diff --git a/interface/src/avatar/MyAvatar.h b/interface/src/avatar/MyAvatar.h
index 5ebf72b215..b48e61718c 100644
--- a/interface/src/avatar/MyAvatar.h
+++ b/interface/src/avatar/MyAvatar.h
@@ -14,7 +14,7 @@
 
 #include <QSettings>
 
-#include <SimulationEngine.h>
+#include <PhysicsSimulation.h>
 
 #include "Avatar.h"
 
@@ -175,7 +175,7 @@ private:
     float _oculusYawOffset;
 
     QList<AnimationHandlePointer> _animationHandles;
-    SimulationEngine _simulationEngine;
+    PhysicsSimulation _simulationEngine;
 
 	// private methods
     float computeDistanceToFloor(const glm::vec3& startPoint);
diff --git a/interface/src/renderer/Model.cpp b/interface/src/renderer/Model.cpp
index 89a57c14af..515dcd4f27 100644
--- a/interface/src/renderer/Model.cpp
+++ b/interface/src/renderer/Model.cpp
@@ -18,7 +18,7 @@
 
 #include <CapsuleShape.h>
 #include <GeometryUtil.h>
-#include <PhysicalEntity.h>
+#include <PhysicsEntity.h>
 #include <ShapeCollider.h>
 #include <SphereShape.h>
 
@@ -561,7 +561,7 @@ void Model::setJointStates(QVector<JointState> states) {
     _jointStates = states;
 
     // compute an approximate bounding radius for broadphase collision queries
-    // against SimulationEngine boundaries
+    // against PhysicsSimulation boundaries
     int numJoints = _jointStates.size();
     float radius = 0.0f;
     for (int i = 0; i < numJoints; ++i) {
@@ -785,7 +785,7 @@ AnimationHandlePointer Model::createAnimationHandle() {
     return handle;
 }
 
-// virtual override from PhysicalEntity
+// virtual override from PhysicsEntity
 void Model::buildShapes() {
     // TODO: figure out how to load/build collision shapes for general models
 }
diff --git a/interface/src/renderer/Model.h b/interface/src/renderer/Model.h
index 8851f42eb1..2045a0c9b5 100644
--- a/interface/src/renderer/Model.h
+++ b/interface/src/renderer/Model.h
@@ -16,7 +16,7 @@
 #include <QObject>
 #include <QUrl>
 
-#include <PhysicalEntity.h>
+#include <PhysicsEntity.h>
 
 #include <AnimationCache.h>
 
@@ -33,7 +33,7 @@ typedef QSharedPointer<AnimationHandle> AnimationHandlePointer;
 typedef QWeakPointer<AnimationHandle> WeakAnimationHandlePointer;
 
 /// A generic 3D model displaying geometry loaded from a URL.
-class Model : public QObject, public PhysicalEntity {
+class Model : public QObject, public PhysicsEntity {
     Q_OBJECT
     
 public:
@@ -131,7 +131,7 @@ public:
 
     const QList<AnimationHandlePointer>& getRunningAnimations() const { return _runningAnimations; }
    
-    // virtual overrides from PhysicalEntity
+    // virtual overrides from PhysicsEntity
     virtual void buildShapes();
     virtual void updateShapePositions();
 
diff --git a/libraries/shared/src/PhysicalEntity.cpp b/libraries/shared/src/PhysicsEntity.cpp
similarity index 83%
rename from libraries/shared/src/PhysicalEntity.cpp
rename to libraries/shared/src/PhysicsEntity.cpp
index 87d8e982c6..10c08a3cea 100644
--- a/libraries/shared/src/PhysicalEntity.cpp
+++ b/libraries/shared/src/PhysicsEntity.cpp
@@ -1,5 +1,5 @@
 //
-//  PhysicalEntity.cpp
+//  PhysicsEntity.cpp
 //  libraries/shared/src
 //
 //  Created by Andrew Meadows 2014.06.11
@@ -9,11 +9,11 @@
 //  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
 //
 
-#include "PhysicalEntity.h"
+#include "PhysicsEntity.h"
 #include "Shape.h"
 #include "ShapeCollider.h"
 
-PhysicalEntity::PhysicalEntity() : 
+PhysicsEntity::PhysicsEntity() : 
     _translation(0.0f), 
     _rotation(), 
     _boundingRadius(0.0f), 
@@ -22,26 +22,26 @@ PhysicalEntity::PhysicalEntity() :
     _simulation(NULL) {
 }
 
-PhysicalEntity::~PhysicalEntity() {
+PhysicsEntity::~PhysicsEntity() {
     // entity should be removed from the simulation before it is deleted
     assert(_simulation == NULL);
 }
 
-void PhysicalEntity::setTranslation(const glm::vec3& translation) {
+void PhysicsEntity::setTranslation(const glm::vec3& translation) {
     if (_translation != translation) {
         _shapesAreDirty = !_shapes.isEmpty();
         _translation = translation;
     }
 }
 
-void PhysicalEntity::setRotation(const glm::quat& rotation) {
+void PhysicsEntity::setRotation(const glm::quat& rotation) {
     if (_rotation != rotation) {
         _shapesAreDirty = !_shapes.isEmpty();
         _rotation = rotation;
     }
 }   
 
-void PhysicalEntity::setShapeBackPointers() {
+void PhysicsEntity::setShapeBackPointers() {
     for (int i = 0; i < _shapes.size(); i++) {
         Shape* shape = _shapes[i];
         if (shape) {
@@ -50,7 +50,7 @@ void PhysicalEntity::setShapeBackPointers() {
     }
 }
 
-void PhysicalEntity::setEnableShapes(bool enable) {
+void PhysicsEntity::setEnableShapes(bool enable) {
     if (enable != _enableShapes) {
         clearShapes();
         _enableShapes = enable;
@@ -60,14 +60,14 @@ void PhysicalEntity::setEnableShapes(bool enable) {
     }
 }   
 
-void PhysicalEntity::clearShapes() {
+void PhysicsEntity::clearShapes() {
     for (int i = 0; i < _shapes.size(); ++i) {
         delete _shapes[i];
     }
     _shapes.clear();
 }
 
-bool PhysicalEntity::findRayIntersection(const glm::vec3& origin, const glm::vec3& direction, float& distance) const {
+bool PhysicsEntity::findRayIntersection(const glm::vec3& origin, const glm::vec3& direction, float& distance) const {
     /* TODO: Andrew to make this work
     int numShapes = _shapes.size();
     float minDistance = FLT_MAX;
@@ -88,7 +88,7 @@ bool PhysicalEntity::findRayIntersection(const glm::vec3& origin, const glm::vec
     return false;
 }
 
-bool PhysicalEntity::findCollisions(const QVector<const Shape*> shapes, CollisionList& collisions) {
+bool PhysicsEntity::findCollisions(const QVector<const Shape*> shapes, CollisionList& collisions) {
     bool collided = false;
     int numTheirShapes = shapes.size();
     for (int i = 0; i < numTheirShapes; ++i) {
@@ -107,7 +107,7 @@ bool PhysicalEntity::findCollisions(const QVector<const Shape*> shapes, Collisio
     return collided;
 }
 
-bool PhysicalEntity::findSphereCollisions(const glm::vec3& sphereCenter, float sphereRadius,
+bool PhysicsEntity::findSphereCollisions(const glm::vec3& sphereCenter, float sphereRadius,
     CollisionList& collisions, int skipIndex) {
     bool collided = false;
     // TODO: Andrew to implement this or make it unecessary
@@ -144,7 +144,7 @@ bool PhysicalEntity::findSphereCollisions(const glm::vec3& sphereCenter, float s
     return collided;
 }
 
-bool PhysicalEntity::findPlaneCollisions(const glm::vec4& plane, CollisionList& collisions) {
+bool PhysicsEntity::findPlaneCollisions(const glm::vec4& plane, CollisionList& collisions) {
     bool collided = false;
     PlaneShape planeShape(plane);
     for (int i = 0; i < _shapes.size(); i++) {
diff --git a/libraries/shared/src/PhysicalEntity.h b/libraries/shared/src/PhysicsEntity.h
similarity index 68%
rename from libraries/shared/src/PhysicalEntity.h
rename to libraries/shared/src/PhysicsEntity.h
index 959550dbb2..3e20115729 100644
--- a/libraries/shared/src/PhysicalEntity.h
+++ b/libraries/shared/src/PhysicsEntity.h
@@ -1,5 +1,5 @@
 //
-//  PhysicalEntity.h
+//  PhysicsEntity.h
 //  libraries/shared/src
 //
 //  Created by Andrew Meadows 2014.05.30
@@ -9,8 +9,8 @@
 //  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
 //
 
-#ifndef hifi_PhysicalEntity_h
-#define hifi_PhysicalEntity_h
+#ifndef hifi_PhysicsEntity_h
+#define hifi_PhysicsEntity_h
 
 #include <QVector>
 
@@ -20,17 +20,17 @@
 #include "CollisionInfo.h"
 
 class Shape;
-class SimulationEngine;
+class PhysicsSimulation;
 
-// PhysicalEntity is the base class for anything that owns one or more Shapes that collide in a 
-// SimulationEngine.  Each CollisionInfo generated by a SimulationEngine has back pointers to the 
-// two Shapes involved, and those Shapes may (optionally) have valid back pointers to their PhysicalEntity.
+// PhysicsEntity is the base class for anything that owns one or more Shapes that collide in a 
+// PhysicsSimulation.  Each CollisionInfo generated by a PhysicsSimulation has back pointers to the 
+// two Shapes involved, and those Shapes may (optionally) have valid back pointers to their PhysicsEntity.
 
-class PhysicalEntity {
+class PhysicsEntity {
 
 public:
-    PhysicalEntity();
-    virtual ~PhysicalEntity();
+    PhysicsEntity();
+    virtual ~PhysicsEntity();
 
     void setTranslation(const glm::vec3& translation);
     void setRotation(const glm::quat& rotation);
@@ -46,7 +46,7 @@ public:
     virtual void buildShapes() = 0;
     virtual void clearShapes();
 
-    SimulationEngine* getSimulation() const { return _simulation; }
+    PhysicsSimulation* getSimulation() const { return _simulation; }
 
     bool findRayIntersection(const glm::vec3& origin, const glm::vec3& direction, float& distance) const;
     bool findCollisions(const QVector<const Shape*> shapes, CollisionList& collisions);
@@ -54,8 +54,8 @@ public:
     bool findPlaneCollisions(const glm::vec4& plane, CollisionList& collisions);
 
 protected:
-    // SimulationEngine is a friend so that it can set the protected _simulation backpointer
-    friend SimulationEngine; 
+    // PhysicsSimulation is a friend so that it can set the protected _simulation backpointer
+    friend PhysicsSimulation; 
 
     glm::vec3 _translation;
     glm::quat _rotation;
@@ -63,7 +63,7 @@ protected:
     bool _shapesAreDirty;
     bool _enableShapes;
     QVector<Shape*> _shapes;
-    SimulationEngine* _simulation;
+    PhysicsSimulation* _simulation;
 };
 
-#endif // hifi_PhysicalEntity_h
+#endif // hifi_PhysicsEntity_h
diff --git a/libraries/shared/src/SimulationEngine.cpp b/libraries/shared/src/PhysicsSimulation.cpp
similarity index 82%
rename from libraries/shared/src/SimulationEngine.cpp
rename to libraries/shared/src/PhysicsSimulation.cpp
index bba33592e9..5fb6fa4a04 100644
--- a/libraries/shared/src/SimulationEngine.cpp
+++ b/libraries/shared/src/PhysicsSimulation.cpp
@@ -1,5 +1,5 @@
 //
-//  SimulationEngine.cpp
+//  PhysicsSimulation.cpp
 //  interface/src/avatar
 //
 //  Created by Andrew Meadows 2014.06.06
@@ -11,29 +11,29 @@
 
 #include <glm/glm.hpp>
 
-#include "SimulationEngine.h"
+#include "PhysicsSimulation.h"
 
-#include "PhysicalEntity.h"
+#include "PhysicsEntity.h"
 #include "Ragdoll.h"
 #include "SharedUtil.h"
 #include "ShapeCollider.h"
 
-int MAX_DOLLS_PER_ENGINE = 16;
-int MAX_ENTITIES_PER_ENGINE = 64;
-int MAX_COLLISIONS_PER_ENGINE = 256;
+int MAX_DOLLS_PER_SIMULATION = 16;
+int MAX_ENTITIES_PER_SIMULATION = 64;
+int MAX_COLLISIONS_PER_SIMULATION = 256;
 
 
 const int NUM_SHAPE_BITS = 6;
 const int SHAPE_INDEX_MASK = (1 << (NUM_SHAPE_BITS + 1)) - 1;
 
-SimulationEngine::SimulationEngine() : _collisionList(MAX_COLLISIONS_PER_ENGINE) {
+PhysicsSimulation::PhysicsSimulation() : _collisionList(MAX_COLLISIONS_PER_SIMULATION) {
 }
 
-SimulationEngine::~SimulationEngine() {
+PhysicsSimulation::~PhysicsSimulation() {
     _dolls.clear();
 }
 
-bool SimulationEngine::addEntity(PhysicalEntity* entity) {
+bool PhysicsSimulation::addEntity(PhysicsEntity* entity) {
     if (!entity) {
         return false;
     }
@@ -50,7 +50,7 @@ bool SimulationEngine::addEntity(PhysicalEntity* entity) {
         return false;
     }
     int numEntities = _entities.size();
-    if (numEntities > MAX_ENTITIES_PER_ENGINE) {
+    if (numEntities > MAX_ENTITIES_PER_SIMULATION) {
         // list is full
         return false;
     }
@@ -60,7 +60,7 @@ bool SimulationEngine::addEntity(PhysicalEntity* entity) {
     return true;
 }
 
-void SimulationEngine::removeEntity(PhysicalEntity* entity) {
+void PhysicsSimulation::removeEntity(PhysicsEntity* entity) {
     if (!entity || !entity->_simulation || !(entity->_simulation == this)) {
         return;
     }
@@ -72,7 +72,7 @@ void SimulationEngine::removeEntity(PhysicalEntity* entity) {
                 _entities.pop_back();
             } else {
                 // swap the last for this one
-                PhysicalEntity* lastEntity = _entities[numEntities - 1];
+                PhysicsEntity* lastEntity = _entities[numEntities - 1];
                 _entities.pop_back();
                 _entities[i] = lastEntity;
             }
@@ -82,12 +82,12 @@ void SimulationEngine::removeEntity(PhysicalEntity* entity) {
     }
 }
 
-bool SimulationEngine::addRagdoll(Ragdoll* doll) {
+bool PhysicsSimulation::addRagdoll(Ragdoll* doll) {
     if (!doll) {
         return false;
     }
     int numDolls = _dolls.size();
-    if (numDolls > MAX_DOLLS_PER_ENGINE) {
+    if (numDolls > MAX_DOLLS_PER_SIMULATION) {
         // list is full
         return false;
     }
@@ -102,7 +102,7 @@ bool SimulationEngine::addRagdoll(Ragdoll* doll) {
     return true;
 }
 
-void SimulationEngine::removeRagdoll(Ragdoll* doll) {
+void PhysicsSimulation::removeRagdoll(Ragdoll* doll) {
     int numDolls = _dolls.size();
     for (int i = 0; i < numDolls; ++i) {
         if (doll == _dolls[i]) {
@@ -120,7 +120,7 @@ void SimulationEngine::removeRagdoll(Ragdoll* doll) {
     }
 }
 
-void SimulationEngine::stepForward(float deltaTime, float minError, int maxIterations, quint64 maxUsec) {
+void PhysicsSimulation::stepForward(float deltaTime, float minError, int maxIterations, quint64 maxUsec) {
     /* TODO: Andrew to make this work
     int iterations = 0;
     float delta = 0.0f;
@@ -143,7 +143,7 @@ void SimulationEngine::stepForward(float deltaTime, float minError, int maxItera
     
     // collide
     _collisionList.clear();
-    // TODO: keep track of QSet<PhysicalEntity*> collidedEntities;
+    // TODO: keep track of QSet<PhysicsEntity*> collidedEntities;
     for (int i = 0; i < numDolls; ++i) {
         const QVector<Shape*>* shapesA = _dolls.at(i)->getShapes();
         if (!shapesA) {
@@ -186,10 +186,10 @@ void SimulationEngine::stepForward(float deltaTime, float minError, int maxItera
     */
 }
 
-int SimulationEngine::computeCollisions() {
+int PhysicsSimulation::computeCollisions() {
     return 0.0f;
 }
 
-void SimulationEngine::processCollisions() {
+void PhysicsSimulation::processCollisions() {
 }
 
diff --git a/libraries/shared/src/SimulationEngine.h b/libraries/shared/src/PhysicsSimulation.h
similarity index 80%
rename from libraries/shared/src/SimulationEngine.h
rename to libraries/shared/src/PhysicsSimulation.h
index f064760b6e..b5667db351 100644
--- a/libraries/shared/src/SimulationEngine.h
+++ b/libraries/shared/src/PhysicsSimulation.h
@@ -1,5 +1,5 @@
 //
-//  SimulationEngine.h
+//  PhysicsSimulation.h
 //  interface/src/avatar
 //
 //  Created by Andrew Meadows 2014.06.06
@@ -9,26 +9,26 @@
 //  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
 //
 
-#ifndef hifi_SimulationEngine_h
-#define hifi_SimulationEngine_h
+#ifndef hifi_PhysicsSimulation
+#define hifi_PhysicsSimulation
 
 #include <QVector>
 
 #include "CollisionInfo.h"
 
-class PhysicalEntity;
+class PhysicsEntity;
 class Ragdoll;
 
-class SimulationEngine {
+class PhysicsSimulation {
 public:
 
-    SimulationEngine();
-    ~SimulationEngine();
+    PhysicsSimulation();
+    ~PhysicsSimulation();
 
     /// \return true if entity was added to or is already in the list
-    bool addEntity(PhysicalEntity* entity);
+    bool addEntity(PhysicsEntity* entity);
 
-    void removeEntity(PhysicalEntity* entity);
+    void removeEntity(PhysicsEntity* entity);
 
     /// \return true if doll was added to or is already in the list
     bool addRagdoll(Ragdoll* doll);
@@ -52,7 +52,7 @@ public:
 
 private:
     CollisionList _collisionList;
-    QVector<PhysicalEntity*> _entities;
+    QVector<PhysicsEntity*> _entities;
     QVector<Ragdoll*> _dolls;
 
     // some stats for performance queries
@@ -61,4 +61,4 @@ private:
     quint64 _enforcementTime;
 };
 
-#endif // hifi_SimulationEngine_h
+#endif // hifi_PhysicsSimulation
diff --git a/libraries/shared/src/Shape.h b/libraries/shared/src/Shape.h
index 0a03ae18e3..4926f598ba 100644
--- a/libraries/shared/src/Shape.h
+++ b/libraries/shared/src/Shape.h
@@ -15,7 +15,7 @@
 #include <glm/glm.hpp>
 #include <glm/gtc/quaternion.hpp>
 
-class PhysicalEntity;
+class PhysicsEntity;
 
 class Shape {
 public:
@@ -32,8 +32,8 @@ public:
 
     int getType() const { return _type; }
 
-    void setEntity(PhysicalEntity* entity) { _owningEntity = entity; }
-    PhysicalEntity* getEntity() const { return _owningEntity; }
+    void setEntity(PhysicsEntity* entity) { _owningEntity = entity; }
+    PhysicsEntity* getEntity() const { return _owningEntity; }
 
     float getBoundingRadius() const { return _boundingRadius; }
 
@@ -58,7 +58,7 @@ protected:
     void setBoundingRadius(float radius) { _boundingRadius = radius; }
 
     int _type;
-    PhysicalEntity* _owningEntity;
+    PhysicsEntity* _owningEntity;
     float _boundingRadius;
     glm::vec3 _translation;
     glm::quat _rotation;