 @@ enum ScreenTintLayer {
     NUM_SCREEN_TINT_LAYERS
 };
 
+class AvatarMotionState;
 class Texture;
 
 class Avatar : public AvatarData {
@@ -146,9 +147,9 @@ public:
     
     Q_INVOKABLE glm::vec3 getNeckPosition() const;
 
-    Q_INVOKABLE glm::vec3 getAcceleration() const { return _acceleration; }
-    Q_INVOKABLE glm::vec3 getAngularVelocity() const { return _angularVelocity; }
-    Q_INVOKABLE glm::vec3 getAngularAcceleration() const { return _angularAcceleration; }
+    Q_INVOKABLE const glm::vec3& getAcceleration() const { return _acceleration; }
+    Q_INVOKABLE const glm::vec3& getAngularVelocity() const { return _angularVelocity; }
+    Q_INVOKABLE const glm::vec3& getAngularAcceleration() const { return _angularAcceleration; }
     
 
     /// Scales a world space position vector relative to the avatar position and scale
@@ -164,6 +165,10 @@ public:
 
     virtual void rebuildSkeletonBody();
 
+    virtual void computeShapeInfo(ShapeInfo& shapeInfo);
+
+    friend class AvatarManager;
+
 signals:
     void collisionWithAvatar(const QUuid& myUUID, const QUuid& theirUUID, const CollisionInfo& collision);
 
@@ -231,7 +236,7 @@ private:
 
     int _voiceSphereID;
 
-    //AvatarMotionState* _motionState = nullptr;
+    AvatarMotionState* _motionState = nullptr;
 };
 
 #endif // hifi_Avatar_h
diff --git a/interface/src/avatar/AvatarManager.cpp b/interface/src/avatar/AvatarManager.cpp
index 5d38e89281..2b3b2f2df0 100644
--- a/interface/src/avatar/AvatarManager.cpp
+++ b/interface/src/avatar/AvatarManager.cpp
@@ -92,22 +92,18 @@ void AvatarManager::updateOtherAvatars(float deltaTime) {
     // simulate avatars
     AvatarHash::iterator avatarIterator = _avatarHash.begin();
     while (avatarIterator != _avatarHash.end()) {
-        AvatarSharedPointer sharedAvatar = avatarIterator.value();
-        Avatar* avatar = reinterpret_cast<Avatar*>(sharedAvatar.data());
+        Avatar* avatar = reinterpret_cast<Avatar*>(avatarIterator.value().data());
         
-        if (sharedAvatar == _myAvatar || !avatar->isInitialized()) {
+        if (avatar == _myAvatar || !avatar->isInitialized()) {
             // DO NOT update _myAvatar!  Its update has already been done earlier in the main loop.
-            // DO NOT update uninitialized Avatars
+            // DO NOT update or fade out uninitialized Avatars
             ++avatarIterator;
-            continue;
-        }
-        if (!shouldKillAvatar(sharedAvatar)) {
-            // this avatar's mixer is still around, go ahead and simulate it
+        } else if (avatar->shouldDie()) {
+            _avatarFades.push_back(avatarIterator.value());
+            avatarIterator = _avatarHash.erase(avatarIterator);
+        } else {
             avatar->simulate(deltaTime);
             ++avatarIterator;
-        } else {
-            // the mixer that owned this avatar is gone, give it to the vector of fades and kill it
-            avatarIterator = erase(avatarIterator);
         }
     }
     
@@ -175,24 +171,52 @@ AvatarSharedPointer AvatarManager::newSharedAvatar() {
     return AvatarSharedPointer(new Avatar());
 }
 
-AvatarHash::iterator AvatarManager::erase(const AvatarHash::iterator& iterator) {
-    if (iterator.key() != MY_AVATAR_KEY) {
-        if (reinterpret_cast<Avatar*>(iterator.value().data())->isInitialized()) {
-            _avatarFades.push_back(iterator.value());
+// virtual 
+AvatarSharedPointer AvatarManager::addAvatar(const QUuid& sessionUUID, const QWeakPointer<Node>& mixerWeakPointer) {
+    AvatarSharedPointer avatar = AvatarHashMap::addAvatar(sessionUUID, mixerWeakPointer);
+    return avatar;
+}
+
+// protected
+void AvatarManager::removeAvatarMotionState(Avatar* avatar) {
+    AvatarMotionState* motionState= avatar->_motionState;
+    if (motionState) {
+        // clean up physics stuff
+        motionState->clearObjectBackPointer();
+        avatar->_motionState = nullptr;
+        _avatarMotionStates.remove(motionState);
+        _motionStatesToAdd.remove(motionState);
+        _motionStatesToDelete.push_back(motionState);
+    }
+}
+
+// virtual 
+void AvatarManager::removeAvatar(const QUuid& sessionUUID) {
+    AvatarHash::iterator avatarIterator = _avatarHash.find(sessionUUID);
+    if (avatarIterator != _avatarHash.end()) {
+        Avatar* avatar = reinterpret_cast<Avatar*>(avatarIterator.value().data());
+        if (avatar != _myAvatar && avatar->isInitialized()) {
+            removeAvatarMotionState(avatar);
+
+            _avatarFades.push_back(avatarIterator.value());
+            _avatarHash.erase(avatarIterator);
         }
-        return AvatarHashMap::erase(iterator);
-    } else {
-        // never remove _myAvatar from the list
-        AvatarHash::iterator returnIterator = iterator;
-        return ++returnIterator;
     }
 }
 
 void AvatarManager::clearOtherAvatars() {
     // clear any avatars that came from an avatar-mixer
-    AvatarHash::iterator removeAvatar =  _avatarHash.begin();
-    while (removeAvatar != _avatarHash.end()) {
-        removeAvatar = erase(removeAvatar);
+    AvatarHash::iterator avatarIterator =  _avatarHash.begin();
+    while (avatarIterator != _avatarHash.end()) {
+        Avatar* avatar = reinterpret_cast<Avatar*>(avatarIterator.value().data());
+        if (avatar == _myAvatar || !avatar->isInitialized()) {
+            // don't remove myAvatar or uninitialized avatars from the list
+            ++avatarIterator;
+        } else {
+            removeAvatarMotionState(avatar);
+            _avatarFades.push_back(avatarIterator.value());
+            avatarIterator = _avatarHash.erase(avatarIterator);
+        }
     }
     _myAvatar->clearLookAtTargetAvatar();
 }
@@ -215,3 +239,57 @@ QVector<AvatarManager::LocalLight> AvatarManager::getLocalLights() const {
     return _localLights;
 }
 
+VectorOfMotionStates& AvatarManager::getObjectsToDelete() {
+    _tempMotionStates.clear();
+    _tempMotionStates.swap(_motionStatesToDelete);
+    return _tempMotionStates;
+}
+
+VectorOfMotionStates& AvatarManager::getObjectsToAdd() {
+    _tempMotionStates.clear();
+
+    for (auto motionState : _motionStatesToAdd) {
+        _tempMotionStates.push_back(motionState);
+    }
+    _motionStatesToAdd.clear();
+    return _tempMotionStates;
+}
+
+VectorOfMotionStates& AvatarManager::getObjectsToChange() {
+    _tempMotionStates.clear();
+    for (auto state : _avatarMotionStates) {
+        if (state->_dirtyFlags > 0) {
+            _tempMotionStates.push_back(state);
+        }
+    }
+    return _tempMotionStates;
+}
+
+void AvatarManager::handleOutgoingChanges(VectorOfMotionStates& motionStates) {
+    // TODO: extract the MyAvatar results once we use a MotionState for it.
+}
+
+void AvatarManager::handleCollisionEvents(CollisionEvents& collisionEvents) {
+    // TODO: expose avatar collision events to JS
+}
+
+void AvatarManager::updateAvatarPhysicsShape(const QUuid& id) {
+    AvatarHash::iterator avatarItr = _avatarHash.find(id);
+    if (avatarItr != _avatarHash.end()) {
+        Avatar* avatar = static_cast<Avatar*>(avatarItr.value().data());
+        AvatarMotionState* motionState = avatar->_motionState;
+        if (motionState) {
+            motionState->addDirtyFlags(EntityItem::DIRTY_SHAPE);
+        } else {
+            ShapeInfo shapeInfo;
+            avatar->computeShapeInfo(shapeInfo);
+            btCollisionShape* shape = ObjectMotionState::getShapeManager()->getShape(shapeInfo);
+            if (shape) {
+                AvatarMotionState* motionState = new AvatarMotionState(avatar, shape);
+                avatar->_motionState = motionState;
+                _motionStatesToAdd.insert(motionState);
+                _avatarMotionStates.insert(motionState);
+            }
+        }
+    }
+}
diff --git a/interface/src/avatar/AvatarManager.h b/interface/src/avatar/AvatarManager.h
index e6a358401c..bc4f7765d8 100644
--- a/interface/src/avatar/AvatarManager.h
+++ b/interface/src/avatar/AvatarManager.h
@@ -17,8 +17,10 @@
 #include <QtCore/QSharedPointer>
 
 #include <AvatarHashMap.h>
+#include <PhysicsEngine.h>
 
 #include "Avatar.h"
+#include "AvatarMotionState.h"
 
 class MyAvatar;
 
@@ -51,6 +53,14 @@ public:
     
     Q_INVOKABLE void setLocalLights(const QVector<AvatarManager::LocalLight>& localLights);
     Q_INVOKABLE QVector<AvatarManager::LocalLight> getLocalLights() const;
+
+    VectorOfMotionStates& getObjectsToDelete();
+    VectorOfMotionStates& getObjectsToAdd();
+    VectorOfMotionStates& getObjectsToChange();
+    void handleOutgoingChanges(VectorOfMotionStates& motionStates);
+    void handleCollisionEvents(CollisionEvents& collisionEvents);
+
+    void updateAvatarPhysicsShape(const QUuid& id);
    
 public slots:
     void setShouldShowReceiveStats(bool shouldShowReceiveStats) { _shouldShowReceiveStats = shouldShowReceiveStats; }
@@ -62,10 +72,11 @@ private:
     void simulateAvatarFades(float deltaTime);
     void renderAvatarFades(RenderArgs* renderArgs, const glm::vec3& cameraPosition);
     
-    AvatarSharedPointer newSharedAvatar();
-    
     // virtual overrides
-    AvatarHash::iterator erase(const AvatarHash::iterator& iterator);
+    virtual AvatarSharedPointer newSharedAvatar();
+    virtual AvatarSharedPointer addAvatar(const QUuid& sessionUUID, const QWeakPointer<Node>& mixerWeakPointer);
+    void removeAvatarMotionState(Avatar* avatar);
+    virtual void removeAvatar(const QUuid& sessionUUID);
     
     QVector<AvatarSharedPointer> _avatarFades;
     QSharedPointer<MyAvatar> _myAvatar;
@@ -74,6 +85,11 @@ private:
     QVector<AvatarManager::LocalLight> _localLights;
 
     bool _shouldShowReceiveStats = false;
+
+    SetOfAvatarMotionStates _avatarMotionStates;
+    SetOfMotionStates _motionStatesToAdd;
+    VectorOfMotionStates _motionStatesToDelete;
+    VectorOfMotionStates _tempMotionStates;
 };
 
 Q_DECLARE_METATYPE(AvatarManager::LocalLight)
diff --git a/interface/src/avatar/AvatarMotionState.cpp b/interface/src/avatar/AvatarMotionState.cpp
new file mode 100644
index 0000000000..03a49c069e
--- /dev/null
+++ b/interface/src/avatar/AvatarMotionState.cpp
@@ -0,0 +1,160 @@
+//
+//  AvatarMotionState.cpp
+//  interface/src/avatar/
+//
+//  Created by Andrew Meadows 2015.05.14
+//  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 <PhysicsHelpers.h>
+
+#include "Avatar.h"
+#include "AvatarMotionState.h"
+#include "BulletUtil.h"
+
+AvatarMotionState::AvatarMotionState(Avatar* avatar, btCollisionShape* shape) : ObjectMotionState(shape), _avatar(avatar) {
+    assert(_avatar);
+    if (_shape) {
+        _mass = 100.0f; // HACK
+    }
+}
+
+AvatarMotionState::~AvatarMotionState() {
+    _avatar = nullptr;
+}
+
+// virtual
+uint32_t AvatarMotionState::getAndClearIncomingDirtyFlags() {
+    uint32_t dirtyFlags = 0;
+    if (_body && _avatar) {
+        dirtyFlags = _dirtyFlags;
+        _dirtyFlags = 0;
+    }
+    return dirtyFlags;
+}
+
+MotionType AvatarMotionState::computeObjectMotionType() const {
+    // TODO?: support non-DYNAMIC motion for avatars? (e.g. when sitting)
+    return MOTION_TYPE_DYNAMIC;
+}
+
+// virtual and protected
+btCollisionShape* AvatarMotionState::computeNewShape() {
+    if (_avatar) {
+        ShapeInfo shapeInfo;
+        _avatar->computeShapeInfo(shapeInfo);
+        return getShapeManager()->getShape(shapeInfo);
+    }
+    return nullptr;
+}
+
+// virtual
+bool AvatarMotionState::isMoving() const {
+    return false;
+}
+
+// virtual
+void AvatarMotionState::getWorldTransform(btTransform& worldTrans) const {
+    if (!_avatar) {
+        return;
+    }
+    worldTrans.setOrigin(glmToBullet(getObjectPosition()));
+    worldTrans.setRotation(glmToBullet(getObjectRotation()));
+    if (_body) {
+        _body->setLinearVelocity(glmToBullet(getObjectLinearVelocity()));
+        _body->setAngularVelocity(glmToBullet(getObjectLinearVelocity()));
+    }
+}
+
+// virtual 
+void AvatarMotionState::setWorldTransform(const btTransform& worldTrans) {
+    if (!_avatar) {
+        return;
+    }
+    // HACK: The PhysicsEngine does not actually move OTHER avatars -- instead it slaves their local RigidBody to the transform
+    // as specified by a remote simulation.  However, to give the remote simulation time to respond to our own objects we tie
+    // the other avatar's body to its true position with a simple spring. This is a HACK that will have to be improved later.
+    const float SPRING_TIMESCALE = 0.5f;
+    float tau = PHYSICS_ENGINE_FIXED_SUBSTEP / SPRING_TIMESCALE;
+    btVector3 currentPosition = worldTrans.getOrigin();
+    btVector3 targetPosition = glmToBullet(getObjectPosition());
+    btTransform newTransform;
+    newTransform.setOrigin((1.0f - tau) * currentPosition + tau * targetPosition);
+    newTransform.setRotation(glmToBullet(getObjectRotation()));
+    _body->setWorldTransform(newTransform);
+    _body->setLinearVelocity(glmToBullet(getObjectLinearVelocity()));
+    _body->setAngularVelocity(glmToBullet(getObjectLinearVelocity()));
+}
+
+// These pure virtual methods must be implemented for each MotionState type
+// and make it possible to implement more complicated methods in this base class.
+
+// virtual
+float AvatarMotionState::getObjectRestitution() const {
+    return 0.5f;
+}
+
+// virtual
+float AvatarMotionState::getObjectFriction() const {
+    return 0.5f;
+}
+
+// virtual
+float AvatarMotionState::getObjectLinearDamping() const {
+    return 0.5f;
+}
+
+// virtual
+float AvatarMotionState::getObjectAngularDamping() const {
+    return 0.5f;
+}
+
+// virtual
+glm::vec3 AvatarMotionState::getObjectPosition() const {
+    return _avatar->getPosition();
+}
+
+// virtual
+glm::quat AvatarMotionState::getObjectRotation() const {
+    return _avatar->getOrientation();
+}
+
+// virtual
+const glm::vec3& AvatarMotionState::getObjectLinearVelocity() const {
+    return _avatar->getVelocity();
+}
+
+// virtual
+const glm::vec3& AvatarMotionState::getObjectAngularVelocity() const {
+    return _avatar->getAngularVelocity();
+}
+
+// virtual
+const glm::vec3& AvatarMotionState::getObjectGravity() const {
+    return _avatar->getAcceleration();
+}
+
+// virtual
+const QUuid& AvatarMotionState::getObjectID() const {
+    return _avatar->getSessionUUID();
+}
+
+// virtual
+QUuid AvatarMotionState::getSimulatorID() const {
+    return _avatar->getSessionUUID();
+}
+
+// virtual
+void AvatarMotionState::bump() {
+}
+
+// virtual 
+void AvatarMotionState::clearObjectBackPointer() {
+    ObjectMotionState::clearObjectBackPointer();
+    _avatar = nullptr;
+}
+
+
diff --git a/interface/src/avatar/AvatarMotionState.h b/interface/src/avatar/AvatarMotionState.h
new file mode 100644
index 0000000000..a4fc9db20a
--- /dev/null
+++ b/interface/src/avatar/AvatarMotionState.h
@@ -0,0 +1,75 @@
+//
+//  AvatarMotionState.h
+//  interface/src/avatar/
+//
+//  Created by Andrew Meadows 2015.05.14
+//  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_AvatarMotionState_h
+#define hifi_AvatarMotionState_h
+
+#include <QSet>
+
+#include <ObjectMotionState.h>
+
+class Avatar;
+
+class AvatarMotionState : public ObjectMotionState {
+public:
+    AvatarMotionState(Avatar* avatar, btCollisionShape* shape);
+    ~AvatarMotionState();
+
+    virtual MotionType getMotionType() const { return _motionType; }
+
+    virtual uint32_t getAndClearIncomingDirtyFlags();
+
+    virtual MotionType computeObjectMotionType() const;
+
+    virtual bool isMoving() const;
+
+    // this relays incoming position/rotation to the RigidBody
+    virtual void getWorldTransform(btTransform& worldTrans) const;
+
+    // this relays outgoing position/rotation to the EntityItem
+    virtual void setWorldTransform(const btTransform& worldTrans);
+
+
+    // These pure virtual methods must be implemented for each MotionState type
+    // and make it possible to implement more complicated methods in this base class.
+
+    virtual float getObjectRestitution() const;
+    virtual float getObjectFriction() const;
+    virtual float getObjectLinearDamping() const;
+    virtual float getObjectAngularDamping() const;
+    
+    virtual glm::vec3 getObjectPosition() const;
+    virtual glm::quat getObjectRotation() const;
+    virtual const glm::vec3& getObjectLinearVelocity() const;
+    virtual const glm::vec3& getObjectAngularVelocity() const;
+    virtual const glm::vec3& getObjectGravity() const;
+
+    virtual const QUuid& getObjectID() const;
+
+    virtual QUuid getSimulatorID() const;
+    virtual void bump();
+
+    void setBoundingBox(const glm::vec3& corner, const glm::vec3& diagonal);
+
+    void addDirtyFlags(uint32_t flags) { _dirtyFlags |= flags; }
+
+    friend class AvatarManager;
+
+protected:
+    virtual btCollisionShape* computeNewShape();
+    virtual void clearObjectBackPointer();
+    Avatar* _avatar;
+    uint32_t _dirtyFlags;
+};
+
+typedef QSet<AvatarMotionState*> SetOfAvatarMotionStates;
+
+#endif // hifi_AvatarMotionState_h
diff --git a/interface/src/avatar/SkeletonModel.cpp b/interface/src/avatar/SkeletonModel.cpp
index 8c52c79ca0..e2f4ca51a0 100644
--- a/interface/src/avatar/SkeletonModel.cpp
+++ b/interface/src/avatar/SkeletonModel.cpp
@@ -41,6 +41,7 @@ SkeletonModel::SkeletonModel(Avatar* owningAvatar, QObject* parent) :
     _headClipDistance(DEFAULT_NEAR_CLIP)
 {
     assert(_owningAvatar);
+    _enableShapes = true;
 }
 
 SkeletonModel::~SkeletonModel() {
diff --git a/libraries/avatars/src/AvatarData.h b/libraries/avatars/src/AvatarData.h
index 6a11f94cb6..603b5d76ea 100644
--- a/libraries/avatars/src/AvatarData.h
+++ b/libraries/avatars/src/AvatarData.h
@@ -69,6 +69,7 @@ const quint32 AVATAR_MOTION_DEFAULTS =
 const quint32 AVATAR_MOTION_SCRIPTABLE_BITS = 
         AVATAR_MOTION_SCRIPTED_MOTOR_ENABLED;
 
+const qint64 AVATAR_SILENCE_THRESHOLD_USECS = 5 * USECS_PER_SECOND;
 
 // Bitset of state flags - we store the key state, hand state, faceshift, chat circling, and existance of
 // referential data in this bit set. The hand state is an octal, but is split into two sections to maintain
@@ -290,7 +291,6 @@ public:
     QString getSkeletonModelURLFromScript() const { return _skeletonModelURL.toString(); }
     void setSkeletonModelURLFromScript(const QString& skeletonModelString) { setSkeletonModelURL(QUrl(skeletonModelString)); }
     
-    Node* getOwningAvatarMixer() { return _owningAvatarMixer.data(); }
     void setOwningAvatarMixer(const QWeakPointer<Node>& owningAvatarMixer) { _owningAvatarMixer = owningAvatarMixer; }
     
     const AABox& getLocalAABox() const { return _localAABox; }
@@ -301,8 +301,10 @@ public:
     int getReceiveRate() const;
 
     void setVelocity(const glm::vec3 velocity) { _velocity = velocity; }
-    Q_INVOKABLE glm::vec3 getVelocity() const { return _velocity; }
-    glm::vec3 getTargetVelocity() const { return _targetVelocity; }
+    Q_INVOKABLE const glm::vec3& getVelocity() const { return _velocity; }
+    const glm::vec3& getTargetVelocity() const { return _targetVelocity; }
+
+    bool shouldDie() const { return _owningAvatarMixer.isNull() || getUsecsSinceLastUpdate() > AVATAR_SILENCE_THRESHOLD_USECS; }
 
 public slots:
     void sendAvatarDataPacket();
diff --git a/libraries/avatars/src/AvatarHashMap.cpp b/libraries/avatars/src/AvatarHashMap.cpp
index b4291ef435..6d0d9d8d76 100644
--- a/libraries/avatars/src/AvatarHashMap.cpp
+++ b/libraries/avatars/src/AvatarHashMap.cpp
@@ -20,19 +20,6 @@ AvatarHashMap::AvatarHashMap() {
     connect(DependencyManager::get<NodeList>().data(), &NodeList::uuidChanged, this, &AvatarHashMap::sessionUUIDChanged);
 }
 
-
-AvatarHash::iterator AvatarHashMap::erase(const AvatarHash::iterator& iterator) {
-    qCDebug(avatars) << "Removing Avatar with UUID" << iterator.key() << "from AvatarHashMap.";
-    return _avatarHash.erase(iterator);
-}
-
-const qint64 AVATAR_SILENCE_THRESHOLD_USECS = 5 * USECS_PER_SECOND;
-
-bool AvatarHashMap::shouldKillAvatar(const AvatarSharedPointer& sharedAvatar) {
-    return (sharedAvatar->getOwningAvatarMixer() == NULL
-            || sharedAvatar->getUsecsSinceLastUpdate() > AVATAR_SILENCE_THRESHOLD_USECS);
-}
-
 void AvatarHashMap::processAvatarMixerDatagram(const QByteArray& datagram, const QWeakPointer<Node>& mixerWeakPointer) {
     switch (packetTypeForPacket(datagram)) {
         case PacketTypeBulkAvatarData:
@@ -52,10 +39,6 @@ void AvatarHashMap::processAvatarMixerDatagram(const QByteArray& datagram, const
     }
 }
 
-bool AvatarHashMap::containsAvatarWithDisplayName(const QString& displayName) {
-    return !avatarWithDisplayName(displayName).isNull();
-}
-
 bool AvatarHashMap::isAvatarInRange(const glm::vec3& position, const float range) {
     foreach(const AvatarSharedPointer& sharedAvatar, _avatarHash) {
         glm::vec3 avatarPosition = sharedAvatar->getPosition();
@@ -67,45 +50,19 @@ bool AvatarHashMap::isAvatarInRange(const glm::vec3& position, const float range
     return false;
 }
 
-AvatarWeakPointer AvatarHashMap::avatarWithDisplayName(const QString& displayName) {
-    foreach(const AvatarSharedPointer& sharedAvatar, _avatarHash) {
-        if (sharedAvatar->getDisplayName() == displayName) {
-            // this is a match
-            // check if this avatar should still be around
-            if (!shouldKillAvatar(sharedAvatar)) {
-                // we have a match, return the AvatarData
-                return sharedAvatar;
-            } else {
-                // we should remove this avatar, but we might not be on a thread that is allowed
-                // so we just return NULL to the caller
-                return AvatarWeakPointer();
-            }
-        }
-    }
-        
-    return AvatarWeakPointer();
-}
-
 AvatarSharedPointer AvatarHashMap::newSharedAvatar() {
     return AvatarSharedPointer(new AvatarData());
 }
 
-AvatarSharedPointer AvatarHashMap::matchingOrNewAvatar(const QUuid& sessionUUID, const QWeakPointer<Node>& mixerWeakPointer) {
-    AvatarSharedPointer matchingAvatar = _avatarHash.value(sessionUUID);
-    
-    if (!matchingAvatar) {
-        // insert the new avatar into our hash
-        matchingAvatar = newSharedAvatar();
-    
-        qCDebug(avatars) << "Adding avatar with sessionUUID " << sessionUUID << "to AvatarHashMap.";
-        
-        matchingAvatar->setSessionUUID(sessionUUID);
-        matchingAvatar->setOwningAvatarMixer(mixerWeakPointer);
-        
-        _avatarHash.insert(sessionUUID, matchingAvatar);
-    }
-    
-    return matchingAvatar;
+AvatarSharedPointer AvatarHashMap::addAvatar(const QUuid& sessionUUID, const QWeakPointer<Node>& mixerWeakPointer) {
+    qCDebug(avatars) << "Adding avatar with sessionUUID " << sessionUUID << "to AvatarHashMap.";
+
+    AvatarSharedPointer avatar = newSharedAvatar();
+    avatar->setSessionUUID(sessionUUID);
+    avatar->setOwningAvatarMixer(mixerWeakPointer);
+    _avatarHash.insert(sessionUUID, avatar);
+
+    return avatar;
 }
 
 void AvatarHashMap::processAvatarDataPacket(const QByteArray &datagram, const QWeakPointer<Node> &mixerWeakPointer) {
@@ -118,10 +75,13 @@ void AvatarHashMap::processAvatarDataPacket(const QByteArray &datagram, const QW
         bytesRead += NUM_BYTES_RFC4122_UUID;
         
         if (sessionUUID != _lastOwnerSessionUUID) {
-            AvatarSharedPointer matchingAvatarData = matchingOrNewAvatar(sessionUUID, mixerWeakPointer);
+            AvatarSharedPointer avatar = _avatarHash.value(sessionUUID);
+            if (!avatar) {
+                avatar = addAvatar(sessionUUID, mixerWeakPointer);
+            }
             
             // have the matching (or new) avatar parse the data from the packet
-            bytesRead += matchingAvatarData->parseDataAtOffset(datagram, bytesRead);
+            bytesRead += avatar->parseDataAtOffset(datagram, bytesRead);
         } else {
             // create a dummy AvatarData class to throw this data on the ground
             AvatarData dummyData;
@@ -145,24 +105,24 @@ void AvatarHashMap::processAvatarIdentityPacket(const QByteArray &packet, const
         identityStream >> sessionUUID >> faceMeshURL >> skeletonURL >> attachmentData >> displayName;
         
         // mesh URL for a UUID, find avatar in our list
-        AvatarSharedPointer matchingAvatar = matchingOrNewAvatar(sessionUUID, mixerWeakPointer);
-        if (matchingAvatar) {
-            
-            if (matchingAvatar->getFaceModelURL() != faceMeshURL) {
-                matchingAvatar->setFaceModelURL(faceMeshURL);
-            }
-            
-            if (matchingAvatar->getSkeletonModelURL() != skeletonURL) {
-                matchingAvatar->setSkeletonModelURL(skeletonURL);
-            }
-            
-            if (matchingAvatar->getAttachmentData() != attachmentData) {
-                matchingAvatar->setAttachmentData(attachmentData);
-            }
-            
-            if (matchingAvatar->getDisplayName() != displayName) {
-                matchingAvatar->setDisplayName(displayName);
-            }
+        AvatarSharedPointer avatar = _avatarHash.value(sessionUUID);
+        if (!avatar) {
+            avatar = addAvatar(sessionUUID, mixerWeakPointer);
+        }
+        if (avatar->getFaceModelURL() != faceMeshURL) {
+            avatar->setFaceModelURL(faceMeshURL);
+        }
+        
+        if (avatar->getSkeletonModelURL() != skeletonURL) {
+            avatar->setSkeletonModelURL(skeletonURL);
+        }
+        
+        if (avatar->getAttachmentData() != attachmentData) {
+            avatar->setAttachmentData(attachmentData);
+        }
+        
+        if (avatar->getDisplayName() != displayName) {
+            avatar->setDisplayName(displayName);
         }
     }
 }
@@ -171,24 +131,25 @@ void AvatarHashMap::processAvatarBillboardPacket(const QByteArray& packet, const
     int headerSize = numBytesForPacketHeader(packet);
     QUuid sessionUUID = QUuid::fromRfc4122(QByteArray::fromRawData(packet.constData() + headerSize, NUM_BYTES_RFC4122_UUID));
     
-    AvatarSharedPointer matchingAvatar = matchingOrNewAvatar(sessionUUID, mixerWeakPointer);
-    if (matchingAvatar) {
-        QByteArray billboard = packet.mid(headerSize + NUM_BYTES_RFC4122_UUID);
-        if (matchingAvatar->getBillboard() != billboard) {
-            matchingAvatar->setBillboard(billboard);
-        }
+    AvatarSharedPointer avatar = _avatarHash.value(sessionUUID);
+    if (!avatar) {
+        avatar = addAvatar(sessionUUID, mixerWeakPointer);
+    }
+
+    QByteArray billboard = packet.mid(headerSize + NUM_BYTES_RFC4122_UUID);
+    if (avatar->getBillboard() != billboard) {
+        avatar->setBillboard(billboard);
     }
 }
 
 void AvatarHashMap::processKillAvatar(const QByteArray& datagram) {
     // read the node id
     QUuid sessionUUID = QUuid::fromRfc4122(datagram.mid(numBytesForPacketHeader(datagram), NUM_BYTES_RFC4122_UUID));
-    
-    // remove the avatar with that UUID from our hash, if it exists
-    AvatarHash::iterator matchedAvatar = _avatarHash.find(sessionUUID);
-    if (matchedAvatar != _avatarHash.end()) {
-        erase(matchedAvatar);
-    }
+    removeAvatar(sessionUUID);
+}
+
+void AvatarHashMap::removeAvatar(const QUuid& sessionUUID) {
+    _avatarHash.remove(sessionUUID);
 }
 
 void AvatarHashMap::sessionUUIDChanged(const QUuid& sessionUUID, const QUuid& oldUUID) {
diff --git a/libraries/avatars/src/AvatarHashMap.h b/libraries/avatars/src/AvatarHashMap.h
index b7d40e2acc..9204826d03 100644
--- a/libraries/avatars/src/AvatarHashMap.h
+++ b/libraries/avatars/src/AvatarHashMap.h
@@ -36,28 +36,26 @@ public:
     
 public slots:
     void processAvatarMixerDatagram(const QByteArray& datagram, const QWeakPointer<Node>& mixerWeakPointer);
-    bool containsAvatarWithDisplayName(const QString& displayName);
     bool isAvatarInRange(const glm::vec3 & position, const float range);
-    AvatarWeakPointer avatarWithDisplayName(const QString& displayname);
     
 private slots:
     void sessionUUIDChanged(const QUuid& sessionUUID, const QUuid& oldUUID);
     
 protected:
     AvatarHashMap();
-    virtual AvatarHash::iterator erase(const AvatarHash::iterator& iterator);
-    
-    bool shouldKillAvatar(const AvatarSharedPointer& sharedAvatar);
     
     virtual AvatarSharedPointer newSharedAvatar();
-    AvatarSharedPointer matchingOrNewAvatar(const QUuid& nodeUUID, const QWeakPointer<Node>& mixerWeakPointer);
+    virtual AvatarSharedPointer addAvatar(const QUuid& sessionUUID, const QWeakPointer<Node>& mixerWeakPointer);
+    virtual void removeAvatar(const QUuid& sessionUUID);
     
+    AvatarHash _avatarHash;
+
+private:
     void processAvatarDataPacket(const QByteArray& packet, const QWeakPointer<Node>& mixerWeakPointer);
     void processAvatarIdentityPacket(const QByteArray& packet, const QWeakPointer<Node>& mixerWeakPointer);
     void processAvatarBillboardPacket(const QByteArray& packet, const QWeakPointer<Node>& mixerWeakPointer);
     void processKillAvatar(const QByteArray& datagram);
 
-    AvatarHash _avatarHash;
     QUuid _lastOwnerSessionUUID;
 };
 
diff --git a/libraries/entities-renderer/src/EntityTreeRenderer.cpp b/libraries/entities-renderer/src/EntityTreeRenderer.cpp
index 62b40e1698..500e76dc8d 100644
--- a/libraries/entities-renderer/src/EntityTreeRenderer.cpp
+++ b/libraries/entities-renderer/src/EntityTreeRenderer.cpp
@@ -537,7 +537,7 @@ const FBXGeometry* EntityTreeRenderer::getGeometryForEntity(EntityItemPointer en
     
     if (entityItem->getType() == EntityTypes::Model) {
         std::shared_ptr<RenderableModelEntityItem> modelEntityItem = 
-                                                            std::dynamic_pointer_cast<RenderableModelEntityItem>(entityItem);
+                                                        std::dynamic_pointer_cast<RenderableModelEntityItem>(entityItem);
         assert(modelEntityItem); // we need this!!!
         Model* model = modelEntityItem->getModel(this);
         if (model) {
@@ -551,7 +551,7 @@ const Model* EntityTreeRenderer::getModelForEntityItem(EntityItemPointer entityI
     const Model* result = NULL;
     if (entityItem->getType() == EntityTypes::Model) {
         std::shared_ptr<RenderableModelEntityItem> modelEntityItem = 
-                                                            std::dynamic_pointer_cast<RenderableModelEntityItem>(entityItem);
+                                                        std::dynamic_pointer_cast<RenderableModelEntityItem>(entityItem);
         result = modelEntityItem->getModel(this);
     }
     return result;
@@ -562,7 +562,7 @@ const FBXGeometry* EntityTreeRenderer::getCollisionGeometryForEntity(EntityItemP
     
     if (entityItem->getType() == EntityTypes::Model) {
         std::shared_ptr<RenderableModelEntityItem> modelEntityItem = 
-                                                            std::dynamic_pointer_cast<RenderableModelEntityItem>(entityItem);
+                                                        std::dynamic_pointer_cast<RenderableModelEntityItem>(entityItem);
         if (modelEntityItem->hasCompoundShapeURL()) {
             Model* model = modelEntityItem->getModel(this);
             if (model) {
diff --git a/libraries/entities-renderer/src/EntityTreeRenderer.h b/libraries/entities-renderer/src/EntityTreeRenderer.h
index 2693f1af02..711f021426 100644
--- a/libraries/entities-renderer/src/EntityTreeRenderer.h
+++ b/libraries/entities-renderer/src/EntityTreeRenderer.h
@@ -173,7 +173,6 @@ private:
 
     bool _hasPreviousZone = false;
     std::shared_ptr<ZoneEntityItem> _bestZone;
-
     float _bestZoneVolume;
 
     glm::vec3 _previousKeyLightColor;
diff --git a/libraries/entities-renderer/src/RenderableLineEntityItem.cpp b/libraries/entities-renderer/src/RenderableLineEntityItem.cpp
index d8d0496422..8981d149ae 100644
--- a/libraries/entities-renderer/src/RenderableLineEntityItem.cpp
+++ b/libraries/entities-renderer/src/RenderableLineEntityItem.cpp
@@ -29,7 +29,6 @@ void RenderableLineEntityItem::render(RenderArgs* args) {
     glm::vec3 p1 = ENTITY_ITEM_ZERO_VEC3;
     glm::vec3 p2 = getDimensions();
     glm::vec4 lineColor(toGlm(getXColor()), getLocalRenderAlpha());
-
     Q_ASSERT(args->_batch);
     gpu::Batch& batch = *args->_batch;
     batch.setModelTransform(getTransformToCenter());
diff --git a/libraries/model/src/model/Geometry.cpp b/libraries/model/src/model/Geometry.cpp
index 156f593421..ed0201763a 100755
--- a/libraries/model/src/model/Geometry.cpp
+++ b/libraries/model/src/model/Geometry.cpp
@@ -43,18 +43,18 @@ void Mesh::addAttribute(Slot slot, const BufferView& buffer) {
 }
 
 void Mesh::evalVertexFormat() {
-    VertexFormat vf;
+    auto vf = new VertexFormat();
     int channelNum = 0;
     if (hasVertexData()) {
-        vf.setAttribute(gpu::Stream::POSITION, channelNum, _vertexBuffer._element, 0);
+        vf->setAttribute(gpu::Stream::POSITION, channelNum, _vertexBuffer._element, 0);
         channelNum++;
     }
     for (auto attrib : _attributeBuffers) {
-        vf.setAttribute(attrib.first, channelNum, attrib.second._element, 0);
+        vf->setAttribute(attrib.first, channelNum, attrib.second._element, 0);
         channelNum++;
     }
 
-    _vertexFormat = vf;
+    _vertexFormat.reset(vf);
 }
 
 void Mesh::setIndexBuffer(const BufferView& buffer) {
@@ -112,12 +112,12 @@ const gpu::BufferStream Mesh::makeBufferStream() const {
 
     int channelNum = 0;
     if (hasVertexData()) {
-        stream.addBuffer(_vertexBuffer._buffer, _vertexBuffer._offset, _vertexFormat.getChannelStride(channelNum));
+        stream.addBuffer(_vertexBuffer._buffer, _vertexBuffer._offset, _vertexFormat->getChannelStride(channelNum));
         channelNum++;
     }
     for (auto attrib : _attributeBuffers) {
         BufferView& view = attrib.second;
-        stream.addBuffer(view._buffer, view._offset, _vertexFormat.getChannelStride(channelNum));
+        stream.addBuffer(view._buffer, view._offset, _vertexFormat->getChannelStride(channelNum));
         channelNum++;
     }
 
diff --git a/libraries/model/src/model/Geometry.h b/libraries/model/src/model/Geometry.h
index 31c06e6eca..95f1c3bce7 100755
--- a/libraries/model/src/model/Geometry.h
+++ b/libraries/model/src/model/Geometry.h
@@ -47,14 +47,14 @@ public:
     void setVertexBuffer(const BufferView& buffer);
     const BufferView& getVertexBuffer() const { return _vertexBuffer; }
     uint getNumVertices() const { return _vertexBuffer.getNumElements(); }
-    bool hasVertexData() const { return !_vertexBuffer._buffer; }
+    bool hasVertexData() const { return _vertexBuffer._buffer.get() != nullptr; }
 
     // Attribute Buffers
     int getNumAttributes() const { return _attributeBuffers.size(); }
     void addAttribute(Slot slot, const BufferView& buffer);
 
     // Stream format
-    const VertexFormat& getVertexFormat() const { return _vertexFormat; }
+    const gpu::Stream::FormatPointer getVertexFormat() const { return _vertexFormat; }
 
     // Index Buffer
     void setIndexBuffer(const BufferView& buffer);
@@ -114,7 +114,7 @@ public:
 
 protected:
 
-    VertexFormat _vertexFormat;
+    gpu::Stream::FormatPointer _vertexFormat;
 
     BufferView _vertexBuffer;
     BufferViewMap _attributeBuffers;
diff --git a/libraries/networking/src/ReceivedPacketProcessor.cpp b/libraries/networking/src/ReceivedPacketProcessor.cpp
index db4c97f8d6..894a7b8aa9 100644
--- a/libraries/networking/src/ReceivedPacketProcessor.cpp
+++ b/libraries/networking/src/ReceivedPacketProcessor.cpp
@@ -27,7 +27,7 @@ void ReceivedPacketProcessor::queueReceivedPacket(const SharedNodePointer& sendi
     _nodePacketCounts[sendingNode->getUUID()]++;
     unlock();
     
-    // Make sure to  wake our actual processing thread because we  now have packets for it to process.
+    // Make sure to wake our actual processing thread because we now have packets for it to process.
     _hasPackets.wakeAll();
 }
 
diff --git a/libraries/octree/src/OctreeConstants.h b/libraries/octree/src/OctreeConstants.h
index 1246aeffd4..4a1baea2d5 100644
--- a/libraries/octree/src/OctreeConstants.h
+++ b/libraries/octree/src/OctreeConstants.h
@@ -34,9 +34,9 @@ const float VIEW_FRUSTUM_FOV_OVERSEND = 60.0f;
 // These are guards to prevent our voxel tree recursive routines from spinning out of control
 const int UNREASONABLY_DEEP_RECURSION = 29; // use this for something that you want to be shallow, but not spin out
 const int DANGEROUSLY_DEEP_RECURSION = 200; // use this for something that needs to go deeper
-const float SCALE_AT_UNREASONABLY_DEEP_RECURSION = (1.0f / powf(2.0f, UNREASONABLY_DEEP_RECURSION));
-const float SCALE_AT_DANGEROUSLY_DEEP_RECURSION = (1.0f / powf(2.0f, DANGEROUSLY_DEEP_RECURSION));
-const float SMALLEST_REASONABLE_OCTREE_ELEMENT_SCALE = SCALE_AT_UNREASONABLY_DEEP_RECURSION * 2.0f; // 0.00006103515 meter ~1/10,0000th
+const float SCALE_AT_UNREASONABLY_DEEP_RECURSION = (TREE_SCALE / powf(2.0f, UNREASONABLY_DEEP_RECURSION));
+const float SCALE_AT_DANGEROUSLY_DEEP_RECURSION = (TREE_SCALE / powf(2.0f, DANGEROUSLY_DEEP_RECURSION));
+const float SMALLEST_REASONABLE_OCTREE_ELEMENT_SCALE = SCALE_AT_UNREASONABLY_DEEP_RECURSION * 2.0f; // 0.00001525878 meter ~1/10,0000th
 
 const int DEFAULT_MAX_OCTREE_PPS = 600; // the default maximum PPS we think any octree based server should send to a client
 
diff --git a/libraries/physics/src/DynamicCharacterController.cpp b/libraries/physics/src/DynamicCharacterController.cpp
index eebd8f0c88..5d2a1798f9 100644
--- a/libraries/physics/src/DynamicCharacterController.cpp
+++ b/libraries/physics/src/DynamicCharacterController.cpp
@@ -311,9 +311,11 @@ void DynamicCharacterController::updateShapeIfNecessary() {
             // create new shape
             _shape = new btCapsuleShape(_radius, 2.0f * _halfHeight);
 
+            // HACK: use some simple mass property defaults for now
+            float mass = 100.0f;
+            btVector3 inertia(30.0f, 8.0f, 30.0f);
+
             // create new body
-            float mass = 1.0f;
-            btVector3 inertia(1.0f, 1.0f, 1.0f);
             _rigidBody = new btRigidBody(mass, nullptr, _shape, inertia);
             _rigidBody->setSleepingThresholds(0.0f, 0.0f);
             _rigidBody->setAngularFactor(0.0f);
diff --git a/libraries/physics/src/EntityMotionState.cpp b/libraries/physics/src/EntityMotionState.cpp
index 12a6ef03ff..6c4b3dad75 100644
--- a/libraries/physics/src/EntityMotionState.cpp
+++ b/libraries/physics/src/EntityMotionState.cpp
@@ -39,8 +39,9 @@ EntityMotionState::EntityMotionState(btCollisionShape* shape, EntityItemPointer
     _loopsSinceOwnershipBid(0),
     _loopsWithoutOwner(0)
 {
-    _type = MOTION_STATE_TYPE_ENTITY;
-    assert(entity != nullptr);
+    _type = MOTIONSTATE_TYPE_ENTITY;
+    assert(_entity != nullptr);
+    setMass(_entity->computeMass());
 }
 
 EntityMotionState::~EntityMotionState() {
@@ -88,7 +89,6 @@ void EntityMotionState::handleEasyChanges(uint32_t flags) {
     if ((flags & EntityItem::DIRTY_PHYSICS_ACTIVATION) && !_body->isActive()) {
         _body->activate();
     }
-
 }
 
 
@@ -98,10 +98,9 @@ void EntityMotionState::handleHardAndEasyChanges(uint32_t flags, PhysicsEngine*
     ObjectMotionState::handleHardAndEasyChanges(flags, engine);
 }
 
-void EntityMotionState::clearEntity() {
+void EntityMotionState::clearObjectBackPointer() {
+    ObjectMotionState::clearObjectBackPointer();
     _entity = nullptr;
-    // set the type to INVALID so that external logic that pivots on the type won't try to access _entity
-    _type = MOTION_STATE_TYPE_INVALID;
 }
 
 MotionType EntityMotionState::computeObjectMotionType() const {
@@ -178,10 +177,14 @@ void EntityMotionState::setWorldTransform(const btTransform& worldTrans) {
     #endif
 }
 
-void EntityMotionState::computeObjectShapeInfo(ShapeInfo& shapeInfo) {
+// virtual and protected
+btCollisionShape* EntityMotionState::computeNewShape() {
     if (_entity) {
+        ShapeInfo shapeInfo;
         _entity->computeShapeInfo(shapeInfo);
+        return getShapeManager()->getShape(shapeInfo);
     }
+    return nullptr;
 }
 
 // RELIABLE_SEND_HACK: until we have truly reliable resends of non-moving updates
@@ -444,7 +447,7 @@ void EntityMotionState::sendUpdate(OctreeEditPacketSender* packetSender, const Q
     _lastStep = step;
 }
 
-uint32_t EntityMotionState::getAndClearIncomingDirtyFlags() const { 
+uint32_t EntityMotionState::getAndClearIncomingDirtyFlags() { 
     uint32_t dirtyFlags = 0;
     if (_body && _entity) {
         dirtyFlags = _entity->getDirtyFlags(); 
diff --git a/libraries/physics/src/EntityMotionState.h b/libraries/physics/src/EntityMotionState.h
index f359ec7fee..80b56ccf2a 100644
--- a/libraries/physics/src/EntityMotionState.h
+++ b/libraries/physics/src/EntityMotionState.h
@@ -43,14 +43,12 @@ public:
     // this relays outgoing position/rotation to the EntityItem
     virtual void setWorldTransform(const btTransform& worldTrans);
 
-    virtual void computeObjectShapeInfo(ShapeInfo& shapeInfo);
-
     bool isCandidateForOwnership(const QUuid& sessionID) const;
     bool remoteSimulationOutOfSync(uint32_t simulationStep);
     bool shouldSendUpdate(uint32_t simulationStep, const QUuid& sessionID);
     void sendUpdate(OctreeEditPacketSender* packetSender, const QUuid& sessionID, uint32_t step);
 
-    virtual uint32_t getAndClearIncomingDirtyFlags() const;
+    virtual uint32_t getAndClearIncomingDirtyFlags();
 
     void incrementAccelerationNearlyGravityCount() { _accelerationNearlyGravityCount++; }
     void resetAccelerationNearlyGravityCount() { _accelerationNearlyGravityCount = 0; }
@@ -62,7 +60,7 @@ public:
     virtual float getObjectAngularDamping() const { return _entity->getAngularDamping(); }
 
     virtual glm::vec3 getObjectPosition() const { return _entity->getPosition() - ObjectMotionState::getWorldOffset(); }
-    virtual const glm::quat& getObjectRotation() const { return _entity->getRotation(); }
+    virtual glm::quat getObjectRotation() const { return _entity->getRotation(); }
     virtual const glm::vec3& getObjectLinearVelocity() const { return _entity->getVelocity(); }
     virtual const glm::vec3& getObjectAngularVelocity() const { return _entity->getAngularVelocity(); }
     virtual const glm::vec3& getObjectGravity() const { return _entity->getGravity(); }
@@ -82,8 +80,8 @@ public:
     friend class PhysicalEntitySimulation;
 
 protected:
-    void clearEntity();
-
+    virtual btCollisionShape* computeNewShape();
+    virtual void clearObjectBackPointer();
     virtual void setMotionType(MotionType motionType);
 
     EntityItemPointer _entity;
diff --git a/libraries/physics/src/ObjectMotionState.cpp b/libraries/physics/src/ObjectMotionState.cpp
index c5288cfa76..57b75f0f3b 100644
--- a/libraries/physics/src/ObjectMotionState.cpp
+++ b/libraries/physics/src/ObjectMotionState.cpp
@@ -140,20 +140,14 @@ void ObjectMotionState::handleEasyChanges(uint32_t flags) {
     }
 
     if (flags & EntityItem::DIRTY_MASS) {
-        float mass = getMass();
-        btVector3 inertia(0.0f, 0.0f, 0.0f);
-        _body->getCollisionShape()->calculateLocalInertia(mass, inertia);
-        _body->setMassProps(mass, inertia);
-        _body->updateInertiaTensor();
+        updateBodyMassProperties();
     }
 }
 
 void ObjectMotionState::handleHardAndEasyChanges(uint32_t flags, PhysicsEngine* engine) {
     if (flags & EntityItem::DIRTY_SHAPE) {
         // make sure the new shape is valid
-        ShapeInfo shapeInfo;
-        computeObjectShapeInfo(shapeInfo);
-        btCollisionShape* newShape = getShapeManager()->getShape(shapeInfo);
+        btCollisionShape* newShape = computeNewShape();
         if (!newShape) {
             qCDebug(physics) << "Warning: failed to generate new shape!";
             // failed to generate new shape! --> keep old shape and remove shape-change flag
@@ -168,17 +162,22 @@ void ObjectMotionState::handleHardAndEasyChanges(uint32_t flags, PhysicsEngine*
             }
         }
         getShapeManager()->releaseShape(_shape);
-        _shape = newShape;
-        _body->setCollisionShape(_shape);
-        if (flags & EASY_DIRTY_PHYSICS_FLAGS) {
-            handleEasyChanges(flags);
-        }
-    } else {
-        if (flags & EASY_DIRTY_PHYSICS_FLAGS) {
-            handleEasyChanges(flags);
+        if (_shape != newShape) {
+            _shape = newShape;
+            _body->setCollisionShape(_shape);
+        } else {
+            // huh... the shape didn't actually change, so we clear the DIRTY_SHAPE flag
+            flags &= ~EntityItem::DIRTY_SHAPE;
         }
     }
-    engine->reinsertObject(this);
+    if (flags & EASY_DIRTY_PHYSICS_FLAGS) {
+        handleEasyChanges(flags);
+    }
+    // it is possible that there are no HARD flags at this point (if DIRTY_SHAPE was removed)
+    // so we check again befoe we reinsert:
+    if (flags & HARD_DIRTY_PHYSICS_FLAGS) {
+        engine->reinsertObject(this);
+    }
 }
 
 void ObjectMotionState::updateBodyMaterialProperties() {
@@ -193,3 +192,11 @@ void ObjectMotionState::updateBodyVelocities() {
     setBodyGravity(getObjectGravity());
     _body->setActivationState(ACTIVE_TAG);
 }
+
+void ObjectMotionState::updateBodyMassProperties() {
+    float mass = getMass();
+    btVector3 inertia(0.0f, 0.0f, 0.0f);
+    _body->getCollisionShape()->calculateLocalInertia(mass, inertia);
+    _body->setMassProps(mass, inertia);
+    _body->updateInertiaTensor();
+}
diff --git a/libraries/physics/src/ObjectMotionState.h b/libraries/physics/src/ObjectMotionState.h
index bfc9310ec6..337f09e719 100644
--- a/libraries/physics/src/ObjectMotionState.h
+++ b/libraries/physics/src/ObjectMotionState.h
@@ -15,6 +15,9 @@
 #include <btBulletDynamicsCommon.h>
 #include <glm/glm.hpp>
 
+#include <QSet>
+#include <QVector>
+
 #include <EntityItem.h>
 
 #include "ContactInfo.h"
@@ -27,9 +30,9 @@ enum MotionType {
 };
 
 enum MotionStateType {
-    MOTION_STATE_TYPE_INVALID,
-    MOTION_STATE_TYPE_ENTITY,
-    MOTION_STATE_TYPE_AVATAR
+    MOTIONSTATE_TYPE_INVALID,
+    MOTIONSTATE_TYPE_ENTITY,
+    MOTIONSTATE_TYPE_AVATAR
 };
 
 // The update flags trigger two varieties of updates: "hard" which require the body to be pulled 
@@ -71,8 +74,9 @@ public:
     virtual void handleEasyChanges(uint32_t flags);
     virtual void handleHardAndEasyChanges(uint32_t flags, PhysicsEngine* engine);
 
-    virtual void updateBodyMaterialProperties();
-    virtual void updateBodyVelocities();
+    void updateBodyMaterialProperties();
+    void updateBodyVelocities();
+    virtual void updateBodyMassProperties();
 
     MotionStateType getType() const { return _type; }
     virtual MotionType getMotionType() const { return _motionType; }
@@ -87,11 +91,9 @@ public:
     glm::vec3 getBodyLinearVelocity() const;
     glm::vec3 getBodyAngularVelocity() const;
 
-    virtual uint32_t getAndClearIncomingDirtyFlags() const = 0;
+    virtual uint32_t getAndClearIncomingDirtyFlags() = 0;
 
     virtual MotionType computeObjectMotionType() const = 0;
-    virtual void computeObjectShapeInfo(ShapeInfo& shapeInfo) = 0;
-
 
     btCollisionShape* getShape() const { return _shape; }
     btRigidBody* getRigidBody() const { return _body; }
@@ -109,7 +111,7 @@ public:
     virtual float getObjectAngularDamping() const = 0;
     
     virtual glm::vec3 getObjectPosition() const = 0;
-    virtual const glm::quat& getObjectRotation() const = 0;
+    virtual glm::quat getObjectRotation() const = 0;
     virtual const glm::vec3& getObjectLinearVelocity() const = 0;
     virtual const glm::vec3& getObjectAngularVelocity() const = 0;
     virtual const glm::vec3& getObjectGravity() const = 0;
@@ -124,10 +126,15 @@ public:
     friend class PhysicsEngine;
 
 protected:
-    virtual void setMotionType(MotionType motionType);
+    virtual btCollisionShape* computeNewShape() = 0;
+    void setMotionType(MotionType motionType);
+
+    // clearObjectBackPointer() overrrides should call the base method, then actually clear the object back pointer.
+    virtual void clearObjectBackPointer() { _type = MOTIONSTATE_TYPE_INVALID; }
+
     void setRigidBody(btRigidBody* body);
 
-    MotionStateType _type = MOTION_STATE_TYPE_INVALID; // type of MotionState
+    MotionStateType _type = MOTIONSTATE_TYPE_INVALID; // type of MotionState
     MotionType _motionType; // type of motion: KINEMATIC, DYNAMIC, or STATIC
 
     btCollisionShape* _shape;
@@ -137,4 +144,7 @@ protected:
     uint32_t _lastKinematicStep;
 };
 
+typedef QSet<ObjectMotionState*> SetOfMotionStates;
+typedef QVector<ObjectMotionState*> VectorOfMotionStates;
+
 #endif // hifi_ObjectMotionState_h
diff --git a/libraries/physics/src/PhysicalEntitySimulation.cpp b/libraries/physics/src/PhysicalEntitySimulation.cpp
index 54a3048bed..b615cf0c77 100644
--- a/libraries/physics/src/PhysicalEntitySimulation.cpp
+++ b/libraries/physics/src/PhysicalEntitySimulation.cpp
@@ -9,11 +9,9 @@
 //  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
 //
 
-#include "EntityMotionState.h"
 #include "PhysicalEntitySimulation.h"
 #include "PhysicsHelpers.h"
 #include "PhysicsLogging.h"
-#include "ShapeInfoUtil.h"
 #include "ShapeManager.h"
 
 PhysicalEntitySimulation::PhysicalEntitySimulation() {
@@ -25,7 +23,6 @@ PhysicalEntitySimulation::~PhysicalEntitySimulation() {
 void PhysicalEntitySimulation::init(
         EntityTree* tree,
         PhysicsEngine* physicsEngine,
-        ShapeManager* shapeManager,
         EntityEditPacketSender* packetSender) {
     assert(tree);
     setEntityTree(tree);
@@ -33,9 +30,6 @@ void PhysicalEntitySimulation::init(
     assert(physicsEngine);
     _physicsEngine = physicsEngine;
 
-    assert(shapeManager);
-    _shapeManager = shapeManager;
-
     assert(packetSender);
     _entityPacketSender = packetSender;
 }
@@ -60,7 +54,7 @@ void PhysicalEntitySimulation::addEntityInternal(EntityItemPointer entity) {
 void PhysicalEntitySimulation::removeEntityInternal(EntityItemPointer entity) {
     EntityMotionState* motionState = static_cast<EntityMotionState*>(entity->getPhysicsInfo());
     if (motionState) {
-        motionState->clearEntity();
+        motionState->clearObjectBackPointer();
         entity->setPhysicsInfo(nullptr);
         _pendingRemoves.insert(motionState);
         _outgoingChanges.remove(motionState);
@@ -109,7 +103,7 @@ void PhysicalEntitySimulation::clearEntitiesInternal() {
         if (entity) {
             entity->setPhysicsInfo(nullptr);
         }
-        motionState->clearEntity();
+        motionState->clearObjectBackPointer();
     }
 
     // then delete the objects (aka MotionStates)
@@ -135,7 +129,7 @@ VectorOfMotionStates& PhysicalEntitySimulation::getObjectsToDelete() {
         if (entity) {
             _pendingAdds.remove(entity);
             entity->setPhysicsInfo(nullptr);
-            motionState->clearEntity();
+            motionState->clearObjectBackPointer();
         }
         _tempVector.push_back(motionState);
     }
@@ -158,16 +152,14 @@ VectorOfMotionStates& PhysicalEntitySimulation::getObjectsToAdd() {
         } else if (entity->isReadyToComputeShape()) {
             ShapeInfo shapeInfo;
             entity->computeShapeInfo(shapeInfo);
-            btCollisionShape* shape = _shapeManager->getShape(shapeInfo);
+            btCollisionShape* shape = ObjectMotionState::getShapeManager()->getShape(shapeInfo);
             if (shape) {
                 EntityMotionState* motionState = new EntityMotionState(shape, entity);
                 entity->setPhysicsInfo(static_cast<void*>(motionState));
-                motionState->setMass(entity->computeMass());
                 _physicalObjects.insert(motionState);
                 _tempVector.push_back(motionState);
                 entityItr = _pendingAdds.erase(entityItr);
             } else {
-                // TODO: Seth to look into why this case is hit.
                 //qDebug() << "Warning!  Failed to generate new shape for entity." << entity->getName();
                 ++entityItr;
             }
@@ -192,7 +184,7 @@ void PhysicalEntitySimulation::handleOutgoingChanges(VectorOfMotionStates& motio
     // walk the motionStates looking for those that correspond to entities
     for (auto stateItr : motionStates) {
         ObjectMotionState* state = &(*stateItr);
-        if (state && state->getType() == MOTION_STATE_TYPE_ENTITY) {
+        if (state && state->getType() == MOTIONSTATE_TYPE_ENTITY) {
             EntityMotionState* entityState = static_cast<EntityMotionState*>(state);
             EntityItemPointer entity = entityState->getEntity();
             if (entity) {
diff --git a/libraries/physics/src/PhysicalEntitySimulation.h b/libraries/physics/src/PhysicalEntitySimulation.h
index 8b3259dbae..1aae27962a 100644
--- a/libraries/physics/src/PhysicalEntitySimulation.h
+++ b/libraries/physics/src/PhysicalEntitySimulation.h
@@ -21,10 +21,7 @@
 #include <EntitySimulation.h>
 
 #include "PhysicsEngine.h"
-#include "PhysicsTypedefs.h"
-
-class EntityMotionState;
-class ShapeManager;
+#include "EntityMotionState.h"
 
 typedef QSet<EntityMotionState*> SetOfEntityMotionStates;
 
@@ -33,7 +30,7 @@ public:
     PhysicalEntitySimulation();
     ~PhysicalEntitySimulation();
 
-    void init(EntityTree* tree, PhysicsEngine* engine, ShapeManager* shapeManager, EntityEditPacketSender* packetSender);
+    void init(EntityTree* tree, PhysicsEngine* engine, EntityEditPacketSender* packetSender);
 
 protected: // only called by EntitySimulation
     // overrides for EntitySimulation
@@ -63,7 +60,6 @@ private:
     SetOfMotionStates _physicalObjects; // MotionStates of entities in PhysicsEngine
     VectorOfMotionStates _tempVector; // temporary array reference, valid immediately after getObjectsToRemove() (and friends)
 
-    ShapeManager* _shapeManager = nullptr;
     PhysicsEngine* _physicsEngine = nullptr;
     EntityEditPacketSender* _entityPacketSender = nullptr;
 
diff --git a/libraries/physics/src/PhysicsEngine.cpp b/libraries/physics/src/PhysicsEngine.cpp
index bfd0b6cb28..b622a37136 100644
--- a/libraries/physics/src/PhysicsEngine.cpp
+++ b/libraries/physics/src/PhysicsEngine.cpp
@@ -318,16 +318,16 @@ CollisionEvents& PhysicsEngine::getCollisionEvents() {
             ObjectMotionState* A = static_cast<ObjectMotionState*>(contactItr->first._a);
             ObjectMotionState* B = static_cast<ObjectMotionState*>(contactItr->first._b);
 
-            if (A && A->getType() == MOTION_STATE_TYPE_ENTITY) {
+            if (A && A->getType() == MOTIONSTATE_TYPE_ENTITY) {
                 QUuid idA = A->getObjectID();
                 QUuid idB;
-                if (B && B->getType() == MOTION_STATE_TYPE_ENTITY) {
+                if (B && B->getType() == MOTIONSTATE_TYPE_ENTITY) {
                     idB = B->getObjectID();
                 }
                 glm::vec3 position = bulletToGLM(contact.getPositionWorldOnB()) + _originOffset;
                 glm::vec3 penetration = bulletToGLM(contact.distance * contact.normalWorldOnB);
                 _collisionEvents.push_back(Collision(type, idA, idB, position, penetration));
-            } else if (B && B->getType() == MOTION_STATE_TYPE_ENTITY) {
+            } else if (B && B->getType() == MOTIONSTATE_TYPE_ENTITY) {
                 QUuid idB = B->getObjectID();
                 glm::vec3 position = bulletToGLM(contact.getPositionWorldOnA()) + _originOffset;
                 // NOTE: we're flipping the order of A and B (so that the first objectID is never NULL) 
diff --git a/libraries/physics/src/PhysicsEngine.h b/libraries/physics/src/PhysicsEngine.h
index d1dc5bcd79..9ff85c9f11 100644
--- a/libraries/physics/src/PhysicsEngine.h
+++ b/libraries/physics/src/PhysicsEngine.h
@@ -22,13 +22,11 @@
 #include "BulletUtil.h"
 #include "ContactInfo.h"
 #include "DynamicCharacterController.h"
-#include "PhysicsTypedefs.h"
+#include "ObjectMotionState.h"
 #include "ThreadSafeDynamicsWorld.h"
 
 const float HALF_SIMULATION_EXTENT = 512.0f; // meters
 
-class ObjectMotionState;
-
 // simple class for keeping track of contacts
 class ContactKey {
 public:
diff --git a/libraries/physics/src/PhysicsTypedefs.h b/libraries/physics/src/PhysicsTypedefs.h
deleted file mode 100644
index 9d9685a758..0000000000
--- a/libraries/physics/src/PhysicsTypedefs.h
+++ /dev/null
@@ -1,23 +0,0 @@
-//
-//  PhysicsTypedefs.h
-//  libraries/physcis/src
-//
-//  Created by Andrew Meadows 2015.04.29
-//  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_PhysicsTypedefs_h
-#define hifi_PhysicsTypedefs_h
-
-#include <QSet>
-#include <QVector>
-
-class ObjectMotionState;
-
-typedef QSet<ObjectMotionState*> SetOfMotionStates;
-typedef QVector<ObjectMotionState*> VectorOfMotionStates;
-
-#endif //hifi_PhysicsTypedefs_h
diff --git a/libraries/physics/src/ShapeInfoUtil.cpp b/libraries/physics/src/ShapeFactory.cpp
similarity index 81%
rename from libraries/physics/src/ShapeInfoUtil.cpp
rename to libraries/physics/src/ShapeFactory.cpp
index 1cccd691c2..74b0304ace 100644
--- a/libraries/physics/src/ShapeInfoUtil.cpp
+++ b/libraries/physics/src/ShapeFactory.cpp
@@ -1,5 +1,5 @@
 //
-//  ShapeInfoUtil.cpp
+//  ShapeFactory.cpp
 //  libraries/physcis/src
 //
 //  Created by Andrew Meadows 2014.12.01
@@ -9,14 +9,16 @@
 //  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
 //
 
+#include <glm/gtx/norm.hpp>
+
 #include <SharedUtil.h> // for MILLIMETERS_PER_METER
 
-#include "ShapeInfoUtil.h"
+#include "ShapeFactory.h"
 #include "BulletUtil.h"
 
 
 
-btConvexHullShape* ShapeInfoUtil::createConvexHull(const QVector<glm::vec3>& points) {
+btConvexHullShape* ShapeFactory::createConvexHull(const QVector<glm::vec3>& points) {
     assert(points.size() > 0);
 
     btConvexHullShape* hull = new btConvexHullShape();
@@ -57,9 +59,10 @@ btConvexHullShape* ShapeInfoUtil::createConvexHull(const QVector<glm::vec3>& poi
     return hull;
 }
 
-btCollisionShape* ShapeInfoUtil::createShapeFromInfo(const ShapeInfo& info) {
+btCollisionShape* ShapeFactory::createShapeFromInfo(const ShapeInfo& info) {
     btCollisionShape* shape = NULL;
-    switch(info.getType()) {
+    int type = info.getType();
+    switch(type) {
         case SHAPE_TYPE_BOX: {
             shape = new btBoxShape(glmToBullet(info.getHalfExtents()));
         }
@@ -95,5 +98,17 @@ btCollisionShape* ShapeInfoUtil::createShapeFromInfo(const ShapeInfo& info) {
         }
         break;
     }
+    if (shape && type != SHAPE_TYPE_COMPOUND) {
+        if (glm::length2(info.getOffset()) > MIN_SHAPE_OFFSET * MIN_SHAPE_OFFSET) {
+            // this shape has an offset, which we support by wrapping the true shape
+            // in a btCompoundShape with a local transform
+            auto compound = new btCompoundShape(); 
+            btTransform trans;
+            trans.setIdentity();
+            trans.setOrigin(glmToBullet(info.getOffset()));
+            compound->addChildShape(trans, shape);
+            shape = compound;
+        }
+    }
     return shape;
 }
diff --git a/libraries/physics/src/ShapeInfoUtil.h b/libraries/physics/src/ShapeFactory.h
similarity index 81%
rename from libraries/physics/src/ShapeInfoUtil.h
rename to libraries/physics/src/ShapeFactory.h
index 7284cd3550..699b8a0475 100644
--- a/libraries/physics/src/ShapeInfoUtil.h
+++ b/libraries/physics/src/ShapeFactory.h
@@ -1,5 +1,5 @@
 //
-//  ShapeInfoUtil.h
+//  ShapeFactory.h
 //  libraries/physcis/src
 //
 //  Created by Andrew Meadows 2014.12.01
@@ -9,8 +9,8 @@
 //  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
 //
 
-#ifndef hifi_ShapeInfoUtil_h
-#define hifi_ShapeInfoUtil_h
+#ifndef hifi_ShapeFactory_h
+#define hifi_ShapeFactory_h
 
 #include <btBulletDynamicsCommon.h>
 #include <glm/glm.hpp>
@@ -20,11 +20,11 @@
 // translates between ShapeInfo and btShape
 
 // TODO: rename this to ShapeFactory
-namespace ShapeInfoUtil {
+namespace ShapeFactory {
 
     btConvexHullShape* createConvexHull(const QVector<glm::vec3>& points);
 
     btCollisionShape* createShapeFromInfo(const ShapeInfo& info);
 };
 
-#endif // hifi_ShapeInfoUtil_h
+#endif // hifi_ShapeFactory_h
diff --git a/libraries/physics/src/ShapeManager.cpp b/libraries/physics/src/ShapeManager.cpp
index dd67c2c73a..7a3065dfff 100644
--- a/libraries/physics/src/ShapeManager.cpp
+++ b/libraries/physics/src/ShapeManager.cpp
@@ -13,7 +13,7 @@
 
 #include <glm/gtx/norm.hpp>
 
-#include "ShapeInfoUtil.h"
+#include "ShapeFactory.h"
 #include "ShapeManager.h"
 
 ShapeManager::ShapeManager() {
@@ -46,7 +46,7 @@ btCollisionShape* ShapeManager::getShape(const ShapeInfo& info) {
         shapeRef->refCount++;
         return shapeRef->shape;
     }
-    btCollisionShape* shape = ShapeInfoUtil::createShapeFromInfo(info);
+    btCollisionShape* shape = ShapeFactory::createShapeFromInfo(info);
     if (shape) {
         ShapeReference newRef;
         newRef.refCount = 1;
diff --git a/libraries/physics/src/ThreadSafeDynamicsWorld.cpp b/libraries/physics/src/ThreadSafeDynamicsWorld.cpp
index a2d3ee97d3..b59103339c 100644
--- a/libraries/physics/src/ThreadSafeDynamicsWorld.cpp
+++ b/libraries/physics/src/ThreadSafeDynamicsWorld.cpp
@@ -17,7 +17,6 @@
 
 #include <LinearMath/btQuickprof.h>
 
-#include "ObjectMotionState.h"
 #include "ThreadSafeDynamicsWorld.h"
 
 ThreadSafeDynamicsWorld::ThreadSafeDynamicsWorld(
diff --git a/libraries/physics/src/ThreadSafeDynamicsWorld.h b/libraries/physics/src/ThreadSafeDynamicsWorld.h
index 4a96eae311..eacc8ad74a 100644
--- a/libraries/physics/src/ThreadSafeDynamicsWorld.h
+++ b/libraries/physics/src/ThreadSafeDynamicsWorld.h
@@ -21,7 +21,7 @@
 #include <BulletDynamics/Dynamics/btRigidBody.h>
 #include <BulletDynamics/Dynamics/btDiscreteDynamicsWorld.h>
 
-#include "PhysicsTypedefs.h"
+#include "ObjectMotionState.h"
 
 ATTRIBUTE_ALIGNED16(class) ThreadSafeDynamicsWorld : public btDiscreteDynamicsWorld {
 public:
diff --git a/libraries/shared/src/ShapeInfo.cpp b/libraries/shared/src/ShapeInfo.cpp
index ca812532fa..1d0cd56b86 100644
--- a/libraries/shared/src/ShapeInfo.cpp
+++ b/libraries/shared/src/ShapeInfo.cpp
@@ -17,7 +17,7 @@
 
 void ShapeInfo::clear() {
     _type = SHAPE_TYPE_NONE;
-    _halfExtents = glm::vec3(0.0f);
+    _halfExtents = _offset = glm::vec3(0.0f);
     _doubleHashKey.clear();
 }
 
@@ -45,6 +45,7 @@ void ShapeInfo::setParams(ShapeType type, const glm::vec3& halfExtents, QString
             _halfExtents = halfExtents;
             break;
     }
+    _doubleHashKey.clear();
 }
 
 void ShapeInfo::setBox(const glm::vec3& halfExtents) {
@@ -85,6 +86,11 @@ void ShapeInfo::setCapsuleY(float radius, float halfHeight) {
     _doubleHashKey.clear();
 }
 
+void ShapeInfo::setOffset(const glm::vec3& offset) {
+    _offset = offset;
+    _doubleHashKey.clear();
+}
+
 uint32_t ShapeInfo::getNumSubShapes() const {
     if (_type == SHAPE_TYPE_NONE) {
         return 0;
@@ -175,6 +181,7 @@ bool ShapeInfo::contains(const glm::vec3& point) const {
 const DoubleHashKey& ShapeInfo::getHash() const {
     // NOTE: we cache the key so we only ever need to compute it once for any valid ShapeInfo instance.
     if (_doubleHashKey.isNull() && _type != SHAPE_TYPE_NONE) {
+        bool useOffset = glm::length2(_offset) > MIN_SHAPE_OFFSET * MIN_SHAPE_OFFSET;
         // The key is not yet cached therefore we must compute it!  To this end we bypass the const-ness
         // of this method by grabbing a non-const pointer to "this" and a non-const reference to _doubleHashKey.
         ShapeInfo* thisPtr = const_cast<ShapeInfo*>(this);
@@ -190,9 +197,14 @@ const DoubleHashKey& ShapeInfo::getHash() const {
         for (int j = 0; j < 3; ++j) {
             // NOTE: 0.49f is used to bump the float up almost half a millimeter
             // so the cast to int produces a round() effect rather than a floor()
-            uint32_t floatHash =
-                DoubleHashKey::hashFunction((uint32_t)(_halfExtents[j] * MILLIMETERS_PER_METER + copysignf(1.0f, _halfExtents[j]) * 0.49f), primeIndex++);
-            hash ^= floatHash;
+            hash ^= DoubleHashKey::hashFunction(
+                    (uint32_t)(_halfExtents[j] * MILLIMETERS_PER_METER + copysignf(1.0f, _halfExtents[j]) * 0.49f), 
+                    primeIndex++);
+            if (useOffset) {
+                hash ^= DoubleHashKey::hashFunction(
+                        (uint32_t)(_offset[j] * MILLIMETERS_PER_METER + copysignf(1.0f, _offset[j]) * 0.49f), 
+                        primeIndex++);
+            }
         }
         key.setHash(hash);
     
@@ -201,8 +213,12 @@ const DoubleHashKey& ShapeInfo::getHash() const {
         for (int j = 0; j < 3; ++j) {
             // NOTE: 0.49f is used to bump the float up almost half a millimeter
             // so the cast to int produces a round() effect rather than a floor()
-            uint32_t floatHash =
-                DoubleHashKey::hashFunction2((uint32_t)(_halfExtents[j] * MILLIMETERS_PER_METER + copysignf(1.0f, _halfExtents[j]) * 0.49f));
+            uint32_t floatHash = DoubleHashKey::hashFunction2(
+                    (uint32_t)(_halfExtents[j] * MILLIMETERS_PER_METER + copysignf(1.0f, _halfExtents[j]) * 0.49f));
+            if (useOffset) {
+                floatHash ^= DoubleHashKey::hashFunction2(
+                        (uint32_t)(_offset[j] * MILLIMETERS_PER_METER + copysignf(1.0f, _offset[j]) * 0.49f));
+            }
             hash += ~(floatHash << 17);
             hash ^=  (floatHash >> 11);
             hash +=  (floatHash << 4);
diff --git a/libraries/shared/src/ShapeInfo.h b/libraries/shared/src/ShapeInfo.h
index e10cf1a149..a3fbe55f36 100644
--- a/libraries/shared/src/ShapeInfo.h
+++ b/libraries/shared/src/ShapeInfo.h
@@ -16,9 +16,12 @@
 #include <QString>
 #include <QUrl>
 #include <glm/glm.hpp>
+#include <glm/gtx/norm.hpp>
 
 #include "DoubleHashKey.h"
 
+const float MIN_SHAPE_OFFSET = 0.001f; // offsets less than 1mm will be ignored
+
 enum ShapeType {
     SHAPE_TYPE_NONE,
     SHAPE_TYPE_BOX,
@@ -46,10 +49,12 @@ public:
     void setEllipsoid(const glm::vec3& halfExtents);
     void setConvexHulls(const QVector<QVector<glm::vec3>>& points);
     void setCapsuleY(float radius, float halfHeight);
+    void setOffset(const glm::vec3& offset);
 
     int getType() const { return _type; }
 
     const glm::vec3& getHalfExtents() const { return _halfExtents; }
+    const glm::vec3& getOffset() const { return _offset; }
 
     const QVector<QVector<glm::vec3>>& getPoints() const { return _points; }
     uint32_t getNumSubShapes() const;
@@ -68,6 +73,7 @@ public:
 protected:
     ShapeType _type = SHAPE_TYPE_NONE;
     glm::vec3 _halfExtents = glm::vec3(0.0f);
+    glm::vec3 _offset = glm::vec3(0.0f);
     DoubleHashKey _doubleHashKey;
     QVector<QVector<glm::vec3>> _points; // points for convex collision hulls
     QUrl _url; // url for model of convex collision hulls
diff --git a/tests/physics/src/ShapeInfoTests.cpp b/tests/physics/src/ShapeInfoTests.cpp
index ef5bd0be39..365d6d6008 100644
--- a/tests/physics/src/ShapeInfoTests.cpp
+++ b/tests/physics/src/ShapeInfoTests.cpp
@@ -16,7 +16,7 @@
 
 #include <DoubleHashKey.h>
 #include <ShapeInfo.h>
-#include <ShapeInfoUtil.h>
+#include <ShapeFactory.h>
 #include <StreamUtils.h>
 
 #include "ShapeInfoTests.h"
@@ -142,7 +142,7 @@ void ShapeInfoTests::testBoxShape() {
     info.setBox(halfExtents);
     DoubleHashKey key = info.getHash();
 
-    btCollisionShape* shape = ShapeInfoUtil::createShapeFromInfo(info);
+    btCollisionShape* shape = ShapeFactory::createShapeFromInfo(info);
     if (!shape) {
         std::cout << __FILE__ << ":" << __LINE__ << " ERROR: NULL Box shape" << std::endl;
     }
@@ -168,7 +168,7 @@ void ShapeInfoTests::testSphereShape() {
     info.setSphere(radius);
     DoubleHashKey key = info.getHash();
 
-    btCollisionShape* shape = ShapeInfoUtil::createShapeFromInfo(info);
+    btCollisionShape* shape = ShapeFactory::createShapeFromInfo(info);
 
     ShapeInfo otherInfo = info;
     DoubleHashKey otherKey = otherInfo.getHash();
@@ -192,7 +192,7 @@ void ShapeInfoTests::testCylinderShape() {
     info.setCylinder(radius, height);
     DoubleHashKey key = info.getHash();
 
-    btCollisionShape* shape = ShapeInfoUtil::createShapeFromInfo(info);
+    btCollisionShape* shape = ShapeFactory::createShapeFromInfo(info);
 
     ShapeInfo otherInfo = info;
     DoubleHashKey otherKey = otherInfo.getHash();
@@ -217,7 +217,7 @@ void ShapeInfoTests::testCapsuleShape() {
     info.setCapsule(radius, height);
     DoubleHashKey key = info.getHash();
 
-    btCollisionShape* shape = ShapeInfoUtil::createShapeFromInfo(info);
+    btCollisionShape* shape = ShapeFactory::createShapeFromInfo(info);
 
     ShapeInfo otherInfo = info;
     DoubleHashKey otherKey = otherInfo.getHash();
diff --git a/tests/physics/src/ShapeManagerTests.cpp b/tests/physics/src/ShapeManagerTests.cpp
index d2b4ca70fa..9ac75981dd 100644
--- a/tests/physics/src/ShapeManagerTests.cpp
+++ b/tests/physics/src/ShapeManagerTests.cpp
@@ -10,7 +10,6 @@
 //
 
 #include <iostream>
-#include <ShapeInfoUtil.h>
 #include <ShapeManager.h>
 #include <StreamUtils.h>