diff --git a/libraries/entities/src/EntityTree.cpp b/libraries/entities/src/EntityTree.cpp
index e77134413c..97647501ea 100644
--- a/libraries/entities/src/EntityTree.cpp
+++ b/libraries/entities/src/EntityTree.cpp
@@ -37,7 +37,7 @@ EntityTreeElement* EntityTree::createNewElement(unsigned char * octalCode) {
 void EntityTree::eraseAllOctreeElements(bool createNewRoot) {
     // this would be a good place to clean up our entities...
     foreach (EntityTreeElement* element, _entityToElementMap) {
-        element->cleanupEntities();
+        element->cleanupEntities(_physicsWorld);
     }
     _entityToElementMap.clear();
     Octree::eraseAllOctreeElements(createNewRoot);
@@ -91,6 +91,7 @@ void EntityTree::addEntityItem(EntityItem* entityItem) {
     recurseTreeWithOperator(&theOperator);
 
     // check to see if we need to simulate this entity..
+    // BOOKMARK -- add entity to physics engine here
     changeEntityState(entityItem, EntityItem::Static, entityItem->getSimulationState());
 
     _isDirty = true;
@@ -133,7 +134,9 @@ bool EntityTree::updateEntity(const EntityItemID& entityID, const EntityItemProp
         _isDirty = true;
 
         EntityItem::SimulationState newState = existingEntity->getSimulationState();
-        changeEntityState(existingEntity, oldState, newState);
+        if (newState != oldState) {
+            changeEntityState(existingEntity, oldState, newState);
+        }
 
         QString entityScriptAfter = existingEntity->getScript();
         if (entityScriptBefore != entityScriptAfter) {
diff --git a/libraries/entities/src/EntityTreeElement.cpp b/libraries/entities/src/EntityTreeElement.cpp
index 1dea2bcd85..b26db16f89 100644
--- a/libraries/entities/src/EntityTreeElement.cpp
+++ b/libraries/entities/src/EntityTreeElement.cpp
@@ -16,7 +16,9 @@
 
 #include <FBXReader.h>
 #include <GeometryUtil.h>
+#include <PhysicsWorld.h>
 
+#include "EntityMotionState.h"
 #include "EntityTree.h"
 #include "EntityTreeElement.h"
 
@@ -653,10 +655,16 @@ EntityItem* EntityTreeElement::getEntityWithEntityItemID(const EntityItemID& id)
     return foundEntity;
 }
 
-void EntityTreeElement::cleanupEntities() {
+void EntityTreeElement::cleanupEntities(PhysicsWorld* physicsWorld) {
     uint16_t numberOfEntities = _entityItems->size();
     for (uint16_t i = 0; i < numberOfEntities; i++) {
         EntityItem* entity = (*_entityItems)[i];
+        EntityMotionState* motionState = entity->getMotionState();
+        if (motionState) {
+            assert(physicsWorld);
+            physicsWorld->removeEntity(static_cast<CustomMotionState*>(motionState));
+            entity->destroyMotionState();
+        }
         delete entity;
     }
     _entityItems->clear();
diff --git a/libraries/entities/src/EntityTreeElement.h b/libraries/entities/src/EntityTreeElement.h
index ab3754749b..7e26aacf1c 100644
--- a/libraries/entities/src/EntityTreeElement.h
+++ b/libraries/entities/src/EntityTreeElement.h
@@ -21,6 +21,7 @@
 
 class EntityTree;
 class EntityTreeElement;
+class PhysicsWorld;
 
 class EntityTreeUpdateArgs {
 public:
@@ -175,7 +176,7 @@ public:
 
     EntityItem* getEntityWithEntityItemID(const EntityItemID& id);
 
-    void cleanupEntities(); /// called by EntityTree on cleanup this will free all entities
+    void cleanupEntities(PhysicsWorld* physicsWorld);
     bool removeEntityWithEntityItemID(const EntityItemID& id);
     bool removeEntityItem(EntityItem* entity);