diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSAPIXNA.cs b/OpenSim/Region/Physics/BulletSPlugin/BSAPIXNA.cs
index b6ff52bf5b..49b17305df 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSAPIXNA.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSAPIXNA.cs
@@ -129,7 +129,12 @@ private sealed class BulletConstraintXNA : BulletConstraint
         get { return "XNAConstraint"; }
     }
 }
+    internal int m_maxCollisions;
+    internal CollisionDesc[] m_collisionArray;
 
+    internal int m_maxUpdatesPerFrame;
+    internal EntityProperties[] m_updateArray;
+    
     private static int m_collisionsThisFrame;
     private BSScene PhysicsScene { get; set; }
 
@@ -148,92 +153,98 @@ private sealed class BulletConstraintXNA : BulletConstraint
     /// <param name="p_2"></param>
     public override bool RemoveObjectFromWorld(BulletWorld pWorld, BulletBody pBody)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
         RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
         world.RemoveRigidBody(body);
         return true;
     }
 
-    public override bool AddConstraintToWorld(BulletWorld world, BulletConstraint constrain, bool disableCollisionsBetweenLinkedObjects)
+    public override bool AddConstraintToWorld(BulletWorld pWorld, BulletConstraint pConstraint, bool pDisableCollisionsBetweenLinkedObjects)
     {
-        /* TODO */
-        return false;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        TypedConstraint constraint = (pConstraint as BulletConstraintXNA).constrain;
+        world.AddConstraint(constraint, pDisableCollisionsBetweenLinkedObjects);
+        
+        return true;
+
     }
 
-    public override bool RemoveConstraintFromWorld(BulletWorld world, BulletConstraint constrain)
+    public override bool RemoveConstraintFromWorld(BulletWorld pWorld, BulletConstraint pConstraint)
     {
-        /* TODO */
-        return false;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        TypedConstraint constraint = (pConstraint as BulletConstraintXNA).constrain;
+        world.RemoveConstraint(constraint);
+        return true;
     }
 
-    public override void SetRestitution(BulletBody pBody, float pRestitution)
+    public override void SetRestitution(BulletBody pCollisionObject, float pRestitution)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        body.SetRestitution(pRestitution);
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        collisionObject.SetRestitution(pRestitution);
     }
 
     public override int GetShapeType(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         return (int)shape.GetShapeType();
     }
     public override void SetMargin(BulletShape pShape, float pMargin)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         shape.SetMargin(pMargin);
     }
 
     public override float GetMargin(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         return shape.GetMargin();
     }
 
     public override void SetLocalScaling(BulletShape pShape, Vector3 pScale)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         IndexedVector3 vec = new IndexedVector3(pScale.X, pScale.Y, pScale.Z);
         shape.SetLocalScaling(ref vec);
 
     }
 
-    public override void SetContactProcessingThreshold(BulletBody pBody, float contactprocessingthreshold)
+    public override void SetContactProcessingThreshold(BulletBody pCollisionObject, float contactprocessingthreshold)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        body.SetContactProcessingThreshold(contactprocessingthreshold);
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        collisionObject.SetContactProcessingThreshold(contactprocessingthreshold);
     }
 
-    public override void SetCcdMotionThreshold(BulletBody pBody, float pccdMotionThreashold)
+    public override void SetCcdMotionThreshold(BulletBody pCollisionObject, float pccdMotionThreashold)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        body.SetCcdMotionThreshold(pccdMotionThreashold);
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        collisionObject.SetCcdMotionThreshold(pccdMotionThreashold);
     }
 
-    public override void SetCcdSweptSphereRadius(BulletBody pBody, float pCcdSweptSphereRadius)
+    public override void SetCcdSweptSphereRadius(BulletBody pCollisionObject, float pCcdSweptSphereRadius)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        body.SetCcdSweptSphereRadius(pCcdSweptSphereRadius);
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        collisionObject.SetCcdSweptSphereRadius(pCcdSweptSphereRadius);
     }
 
     public override void SetAngularFactorV(BulletBody pBody, Vector3 pAngularFactor)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         body.SetAngularFactor(new IndexedVector3(pAngularFactor.X, pAngularFactor.Y, pAngularFactor.Z));
     }
 
-    public override CollisionFlags AddToCollisionFlags(BulletBody pBody, CollisionFlags pcollisionFlags)
+    public override CollisionFlags AddToCollisionFlags(BulletBody pCollisionObject, CollisionFlags pcollisionFlags)
     {
-        CollisionObject body = ((BulletBodyXNA)pBody).body;
-        CollisionFlags existingcollisionFlags = (CollisionFlags)(uint)body.GetCollisionFlags();
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).body;
+        CollisionFlags existingcollisionFlags = (CollisionFlags)(uint)collisionObject.GetCollisionFlags();
         existingcollisionFlags |= pcollisionFlags;
-        body.SetCollisionFlags((BulletXNA.BulletCollision.CollisionFlags)(uint)existingcollisionFlags);
+        collisionObject.SetCollisionFlags((BulletXNA.BulletCollision.CollisionFlags)(uint)existingcollisionFlags);
         return (CollisionFlags) (uint) existingcollisionFlags;
     }
 
     public override bool AddObjectToWorld(BulletWorld pWorld, BulletBody pBody)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
-        CollisionObject cbody = ((BulletBodyXNA)pBody).body;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        CollisionObject cbody = (pBody as BulletBodyXNA).body;
         RigidBody rbody = cbody as RigidBody;
 
         // Bullet resets several variables when an object is added to the world. In particular,
@@ -259,99 +270,110 @@ private sealed class BulletConstraintXNA : BulletConstraint
         return true;
     }
 
-    public override void ForceActivationState(BulletBody pBody, ActivationState pActivationState)
+    public override void ForceActivationState(BulletBody pCollisionObject, ActivationState pActivationState)
     {
-        CollisionObject body = ((BulletBodyXNA)pBody).body;
-        body.ForceActivationState((BulletXNA.BulletCollision.ActivationState)(uint)pActivationState);
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).body;
+        collisionObject.ForceActivationState((BulletXNA.BulletCollision.ActivationState)(uint)pActivationState);
     }
 
-    public override void UpdateSingleAabb(BulletWorld pWorld, BulletBody pBody)
+    public override void UpdateSingleAabb(BulletWorld pWorld, BulletBody pCollisionObject)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
-        CollisionObject body = ((BulletBodyXNA)pBody).body;
-        world.UpdateSingleAabb(body);
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).body;
+        world.UpdateSingleAabb(collisionObject);
     }
 
-    public override void UpdateAabbs(BulletWorld world) { /* TODO */ }
-    public override bool GetForceUpdateAllAabbs(BulletWorld world) { /* TODO */ return false;  }
-    public override void SetForceUpdateAllAabbs(BulletWorld world, bool force) { /* TODO */ }
-
-    public override bool SetCollisionGroupMask(BulletBody pBody, uint pGroup, uint pMask)
+    public override void UpdateAabbs(BulletWorld pWorld) {
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        world.UpdateAabbs();
+    }
+    public override bool GetForceUpdateAllAabbs(BulletWorld pWorld) {
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        return world.GetForceUpdateAllAabbs();
+        
+    }
+    public override void SetForceUpdateAllAabbs(BulletWorld pWorld, bool pForce)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        body.GetBroadphaseHandle().m_collisionFilterGroup = (BulletXNA.BulletCollision.CollisionFilterGroups) pGroup;
-        body.GetBroadphaseHandle().m_collisionFilterGroup = (BulletXNA.BulletCollision.CollisionFilterGroups) pGroup;
-        if ((uint) body.GetBroadphaseHandle().m_collisionFilterGroup == 0)
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        world.SetForceUpdateAllAabbs(pForce);
+    }
+
+    public override bool SetCollisionGroupMask(BulletBody pCollisionObject, uint pGroup, uint pMask)
+    {
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        collisionObject.GetBroadphaseHandle().m_collisionFilterGroup = (BulletXNA.BulletCollision.CollisionFilterGroups) pGroup;
+        collisionObject.GetBroadphaseHandle().m_collisionFilterGroup = (BulletXNA.BulletCollision.CollisionFilterGroups) pGroup;
+        if ((uint) collisionObject.GetBroadphaseHandle().m_collisionFilterGroup == 0)
             return false;
         return true;
     }
 
-    public override void ClearAllForces(BulletBody pBody)
+    public override void ClearAllForces(BulletBody pCollisionObject)
     {
-        CollisionObject body = ((BulletBodyXNA)pBody).body;
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).body;
         IndexedVector3 zeroVector = new IndexedVector3(0, 0, 0);
-        body.SetInterpolationLinearVelocity(ref zeroVector);
-        body.SetInterpolationAngularVelocity(ref zeroVector);
-        IndexedMatrix bodytransform = body.GetWorldTransform();
+        collisionObject.SetInterpolationLinearVelocity(ref zeroVector);
+        collisionObject.SetInterpolationAngularVelocity(ref zeroVector);
+        IndexedMatrix bodytransform = collisionObject.GetWorldTransform();
 
-        body.SetInterpolationWorldTransform(ref bodytransform);
+        collisionObject.SetInterpolationWorldTransform(ref bodytransform);
 
-        if (body is RigidBody)
+        if (collisionObject is RigidBody)
         {
-            RigidBody rigidbody = body as RigidBody;
+            RigidBody rigidbody = collisionObject as RigidBody;
             rigidbody.SetLinearVelocity(zeroVector);
             rigidbody.SetAngularVelocity(zeroVector);
             rigidbody.ClearForces();
         }
     }
 
-    public override void SetInterpolationAngularVelocity(BulletBody pBody, Vector3 pVector3)
+    public override void SetInterpolationAngularVelocity(BulletBody pCollisionObject, Vector3 pVector3)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
         IndexedVector3 vec = new IndexedVector3(pVector3.X, pVector3.Y, pVector3.Z);
-        body.SetInterpolationAngularVelocity(ref vec);
+        collisionObject.SetInterpolationAngularVelocity(ref vec);
     }
 
     public override void SetAngularVelocity(BulletBody pBody, Vector3 pVector3)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 vec = new IndexedVector3(pVector3.X, pVector3.Y, pVector3.Z);
         body.SetAngularVelocity(ref vec);
     }
     public override Vector3 GetTotalForce(BulletBody pBody)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 iv3 = body.GetTotalForce();
         return new Vector3(iv3.X, iv3.Y, iv3.Z);
     }
     public override Vector3 GetTotalTorque(BulletBody pBody)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 iv3 = body.GetTotalTorque();
         return new Vector3(iv3.X, iv3.Y, iv3.Z);
     }
     public override Vector3 GetInvInertiaDiagLocal(BulletBody pBody)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 iv3 = body.GetInvInertiaDiagLocal();
         return new Vector3(iv3.X, iv3.Y, iv3.Z);
     }
     public override void SetInvInertiaDiagLocal(BulletBody pBody, Vector3 inert)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 iv3 = new IndexedVector3(inert.X, inert.Y, inert.Z);
         body.SetInvInertiaDiagLocal(ref iv3);
     }
     public override void ApplyForce(BulletBody pBody, Vector3 force, Vector3 pos)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 forceiv3 = new IndexedVector3(force.X, force.Y, force.Z);
         IndexedVector3 posiv3 = new IndexedVector3(pos.X, pos.Y, pos.Z);
         body.ApplyForce(ref forceiv3, ref posiv3);
     }
     public override void ApplyImpulse(BulletBody pBody, Vector3 imp, Vector3 pos)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 impiv3 = new IndexedVector3(imp.X, imp.Y, imp.Z);
         IndexedVector3 posiv3 = new IndexedVector3(pos.X, pos.Y, pos.Z);
         body.ApplyImpulse(ref impiv3, ref posiv3);
@@ -359,32 +381,32 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override void ClearForces(BulletBody pBody)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         body.ClearForces();
     }
 
-    public override void SetTranslation(BulletBody pBody, Vector3 _position, Quaternion _orientation)
+    public override void SetTranslation(BulletBody pCollisionObject, Vector3 _position, Quaternion _orientation)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
         IndexedVector3 vposition = new IndexedVector3(_position.X, _position.Y, _position.Z);
         IndexedQuaternion vquaternion = new IndexedQuaternion(_orientation.X, _orientation.Y, _orientation.Z,
                                                               _orientation.W);
         IndexedMatrix mat = IndexedMatrix.CreateFromQuaternion(vquaternion);
         mat._origin = vposition;
-        body.SetWorldTransform(mat);
+        collisionObject.SetWorldTransform(mat);
         
     }
 
-    public override Vector3 GetPosition(BulletBody pBody)
+    public override Vector3 GetPosition(BulletBody pCollisionObject)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        IndexedVector3 pos = body.GetInterpolationWorldTransform()._origin;
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        IndexedVector3 pos = collisionObject.GetInterpolationWorldTransform()._origin;
         return new Vector3(pos.X, pos.Y, pos.Z);
     }
 
     public override Vector3 CalculateLocalInertia(BulletShape pShape, float pphysMass)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         IndexedVector3 inertia = IndexedVector3.Zero;
         shape.CalculateLocalInertia(pphysMass, out inertia);
         return new Vector3(inertia.X, inertia.Y, inertia.Z);
@@ -392,7 +414,7 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override void SetMassProps(BulletBody pBody, float pphysMass, Vector3 plocalInertia)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 inertia = new IndexedVector3(plocalInertia.X, plocalInertia.Y, plocalInertia.Z);
         body.SetMassProps(pphysMass, inertia);
     }
@@ -400,73 +422,90 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override void SetObjectForce(BulletBody pBody, Vector3 _force)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 force = new IndexedVector3(_force.X, _force.Y, _force.Z);
         body.SetTotalForce(ref force);
     }
 
-    public override void SetFriction(BulletBody pBody, float _currentFriction)
+    public override void SetFriction(BulletBody pCollisionObject, float _currentFriction)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        body.SetFriction(_currentFriction);
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        collisionObject.SetFriction(_currentFriction);
     }
 
     public override void SetLinearVelocity(BulletBody pBody, Vector3 _velocity)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 velocity = new IndexedVector3(_velocity.X, _velocity.Y, _velocity.Z);
         body.SetLinearVelocity(velocity);
     }
 
-    public override void Activate(BulletBody pBody, bool pforceactivation)
+    public override void Activate(BulletBody pCollisionObject, bool pforceactivation)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        body.Activate(pforceactivation);
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        collisionObject.Activate(pforceactivation);
         
     }
 
-    public override Quaternion GetOrientation(BulletBody pBody)
+    public override Quaternion GetOrientation(BulletBody pCollisionObject)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        IndexedQuaternion mat = body.GetInterpolationWorldTransform().GetRotation();
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        IndexedQuaternion mat = collisionObject.GetInterpolationWorldTransform().GetRotation();
         return new Quaternion(mat.X, mat.Y, mat.Z, mat.W);
     }
 
-    public override CollisionFlags RemoveFromCollisionFlags(BulletBody pBody, CollisionFlags pcollisionFlags)
+    public override CollisionFlags RemoveFromCollisionFlags(BulletBody pCollisionObject, CollisionFlags pcollisionFlags)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        CollisionFlags existingcollisionFlags = (CollisionFlags)(uint)body.GetCollisionFlags();
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        CollisionFlags existingcollisionFlags = (CollisionFlags)(uint)collisionObject.GetCollisionFlags();
         existingcollisionFlags &= ~pcollisionFlags;
-        body.SetCollisionFlags((BulletXNA.BulletCollision.CollisionFlags)(uint)existingcollisionFlags);
+        collisionObject.SetCollisionFlags((BulletXNA.BulletCollision.CollisionFlags)(uint)existingcollisionFlags);
         return (CollisionFlags)(uint)existingcollisionFlags;
     }
 
-    public override float GetCcdMotionThreshold(BulletBody obj) { /* TODO */ return 0f;  }
+    public override float GetCcdMotionThreshold(BulletBody pCollisionObject)
+    {
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        return collisionObject.GetCcdSquareMotionThreshold();
+    }
 
-    public override float GetCcdSweptSphereRadius(BulletBody obj) { /* TODO */ return 0f;  }
+    public override float GetCcdSweptSphereRadius(BulletBody pCollisionObject)
+    {
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        return collisionObject.GetCcdSweptSphereRadius();
+        
+    }
 
-    public override IntPtr GetUserPointer(BulletBody obj) { /* TODO */ return IntPtr.Zero;  }
+    public override IntPtr GetUserPointer(BulletBody pCollisionObject)
+    {
+        CollisionObject shape = (pCollisionObject as BulletBodyXNA).body;
+        return (IntPtr)shape.GetUserPointer();
+    }
 
-    public override void SetUserPointer(BulletBody obj, IntPtr val) { /* TODO */ }
+    public override void SetUserPointer(BulletBody pCollisionObject, IntPtr val)
+    {
+        CollisionObject shape = (pCollisionObject as BulletBodyXNA).body;
+        shape.SetUserPointer(val);
+    }
 
     public override void SetGravity(BulletBody pBody, Vector3 pGravity)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 gravity = new IndexedVector3(pGravity.X, pGravity.Y, pGravity.Z);
         body.SetGravity(gravity);
     }
 
     public override bool DestroyConstraint(BulletWorld pWorld, BulletConstraint pConstraint)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
-        TypedConstraint constraint = ((BulletConstraintXNA)pConstraint).constrain;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        TypedConstraint constraint = (pConstraint as BulletConstraintXNA).constrain;
         world.RemoveConstraint(constraint);
         return true;
     }
 
     public override bool SetLinearLimits(BulletConstraint pConstraint, Vector3 low, Vector3 high)
     {
-        Generic6DofConstraint constraint = ((BulletConstraintXNA)pConstraint).constrain as Generic6DofConstraint;
+        Generic6DofConstraint constraint = (pConstraint as BulletConstraintXNA).constrain as Generic6DofConstraint;
         IndexedVector3 lowlimit = new IndexedVector3(low.X, low.Y, low.Z);
         IndexedVector3 highlimit = new IndexedVector3(high.X, high.Y, high.Z);
         constraint.SetLinearLowerLimit(lowlimit);
@@ -476,7 +515,7 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override bool SetAngularLimits(BulletConstraint pConstraint, Vector3 low, Vector3 high)
     {
-        Generic6DofConstraint constraint = ((BulletConstraintXNA)pConstraint).constrain as Generic6DofConstraint;
+        Generic6DofConstraint constraint = (pConstraint as BulletConstraintXNA).constrain as Generic6DofConstraint;
         IndexedVector3 lowlimit = new IndexedVector3(low.X, low.Y, low.Z);
         IndexedVector3 highlimit = new IndexedVector3(high.X, high.Y, high.Z);
         constraint.SetAngularLowerLimit(lowlimit);
@@ -486,20 +525,20 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override void SetConstraintNumSolverIterations(BulletConstraint pConstraint, float cnt)
     {
-        Generic6DofConstraint constraint = ((BulletConstraintXNA)pConstraint).constrain as Generic6DofConstraint;
+        Generic6DofConstraint constraint = (pConstraint as BulletConstraintXNA).constrain as Generic6DofConstraint;
         constraint.SetOverrideNumSolverIterations((int)cnt);
     }
 
     public override bool CalculateTransforms(BulletConstraint pConstraint)
     {
-        Generic6DofConstraint constraint = ((BulletConstraintXNA)pConstraint).constrain as Generic6DofConstraint;
+        Generic6DofConstraint constraint = (pConstraint as BulletConstraintXNA).constrain as Generic6DofConstraint;
         constraint.CalculateTransforms();
         return true;
     }
 
     public override void SetConstraintEnable(BulletConstraint pConstraint, float p_2)
     {
-        Generic6DofConstraint constraint = ((BulletConstraintXNA)pConstraint).constrain as Generic6DofConstraint;
+        Generic6DofConstraint constraint = (pConstraint as BulletConstraintXNA).constrain as Generic6DofConstraint;
         constraint.SetEnabled((p_2 == 0) ? false : true);
     }
 
@@ -508,9 +547,9 @@ private sealed class BulletConstraintXNA : BulletConstraint
     public override BulletConstraint Create6DofConstraint(BulletWorld pWorld, BulletBody pBody1, BulletBody pBody2, Vector3 pframe1, Quaternion pframe1rot, Vector3 pframe2, Quaternion pframe2rot, bool puseLinearReferenceFrameA, bool pdisableCollisionsBetweenLinkedBodies)
 
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
-        RigidBody body1 = ((BulletBodyXNA)pBody1).rigidBody;
-        RigidBody body2 = ((BulletBodyXNA)pBody2).rigidBody;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        RigidBody body1 = (pBody1 as BulletBodyXNA).rigidBody;
+        RigidBody body2 = (pBody2 as BulletBodyXNA).rigidBody;
         IndexedVector3 frame1v = new IndexedVector3(pframe1.X, pframe1.Y, pframe1.Z);
         IndexedQuaternion frame1rot = new IndexedQuaternion(pframe1rot.X, pframe1rot.Y, pframe1rot.Z, pframe1rot.W);
         IndexedMatrix frame1 = IndexedMatrix.CreateFromQuaternion(frame1rot);
@@ -542,9 +581,9 @@ private sealed class BulletConstraintXNA : BulletConstraint
     /// <returns></returns>
     public override BulletConstraint Create6DofConstraintToPoint(BulletWorld pWorld, BulletBody pBody1, BulletBody pBody2, Vector3 pjoinPoint, bool puseLinearReferenceFrameA, bool pdisableCollisionsBetweenLinkedBodies)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
-        RigidBody body1 = ((BulletBodyXNA)pBody1).rigidBody;
-        RigidBody body2 = ((BulletBodyXNA)pBody2).rigidBody;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        RigidBody body1 = (pBody1 as BulletBodyXNA).rigidBody;
+        RigidBody body2 = (pBody2 as BulletBodyXNA).rigidBody;
         IndexedMatrix frame1 = new IndexedMatrix(IndexedBasisMatrix.Identity, new IndexedVector3(0, 0, 0));
         IndexedMatrix frame2 = new IndexedMatrix(IndexedBasisMatrix.Identity, new IndexedVector3(0, 0, 0));
 
@@ -563,7 +602,7 @@ private sealed class BulletConstraintXNA : BulletConstraint
     //SetFrames(m_constraint.ptr, frameA, frameArot, frameB, frameBrot);
     public override bool SetFrames(BulletConstraint pConstraint, Vector3 pframe1, Quaternion pframe1rot, Vector3 pframe2, Quaternion pframe2rot)
     {
-        Generic6DofConstraint constraint = ((BulletConstraintXNA)pConstraint).constrain as Generic6DofConstraint;
+        Generic6DofConstraint constraint = (pConstraint as BulletConstraintXNA).constrain as Generic6DofConstraint;
         IndexedVector3 frame1v = new IndexedVector3(pframe1.X, pframe1.Y, pframe1.Z);
         IndexedQuaternion frame1rot = new IndexedQuaternion(pframe1rot.X, pframe1rot.Y, pframe1rot.Z, pframe1rot.W);
         IndexedMatrix frame1 = IndexedMatrix.CreateFromQuaternion(frame1rot);
@@ -579,109 +618,110 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override Vector3 GetLinearVelocity(BulletBody pBody)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 iv3 = body.GetLinearVelocity();
         return new Vector3(iv3.X, iv3.Y, iv3.Z);
     }
     public override Vector3 GetAngularVelocity(BulletBody pBody)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 iv3 = body.GetAngularVelocity();
         return new Vector3(iv3.X, iv3.Y, iv3.Z);
     }
     public override Vector3 GetVelocityInLocalPoint(BulletBody pBody, Vector3 pos)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 posiv3 = new IndexedVector3(pos.X, pos.Y, pos.Z);
         IndexedVector3 iv3 = body.GetVelocityInLocalPoint(ref posiv3);
         return new Vector3(iv3.X, iv3.Y, iv3.Z);
     }
-    public override void Translate(BulletBody pBody, Vector3 trans)
+    public override void Translate(BulletBody pCollisionObject, Vector3 trans)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        collisionObject.Translate(new IndexedVector3(trans.X,trans.Y,trans.Z));
     }
     public override void UpdateDeactivation(BulletBody pBody, float timeStep)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         body.UpdateDeactivation(timeStep);
     }
 
     public override bool WantsSleeping(BulletBody pBody)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         return body.WantsSleeping();
     }
 
     public override void SetAngularFactor(BulletBody pBody, float factor)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         body.SetAngularFactor(factor);
     }
 
     public override Vector3 GetAngularFactor(BulletBody pBody)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 iv3 =  body.GetAngularFactor();
         return new Vector3(iv3.X, iv3.Y, iv3.Z);
     }
 
-    public override bool IsInWorld(BulletWorld pWorld, BulletBody pBody)
+    public override bool IsInWorld(BulletWorld pWorld, BulletBody pCollisionObject)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
-        CollisionObject body = ((BulletBodyXNA)pBody).body;
-        return world.IsInWorld(body);
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).body;
+        return world.IsInWorld(collisionObject);
     }
 
-    public override void AddConstraintRef(BulletBody pBody, BulletConstraint pConstrain)
+    public override void AddConstraintRef(BulletBody pBody, BulletConstraint pConstraint)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        TypedConstraint constrain = ((BulletConstraintXNA)pConstrain).constrain;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
+        TypedConstraint constrain = (pConstraint as BulletConstraintXNA).constrain;
         body.AddConstraintRef(constrain);
     }
 
-    public override void RemoveConstraintRef(BulletBody pBody, BulletConstraint pConstrain)
+    public override void RemoveConstraintRef(BulletBody pBody, BulletConstraint pConstraint)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        TypedConstraint constrain = ((BulletConstraintXNA)pConstrain).constrain;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
+        TypedConstraint constrain = (pConstraint as BulletConstraintXNA).constrain;
         body.RemoveConstraintRef(constrain);
     }
 
     public override BulletConstraint GetConstraintRef(BulletBody pBody, int index)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         return new BulletConstraintXNA(body.GetConstraintRef(index));
     }
 
     public override int GetNumConstraintRefs(BulletBody pBody)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         return body.GetNumConstraintRefs();
     }
 
-    public override void SetInterpolationLinearVelocity(BulletBody pBody, Vector3 VehicleVelocity)
+    public override void SetInterpolationLinearVelocity(BulletBody pCollisionObject, Vector3 VehicleVelocity)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
         IndexedVector3 velocity = new IndexedVector3(VehicleVelocity.X, VehicleVelocity.Y, VehicleVelocity.Z);
-        body.SetInterpolationLinearVelocity(ref velocity);
+        collisionObject.SetInterpolationLinearVelocity(ref velocity);
     }
 
     public override bool UseFrameOffset(BulletConstraint pConstraint, float onOff)
     {
-        Generic6DofConstraint constraint = ((BulletConstraintXNA)pConstraint).constrain as Generic6DofConstraint;
+        Generic6DofConstraint constraint = (pConstraint as BulletConstraintXNA).constrain as Generic6DofConstraint;
         constraint.SetUseFrameOffset((onOff == 0) ? false : true);
         return true;
     }
     //SetBreakingImpulseThreshold(m_constraint.ptr, threshold);
     public override bool SetBreakingImpulseThreshold(BulletConstraint pConstraint, float threshold)
     {
-        Generic6DofConstraint constraint = ((BulletConstraintXNA)pConstraint).constrain as Generic6DofConstraint;
+        Generic6DofConstraint constraint = (pConstraint as BulletConstraintXNA).constrain as Generic6DofConstraint;
         constraint.SetBreakingImpulseThreshold(threshold);
         return true;
     }
     //BulletSimAPI.SetAngularDamping(Prim.PhysBody.ptr, angularDamping);
     public override void SetAngularDamping(BulletBody pBody, float angularDamping)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         float lineardamping = body.GetLinearDamping();
         body.SetDamping(lineardamping, angularDamping);
 
@@ -689,111 +729,183 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override void UpdateInertiaTensor(BulletBody pBody)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         body.UpdateInertiaTensor();
     }
 
     public override void RecalculateCompoundShapeLocalAabb(BulletShape pCompoundShape)
     {
-        CompoundShape shape = ((BulletShapeXNA)pCompoundShape).shape as CompoundShape;
+        CompoundShape shape = (pCompoundShape as BulletShapeXNA).shape as CompoundShape;
         shape.RecalculateLocalAabb();
     }
 
     //BulletSimAPI.GetCollisionFlags(PhysBody.ptr)
-    public override CollisionFlags GetCollisionFlags(BulletBody pBody)
+    public override CollisionFlags GetCollisionFlags(BulletBody pCollisionObject)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        uint flags = (uint)body.GetCollisionFlags();
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        uint flags = (uint)collisionObject.GetCollisionFlags();
         return (CollisionFlags) flags;
     }
 
     public override void SetDamping(BulletBody pBody, float pLinear, float pAngular)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         body.SetDamping(pLinear, pAngular);
     }
     //PhysBody.ptr, PhysicsScene.Params.deactivationTime);
-    public override void SetDeactivationTime(BulletBody pBody, float pDeactivationTime)
+    public override void SetDeactivationTime(BulletBody pCollisionObject, float pDeactivationTime)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        body.SetDeactivationTime(pDeactivationTime);
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        collisionObject.SetDeactivationTime(pDeactivationTime);
     }
     //SetSleepingThresholds(PhysBody.ptr, PhysicsScene.Params.linearSleepingThreshold, PhysicsScene.Params.angularSleepingThreshold);
     public override void SetSleepingThresholds(BulletBody pBody, float plinearSleepingThreshold, float pangularSleepingThreshold)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         body.SetSleepingThresholds(plinearSleepingThreshold, pangularSleepingThreshold);
     }
 
-    public override CollisionObjectTypes GetBodyType(BulletBody pBody)
+    public override CollisionObjectTypes GetBodyType(BulletBody pCollisionObject)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        return (CollisionObjectTypes)(int) body.GetInternalType();
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        return (CollisionObjectTypes)(int) collisionObject.GetInternalType();
     }
 
-    public override void ApplyGravity(BulletBody obj) { /* TODO */ }
+    public override void ApplyGravity(BulletBody pBody)
+    {
 
-    public override Vector3 GetGravity(BulletBody obj) { /* TODO */ return Vector3.Zero;  }
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
+        body.ApplyGravity();
+    }
 
-    public override void SetLinearDamping(BulletBody obj, float lin_damping) { /* TODO */ }
+    public override Vector3 GetGravity(BulletBody pBody)
+    {
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
+        IndexedVector3 gravity = body.GetGravity();
+        return new Vector3(gravity.X, gravity.Y, gravity.Z);
+    }
 
-    public override float GetLinearDamping(BulletBody obj) { /* TODO */ return 0f;  }
+    public override void SetLinearDamping(BulletBody pBody, float lin_damping)
+    {
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
+        float angularDamping = body.GetAngularDamping();
+        body.SetDamping(lin_damping, angularDamping); 
+    }
 
-    public override float GetAngularDamping(BulletBody obj) { /* TODO */ return 0f;  }
+    public override float GetLinearDamping(BulletBody pBody)
+    {
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
+        return body.GetLinearDamping();
+    }
 
-    public override float GetLinearSleepingThreshold(BulletBody obj) { /* TODO */ return 0f;  }
+    public override float GetAngularDamping(BulletBody pBody)
+    {
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
+        return body.GetAngularDamping();
+    }
 
-    public override void ApplyDamping(BulletBody obj, float timeStep) { /* TODO */ }
+    public override float GetLinearSleepingThreshold(BulletBody pBody)
+    {
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
+        return body.GetLinearSleepingThreshold();
+    }
 
-    public override Vector3 GetLinearFactor(BulletBody obj) { /* TODO */ return Vector3.Zero; }
+    public override void ApplyDamping(BulletBody pBody, float timeStep)
+    {
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
+        body.ApplyDamping(timeStep);
+    }
 
-    public override void SetLinearFactor(BulletBody obj, Vector3 factor) { /* TODO */ }
+    public override Vector3 GetLinearFactor(BulletBody pBody)
+    {
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
+        IndexedVector3 linearFactor = body.GetLinearFactor();
+        return new Vector3(linearFactor.X, linearFactor.Y, linearFactor.Z);
+    }
 
-    public override void SetCenterOfMassByPosRot(BulletBody obj, Vector3 pos, Quaternion rot) { /* TODO */ }
+    public override void SetLinearFactor(BulletBody pBody, Vector3 factor)
+    {
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
+        body.SetLinearFactor(new IndexedVector3(factor.X, factor.Y, factor.Z));
+    }
+
+    public override void SetCenterOfMassByPosRot(BulletBody pBody, Vector3 pos, Quaternion rot)
+    {
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
+        IndexedQuaternion quat = new IndexedQuaternion(rot.X, rot.Y, rot.Z,rot.W);
+        IndexedMatrix mat = IndexedMatrix.CreateFromQuaternion(quat);
+        mat._origin = new IndexedVector3(pos.X, pos.Y, pos.Z);
+        body.SetCenterOfMassTransform( ref mat);
+        /* TODO: double check this */
+    }
 
     //BulletSimAPI.ApplyCentralForce(PhysBody.ptr, fSum);
     public override void ApplyCentralForce(BulletBody pBody, Vector3 pfSum)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 fSum = new IndexedVector3(pfSum.X, pfSum.Y, pfSum.Z);
         body.ApplyCentralForce(ref fSum);
     }
     public override void ApplyCentralImpulse(BulletBody pBody, Vector3 pfSum)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 fSum = new IndexedVector3(pfSum.X, pfSum.Y, pfSum.Z);
         body.ApplyCentralImpulse(ref fSum);
     }
     public override void ApplyTorque(BulletBody pBody, Vector3 pfSum)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 fSum = new IndexedVector3(pfSum.X, pfSum.Y, pfSum.Z);
         body.ApplyTorque(ref fSum);
     }
     public override void ApplyTorqueImpulse(BulletBody pBody, Vector3 pfSum)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
+        RigidBody body = (pBody as BulletBodyXNA).rigidBody;
         IndexedVector3 fSum = new IndexedVector3(pfSum.X, pfSum.Y, pfSum.Z);
         body.ApplyTorqueImpulse(ref fSum);
     }
 
-    public override void DestroyObject(BulletWorld p, BulletBody p_2)
+    public override void DestroyObject(BulletWorld pWorld, BulletBody pBody)
     {
-        //TODO:
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        CollisionObject co = (pBody as BulletBodyXNA).rigidBody;
+        RigidBody bo = co as RigidBody;
+        if (bo == null)
+        {
+            
+            if (world.IsInWorld(co))
+            {
+                world.RemoveCollisionObject(co);
+            }
+        }
+        else
+        {
+            
+            if (world.IsInWorld(bo))
+            {
+                world.RemoveRigidBody(bo);
+            }
+        }
+       
     }
 
     public override void Shutdown(BulletWorld pWorld)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
         world.Cleanup();
     }
 
-    public override BulletShape DuplicateCollisionShape(BulletWorld sim, BulletShape srcShape, uint id)
+    public override BulletShape DuplicateCollisionShape(BulletWorld pWorld, BulletShape pShape, uint id)
     {
-        return null;
+        CollisionShape shape1 = (pShape as BulletShapeXNA).shape;
+
+        // TODO:  Turn this from a reference copy to a Value Copy.
+        BulletShapeXNA shape2 = new BulletShapeXNA(shape1, BSPhysicsShapeType.SHAPE_UNKNOWN);
+        
+        return shape2;
     }
 
-    public override bool DeleteCollisionShape(BulletWorld p, BulletShape p_2)
+    public override bool DeleteCollisionShape(BulletWorld pWorld, BulletShape pShape)
     {
         //TODO:
         return false;
@@ -802,17 +914,40 @@ private sealed class BulletConstraintXNA : BulletConstraint
                
     public override BulletBody CreateBodyFromShape(BulletWorld pWorld, BulletShape pShape, uint pLocalID, Vector3 pRawPosition, Quaternion pRawOrientation)
     {
-        CollisionWorld world = ((BulletWorldXNA)pWorld).world;
+        CollisionWorld world = (pWorld as BulletWorldXNA).world;
         IndexedMatrix mat =
             IndexedMatrix.CreateFromQuaternion(new IndexedQuaternion(pRawOrientation.X, pRawOrientation.Y,
                                                                      pRawOrientation.Z, pRawOrientation.W));
         mat._origin = new IndexedVector3(pRawPosition.X, pRawPosition.Y, pRawPosition.Z);
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         //UpdateSingleAabb(world, shape);
         // TODO: Feed Update array into null
-        RigidBody body = new RigidBody(0,new SimMotionState(world,pLocalID,mat,null),shape,IndexedVector3.Zero);
-        
+        SimMotionState motionState = new SimMotionState(world, pLocalID, mat, null);
+        RigidBody body = new RigidBody(0,motionState,shape,IndexedVector3.Zero);
+        RigidBodyConstructionInfo constructionInfo = new RigidBodyConstructionInfo(0, new SimMotionState(world, pLocalID, mat, null),shape,IndexedVector3.Zero)
+                                                         {
+                                                             m_mass = 0
+                                                         };
+        /*
+            m_mass = mass;
+			m_motionState =motionState;
+			m_collisionShape = collisionShape;
+			m_localInertia = localInertia;
+			m_linearDamping = 0f;
+			m_angularDamping = 0f;
+			m_friction = 0.5f;
+			m_restitution = 0f;
+			m_linearSleepingThreshold = 0.8f;
+			m_angularSleepingThreshold = 1f;
+			m_additionalDamping = false;
+			m_additionalDampingFactor = 0.005f;
+			m_additionalLinearDampingThresholdSqr = 0.01f;
+			m_additionalAngularDampingThresholdSqr = 0.01f;
+			m_additionalAngularDampingFactor = 0.01f;
+            m_startWorldTransform = IndexedMatrix.Identity;
+        */
         body.SetUserPointer(pLocalID);
+        
         return new BulletBodyXNA(pLocalID, body);
     }
 
@@ -825,7 +960,7 @@ private sealed class BulletConstraintXNA : BulletConstraint
                                                                      pRawOrientation.Z, pRawOrientation.W));
         mat._origin = new IndexedVector3(pRawPosition.X, pRawPosition.Y, pRawPosition.Z);
 
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
 
         // TODO: Feed Update array into null
         RigidBody body = new RigidBody(0, new DefaultMotionState( mat, IndexedMatrix.Identity), shape, IndexedVector3.Zero);
@@ -834,21 +969,43 @@ private sealed class BulletConstraintXNA : BulletConstraint
         return new BulletBodyXNA(pLocalID, body);
     }
     //(m_mapInfo.terrainBody.ptr, CollisionFlags.CF_STATIC_OBJECT);
-    public override CollisionFlags SetCollisionFlags(BulletBody pBody, CollisionFlags collisionFlags)
+    public override CollisionFlags SetCollisionFlags(BulletBody pCollisionObject, CollisionFlags collisionFlags)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        body.SetCollisionFlags((BulletXNA.BulletCollision.CollisionFlags) (uint) collisionFlags);
-        return (CollisionFlags)body.GetCollisionFlags();
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        collisionObject.SetCollisionFlags((BulletXNA.BulletCollision.CollisionFlags) (uint) collisionFlags);
+        return (CollisionFlags)collisionObject.GetCollisionFlags();
     }
 
-    public override Vector3 GetAnisotripicFriction(BulletConstraint pconstrain) { /* TODO */ return Vector3.Zero; }
+    public override Vector3 GetAnisotripicFriction(BulletConstraint pconstrain)
+    {
+
+        /* TODO */ 
+        return Vector3.Zero;
+    }
     public override Vector3 SetAnisotripicFriction(BulletConstraint pconstrain, Vector3 frict) { /* TODO */ return Vector3.Zero; }
     public override bool HasAnisotripicFriction(BulletConstraint pconstrain) { /* TODO */ return false; }
     public override float GetContactProcessingThreshold(BulletBody pBody) { /* TODO */ return 0f; }
-    public override bool IsStaticObject(BulletBody pBody) { /* TODO */ return false; }
-    public override bool IsKinematicObject(BulletBody pBody) { /* TODO */ return false; }
-    public override bool IsStaticOrKinematicObject(BulletBody pBody) { /* TODO */ return false; }
-    public override bool HasContactResponse(BulletBody pBody) { /* TODO */ return false; }
+    public override bool IsStaticObject(BulletBody pCollisionObject)
+    {
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        return collisionObject.IsStaticObject();
+        
+    }
+    public override bool IsKinematicObject(BulletBody pCollisionObject)
+    {
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        return collisionObject.IsKinematicObject();
+    }
+    public override bool IsStaticOrKinematicObject(BulletBody pCollisionObject)
+    {
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        return collisionObject.IsStaticOrKinematicObject();
+    }
+    public override bool HasContactResponse(BulletBody pCollisionObject)
+    {
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        return collisionObject.HasContactResponse();
+    }
     public override int GetActivationState(BulletBody pBody) { /* TODO */ return 0; }
     public override void SetActivationState(BulletBody pBody, int state) { /* TODO */ }
     public override float GetDeactivationTime(BulletBody pBody) { /* TODO */ return 0f; }
@@ -859,15 +1016,15 @@ private sealed class BulletConstraintXNA : BulletConstraint
     public override float GetHitFraction(BulletBody pBody) { /* TODO */ return 0f; }
 
     //(m_mapInfo.terrainBody.ptr, PhysicsScene.Params.terrainHitFraction);
-    public override void SetHitFraction(BulletBody pBody, float pHitFraction)
+    public override void SetHitFraction(BulletBody pCollisionObject, float pHitFraction)
     {
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        body.SetHitFraction(pHitFraction);
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        collisionObject.SetHitFraction(pHitFraction);
     }
     //BuildCapsuleShape(physicsScene.World.ptr, 1f, 1f, prim.Scale);
     public override BulletShape BuildCapsuleShape(BulletWorld pWorld, float pRadius, float pHeight, Vector3 pScale)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
         IndexedVector3 scale = new IndexedVector3(pScale.X, pScale.Y, pScale.Z);
         CapsuleShapeZ capsuleShapeZ = new CapsuleShapeZ(pRadius, pHeight);
         capsuleShapeZ.SetMargin(world.WorldSettings.Params.collisionMargin);
@@ -881,14 +1038,24 @@ private sealed class BulletConstraintXNA : BulletConstraint
                                             int maxUpdates, ref EntityProperties[] updateArray
                                             )
     {
+
+        m_updateArray = updateArray;
+        m_collisionArray = collisionArray;
         /* TODO */
-        return new BulletWorldXNA(1, null, null);
+        ConfigurationParameters[] configparms = new ConfigurationParameters[1];
+        configparms[0] = parms;
+        Vector3 worldExtent = new Vector3(Constants.RegionSize, Constants.RegionSize, Constants.RegionHeight);
+        m_maxCollisions = maxCollisions;
+        m_maxUpdatesPerFrame = maxUpdates;
+
+
+        return new BulletWorldXNA(1, PhysicsScene, BSAPIXNA.Initialize2(worldExtent, configparms, maxCollisions, ref collisionArray, maxUpdates, ref updateArray, null));
     }
 
-    private static object Initialize2(Vector3 worldExtent, 
+    private static DiscreteDynamicsWorld Initialize2(Vector3 worldExtent, 
                         ConfigurationParameters[] o,
-                        int mMaxCollisionsPerFrame, ref List<BulletXNA.CollisionDesc> collisionArray,
-                        int mMaxUpdatesPerFrame, ref List<BulletXNA.EntityProperties> updateArray, 
+                        int mMaxCollisionsPerFrame, ref CollisionDesc[] collisionArray,
+                        int mMaxUpdatesPerFrame, ref EntityProperties[] updateArray, 
                         object mDebugLogCallbackHandle)
     {
         CollisionWorld.WorldData.ParamData p = new CollisionWorld.WorldData.ParamData();
@@ -968,8 +1135,13 @@ private sealed class BulletConstraintXNA : BulletConstraint
         SequentialImpulseConstraintSolver m_solver = new SequentialImpulseConstraintSolver();
 
         DiscreteDynamicsWorld world = new DiscreteDynamicsWorld(m_dispatcher, m_broadphase, m_solver, cci);
-        world.UpdatedObjects = updateArray;
-        world.UpdatedCollisions = collisionArray;
+        
+        
+        world.UpdatedObjects = BSAPIXNA.GetBulletXNAEntityStruct(BSAPIXNA.BulletSimEntityStructToByteArray(updateArray, updateArray.Length));
+        world.UpdatedCollisions = BSAPIXNA.GetBulletXNACollisionStruct(BSAPIXNA.BulletSimCollisionStructToByteArray(collisionArray, collisionArray.Length));
+        world.LastCollisionDesc = 0;
+        world.LastEntityProperty = 0;
+
         world.WorldSettings.Params = p;
         world.SetForceUpdateAllAabbs(p.shouldForceUpdateAllAabbs != 0);
         world.GetSolverInfo().m_solverMode = SolverMode.SOLVER_USE_WARMSTARTING | SolverMode.SOLVER_SIMD;
@@ -1003,7 +1175,7 @@ private sealed class BulletConstraintXNA : BulletConstraint
         world.GetSolverInfo().m_restingContactRestitutionThreshold = 2;
         world.SetForceUpdateAllAabbs(true);
 
-
+        //BSParam.TerrainImplementation = 0;
         world.SetGravity(new IndexedVector3(0,0,p.gravity));
 
         return world;
@@ -1011,7 +1183,7 @@ private sealed class BulletConstraintXNA : BulletConstraint
     //m_constraint.ptr, ConstraintParams.BT_CONSTRAINT_STOP_CFM, cfm, ConstraintParamAxis.AXIS_ALL
     public override bool SetConstraintParam(BulletConstraint pConstraint, ConstraintParams paramIndex, float paramvalue, ConstraintParamAxis axis)
     {
-        Generic6DofConstraint constrain = ((BulletConstraintXNA)pConstraint).constrain as Generic6DofConstraint;
+        Generic6DofConstraint constrain = (pConstraint as BulletConstraintXNA).constrain as Generic6DofConstraint;
         if (axis == ConstraintParamAxis.AXIS_LINEAR_ALL || axis == ConstraintParamAxis.AXIS_ALL)
         {
             constrain.SetParam((BulletXNA.BulletDynamics.ConstraintParams) (int) paramIndex, paramvalue, 0);
@@ -1034,7 +1206,8 @@ private sealed class BulletConstraintXNA : BulletConstraint
     public override bool PushUpdate(BulletBody pCollisionObject)
     {
         bool ret = false;
-        RigidBody rb = ((BulletBodyXNA)pCollisionObject).rigidBody;
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        RigidBody rb = collisionObject as RigidBody;
         if (rb != null)
         {
             SimMotionState sms = rb.GetMotionState() as SimMotionState;
@@ -1052,57 +1225,57 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override float GetAngularMotionDisc(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         return shape.GetAngularMotionDisc();
     }
     public override float GetContactBreakingThreshold(BulletShape pShape, float defaultFactor)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         return shape.GetContactBreakingThreshold(defaultFactor);
     }
     public override bool IsCompound(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         return shape.IsCompound();
     }
     public override bool IsSoftBody(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         return shape.IsSoftBody();
     }
     public override bool IsPolyhedral(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         return shape.IsPolyhedral();
     }
     public override bool IsConvex2d(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         return shape.IsConvex2d();
     }
     public override bool IsConvex(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         return shape.IsConvex();
     }
     public override bool IsNonMoving(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         return shape.IsNonMoving();
     }
     public override bool IsConcave(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         return shape.IsConcave();
     }
     public override bool IsInfinite(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         return shape.IsInfinite();
     }
     public override bool IsNativeShape(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         bool ret;
         switch (shape.GetShapeType())
         {
@@ -1119,38 +1292,53 @@ private sealed class BulletConstraintXNA : BulletConstraint
         return ret;
     }
 
-    public override void SetShapeCollisionMargin(BulletShape shape, float margin) { /* TODO */ }
+    public override void SetShapeCollisionMargin(BulletShape pShape, float pMargin)
+    {
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
+        shape.SetMargin(pMargin);
+    }
 
     //sim.ptr, shape.ptr,prim.LocalID, prim.RawPosition, prim.RawOrientation
     public override BulletBody CreateGhostFromShape(BulletWorld pWorld, BulletShape pShape, uint pLocalID, Vector3 pRawPosition, Quaternion pRawOrientation)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
         IndexedMatrix bodyTransform = new IndexedMatrix();
         bodyTransform._origin = new IndexedVector3(pRawPosition.X, pRawPosition.Y, pRawPosition.Z);
         bodyTransform.SetRotation(new IndexedQuaternion(pRawOrientation.X,pRawOrientation.Y,pRawOrientation.Z,pRawOrientation.W));
         GhostObject gObj = new PairCachingGhostObject();
         gObj.SetWorldTransform(bodyTransform);
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         gObj.SetCollisionShape(shape);
         gObj.SetUserPointer(pLocalID);
         // TODO: Add to Special CollisionObjects!
         return new BulletBodyXNA(pLocalID, gObj);
     }
 
-    public override void SetCollisionShape(BulletWorld pWorld, BulletBody pObj, BulletShape pShape)
+    public override void SetCollisionShape(BulletWorld pWorld, BulletBody pCollisionObject, BulletShape pShape)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
-        CollisionObject obj = ((BulletBodyXNA)pObj).body;
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
-        obj.SetCollisionShape(shape);
-
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).body;
+        if (pShape == null)
+        {
+            collisionObject.SetCollisionShape(new EmptyShape());
+        }
+        else
+        {
+            CollisionShape shape = (pShape as BulletShapeXNA).shape;
+            collisionObject.SetCollisionShape(shape);
+        }
+    }
+    public override BulletShape GetCollisionShape(BulletBody pCollisionObject)
+    {
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        CollisionShape shape = collisionObject.GetCollisionShape();
+        return new BulletShapeXNA(shape,BSPhysicsShapeType.SHAPE_UNKNOWN);
     }
-    public override BulletShape GetCollisionShape(BulletBody obj) { /* TODO */ return null; }
 
     //(PhysicsScene.World.ptr, nativeShapeData)
     public override BulletShape BuildNativeShape(BulletWorld pWorld, ShapeData pShapeData)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
         CollisionShape shape = null;
         switch (pShapeData.Type)
         {
@@ -1185,15 +1373,15 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override int GetNumberOfCompoundChildren(BulletShape pCompoundShape)
     {
-        CompoundShape compoundshape = ((BulletShapeXNA)pCompoundShape).shape as CompoundShape;
+        CompoundShape compoundshape = (pCompoundShape as BulletShapeXNA).shape as CompoundShape;
         return compoundshape.GetNumChildShapes();
     }
     //LinksetRoot.PhysShape.ptr, newShape.ptr, displacementPos, displacementRot
     public override void AddChildShapeToCompoundShape(BulletShape pCShape, BulletShape paddShape, Vector3 displacementPos, Quaternion displacementRot)
     {
         IndexedMatrix relativeTransform = new IndexedMatrix();
-        CompoundShape compoundshape = ((BulletShapeXNA)pCShape).shape as CompoundShape;
-        CollisionShape addshape = ((BulletShapeXNA)paddShape).shape;
+        CompoundShape compoundshape = (pCShape as BulletShapeXNA).shape as CompoundShape;
+        CollisionShape addshape = (paddShape as BulletShapeXNA).shape;
 
         relativeTransform._origin = new IndexedVector3(displacementPos.X, displacementPos.Y, displacementPos.Z);
         relativeTransform.SetRotation(new IndexedQuaternion(displacementRot.X,displacementRot.Y,displacementRot.Z,displacementRot.W));
@@ -1203,7 +1391,7 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override BulletShape RemoveChildShapeFromCompoundShapeIndex(BulletShape pCShape, int pii)
     {
-        CompoundShape compoundshape = ((BulletShapeXNA)pCShape).shape as CompoundShape;
+        CompoundShape compoundshape = (pCShape as BulletShapeXNA).shape as CompoundShape;
         CollisionShape ret = null;
         ret = compoundshape.GetChildShape(pii);
         compoundshape.RemoveChildShapeByIndex(pii);
@@ -1222,12 +1410,12 @@ private sealed class BulletConstraintXNA : BulletConstraint
         return new BulletShapeXNA(m_planeshape, BSPhysicsShapeType.SHAPE_GROUNDPLANE);
     }
 
-    public override BulletConstraint CreateHingeConstraint(BulletWorld pWorld, BulletBody pBody1, BulletBody ppBody2, Vector3 ppivotInA, Vector3 ppivotInB, Vector3 paxisInA, Vector3 paxisInB, bool puseLinearReferenceFrameA, bool pdisableCollisionsBetweenLinkedBodies)
+    public override BulletConstraint CreateHingeConstraint(BulletWorld pWorld, BulletBody pBody1, BulletBody pBody2, Vector3 ppivotInA, Vector3 ppivotInB, Vector3 paxisInA, Vector3 paxisInB, bool puseLinearReferenceFrameA, bool pdisableCollisionsBetweenLinkedBodies)
     {
         HingeConstraint constrain = null;
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
-        RigidBody rb1 = ((BulletBodyXNA)pBody1).rigidBody;
-        RigidBody rb2 = ((BulletBodyXNA)ppBody2).rigidBody;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        RigidBody rb1 = (pBody1 as BulletBodyXNA).rigidBody;
+        RigidBody rb2 = (pBody2 as BulletBodyXNA).rigidBody;
         if (rb1 != null && rb2 != null)
         {
             IndexedVector3 pivotInA = new IndexedVector3(ppivotInA.X, ppivotInA.Y, ppivotInA.Z);
@@ -1241,7 +1429,7 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override BulletShape CreateHullShape(BulletWorld pWorld, int pHullCount, float[] pConvHulls)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
         CompoundShape compoundshape = new CompoundShape(false);
         
         compoundshape.SetMargin(world.WorldSettings.Params.collisionMargin);
@@ -1271,7 +1459,11 @@ private sealed class BulletConstraintXNA : BulletConstraint
         return new BulletShapeXNA(compoundshape, BSPhysicsShapeType.SHAPE_HULL);
     }
 
-    public override BulletShape BuildHullShapeFromMesh(BulletWorld world, BulletShape meshShape) { /* TODO */ return null; }
+    public override BulletShape BuildHullShapeFromMesh(BulletWorld world, BulletShape meshShape)
+    {
+        /* TODO */ return null;
+
+    }
 
     public override BulletShape CreateMeshShape(BulletWorld pWorld, int pIndicesCount, int[] indices, int pVerticesCount, float[] verticesAsFloats)
     {
@@ -1286,7 +1478,7 @@ private sealed class BulletConstraintXNA : BulletConstraint
         ObjectArray<int> indicesarr = new ObjectArray<int>(indices);
         ObjectArray<float> vertices = new ObjectArray<float>(verticesAsFloats);
         DumpRaw(indicesarr,vertices,pIndicesCount,pVerticesCount);
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
         IndexedMesh mesh = new IndexedMesh();
         mesh.m_indexType = PHY_ScalarType.PHY_INTEGER;
         mesh.m_numTriangles = pIndicesCount/3;
@@ -1402,7 +1594,7 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override bool TranslationalLimitMotor(BulletConstraint pConstraint, float ponOff, float targetVelocity, float maxMotorForce)
     {
-        TypedConstraint tconstrain = ((BulletConstraintXNA)pConstraint).constrain;
+        TypedConstraint tconstrain = (pConstraint as BulletConstraintXNA).constrain;
         bool onOff = ponOff != 0;
         bool ret = false;
 
@@ -1428,47 +1620,45 @@ private sealed class BulletConstraintXNA : BulletConstraint
         /* TODO */
         updatedEntityCount = 0;
         collidersCount = 0;
-        return 1;
+        
+
+        int ret = PhysicsStep2(world,timeStep,maxSubSteps,fixedTimeStep,out updatedEntityCount,out world.physicsScene.m_updateArray, out collidersCount, out world.physicsScene.m_collisionArray);
+
+        return ret;
     }
 
     private int PhysicsStep2(BulletWorld pWorld, float timeStep, int m_maxSubSteps, float m_fixedTimeStep, 
-                    out int updatedEntityCount, out List<BulletXNA.EntityProperties> updatedEntities, 
-                    out int collidersCount, out List<BulletXNA.CollisionDesc>colliders)
+                    out int updatedEntityCount, out EntityProperties[] updatedEntities,
+                    out int collidersCount, out CollisionDesc[] colliders)
     {
         int epic = PhysicsStepint(pWorld, timeStep, m_maxSubSteps, m_fixedTimeStep, out updatedEntityCount, out updatedEntities,
-                                out collidersCount, out colliders);
+                                out collidersCount, out colliders, m_maxCollisions, m_maxUpdatesPerFrame);
         return epic;
     }
 
-    private static int PhysicsStepint(BulletWorld pWorld,float timeStep, int m_maxSubSteps, float m_fixedTimeStep, out int updatedEntityCount, out List<BulletXNA.EntityProperties> updatedEntities, out int collidersCount, out List<BulletXNA.CollisionDesc> colliders)
+    private static int PhysicsStepint(BulletWorld pWorld,float timeStep, int m_maxSubSteps, float m_fixedTimeStep, out int updatedEntityCount, 
+        out  EntityProperties[] updatedEntities, out int collidersCount, out CollisionDesc[] colliders, int maxCollisions, int maxUpdates)
     {
         int numSimSteps = 0;
-      
 
-        //if (updatedEntities is null)
-        //    updatedEntities = new List<BulletXNA.EntityProperties>();
-
-        //if (colliders is null)
-        //    colliders = new List<BulletXNA.CollisionDesc>();
+        updatedEntityCount = 0;
+        collidersCount = 0;
         
 
         if (pWorld is BulletWorldXNA)
         {
-            DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
+            DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
 
+            world.LastCollisionDesc = 0;
+            world.LastEntityProperty = 0;
+            world.UpdatedObjects = new BulletXNA.EntityProperties[maxUpdates];
+            world.UpdatedCollisions = new BulletXNA.CollisionDesc[maxCollisions];
             numSimSteps = world.StepSimulation(timeStep, m_maxSubSteps, m_fixedTimeStep);
             int updates = 0;
 
-            updatedEntityCount = world.UpdatedObjects.Count;
-            updatedEntities = new List<BulletXNA.EntityProperties>(world.UpdatedObjects);
-            updatedEntityCount = updatedEntities.Count;
-            world.UpdatedObjects.Clear();
+            
             
 
-            collidersCount = world.UpdatedCollisions.Count;
-            colliders = new List<BulletXNA.CollisionDesc>(world.UpdatedCollisions);
-
-            world.UpdatedCollisions.Clear();
             m_collisionsThisFrame = 0;
             int numManifolds = world.GetDispatcher().GetNumManifolds();
             for (int j = 0; j < numManifolds; j++)
@@ -1493,16 +1683,31 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
             }
 
+            updatedEntityCount = world.LastEntityProperty;
+            updatedEntities = GetBulletSimEntityStruct(BulletXNAEntityStructToByteArray(world.UpdatedObjects, world.LastEntityProperty));
+
+
+
+
+            collidersCount = world.LastCollisionDesc;
+            colliders =
+                GetBulletSimCollisionStruct(BulletXNACollisionStructToByteArray(world.UpdatedCollisions, world.LastCollisionDesc));//new List<BulletXNA.CollisionDesc>(world.UpdatedCollisions);
 
         }
         else
         {
             //if (updatedEntities is null)
-            updatedEntities = new List<BulletXNA.EntityProperties>();
-            updatedEntityCount = 0;
+            //updatedEntities = new List<BulletXNA.EntityProperties>();
+            //updatedEntityCount = 0;
             //if (colliders is null)
-            colliders = new List<BulletXNA.CollisionDesc>();
-            collidersCount = 0;
+            //colliders = new List<BulletXNA.CollisionDesc>();
+            //collidersCount = 0;
+           
+            updatedEntities = new EntityProperties[0];
+
+            
+            colliders = new CollisionDesc[0];
+        
         }
         return numSimSteps;
     }
@@ -1535,22 +1740,23 @@ private sealed class BulletConstraintXNA : BulletConstraint
                                                 point = contact,
                                                 normal = contactNormal
                                             };
-        world.UpdatedCollisions.Add(cDesc);
+        if (world.LastCollisionDesc < world.UpdatedCollisions.Length)
+            world.UpdatedCollisions[world.LastCollisionDesc++] = (cDesc);
         m_collisionsThisFrame++;
 
 
     }
-    private static EntityProperties GetDebugProperties(BulletWorld pWorld, BulletBody pBody)
+    private static EntityProperties GetDebugProperties(BulletWorld pWorld, BulletBody pCollisionObject)
     {
         EntityProperties ent = new EntityProperties();
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
-        RigidBody body = ((BulletBodyXNA)pBody).rigidBody;
-        IndexedMatrix transform = body.GetWorldTransform();
-        IndexedVector3 LinearVelocity = body.GetInterpolationLinearVelocity();
-        IndexedVector3 AngularVelocity = body.GetInterpolationAngularVelocity();
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
+        CollisionObject collisionObject = (pCollisionObject as BulletBodyXNA).rigidBody;
+        IndexedMatrix transform = collisionObject.GetWorldTransform();
+        IndexedVector3 LinearVelocity = collisionObject.GetInterpolationLinearVelocity();
+        IndexedVector3 AngularVelocity = collisionObject.GetInterpolationAngularVelocity();
         IndexedQuaternion rotation = transform.GetRotation();
         ent.Acceleration = Vector3.Zero;
-        ent.ID = (uint)body.GetUserPointer();
+        ent.ID = (uint)collisionObject.GetUserPointer();
         ent.Position = new Vector3(transform._origin.X,transform._origin.Y,transform._origin.Z);
         ent.Rotation = new Quaternion(rotation.X,rotation.Y,rotation.Z,rotation.W);
         ent.Velocity = new Vector3(LinearVelocity.X, LinearVelocity.Y, LinearVelocity.Z);
@@ -1562,19 +1768,19 @@ private sealed class BulletConstraintXNA : BulletConstraint
 
     public override Vector3 GetLocalScaling(BulletShape pShape)
     {
-        CollisionShape shape = ((BulletShapeXNA)pShape).shape;
+        CollisionShape shape = (pShape as BulletShapeXNA).shape;
         IndexedVector3 scale = shape.GetLocalScaling();
         return new Vector3(scale.X,scale.Y,scale.Z);
     }
 
     public bool RayCastGround(BulletWorld pWorld, Vector3 _RayOrigin, float pRayHeight, BulletBody NotMe)
     {
-        DiscreteDynamicsWorld world = ((BulletWorldXNA)pWorld).world;
+        DiscreteDynamicsWorld world = (pWorld as BulletWorldXNA).world;
         if (world != null)
         {
             if (NotMe is BulletBodyXNA && NotMe.HasPhysicalBody)
             {
-                CollisionObject AvoidBody = ((BulletBodyXNA)NotMe).body;
+                CollisionObject AvoidBody = (NotMe as BulletBodyXNA).body;
                 
                 IndexedVector3 rOrigin = new IndexedVector3(_RayOrigin.X, _RayOrigin.Y, _RayOrigin.Z);
                 IndexedVector3 rEnd = new IndexedVector3(_RayOrigin.X, _RayOrigin.Y, _RayOrigin.Z - pRayHeight);
@@ -1594,5 +1800,160 @@ private sealed class BulletConstraintXNA : BulletConstraint
         }
         return false;
     }
+    
+    public static unsafe BulletXNA.CollisionDesc[] GetBulletXNACollisionStruct(byte[] buffer)
+    {
+        int count = buffer.Length/sizeof (BulletXNA.CollisionDesc);
+        BulletXNA.CollisionDesc[] result = new BulletXNA.CollisionDesc[count];
+        BulletXNA.CollisionDesc* ptr;
+        fixed (byte* localBytes = new byte[buffer.Length])
+        {
+            for (int i = 0; i < buffer.Length; i++)
+            {
+                localBytes[i] = buffer[i];
+            }
+            for (int i=0;i<count;i++)
+            {
+                ptr = (BulletXNA.CollisionDesc*) (localBytes + sizeof (BulletXNA.CollisionDesc)*i);
+                result[i] = new BulletXNA.CollisionDesc();
+                result[i] = *ptr;
+            }
+        }
+        return result;
+    }
+
+    public static unsafe CollisionDesc[] GetBulletSimCollisionStruct(byte[] buffer)
+    {
+        int count = buffer.Length / sizeof(CollisionDesc);
+        CollisionDesc[] result = new CollisionDesc[count];
+        CollisionDesc* ptr;
+        fixed (byte* localBytes = new byte[buffer.Length])
+        {
+            for (int i = 0; i < buffer.Length; i++)
+            {
+                localBytes[i] = buffer[i];
+            }
+            for (int i = 0; i < count; i++)
+            {
+                ptr = (CollisionDesc*)(localBytes + sizeof(CollisionDesc) * i);
+                result[i] = new CollisionDesc();
+                result[i] = *ptr;
+            }
+        }
+        return result;
+    }
+    public static unsafe byte[] BulletSimCollisionStructToByteArray(CollisionDesc[] CollisionDescArray, int count)
+    {
+        int arrayLength = CollisionDescArray.Length > count ? count : CollisionDescArray.Length;
+        byte[] byteArray = new byte[sizeof(CollisionDesc) * arrayLength];
+        fixed (CollisionDesc* floatPointer = CollisionDescArray)
+        {
+            fixed (byte* bytePointer = byteArray)
+            {
+                CollisionDesc* read = floatPointer;
+                CollisionDesc* write = (CollisionDesc*)bytePointer;
+                for (int i = 0; i < arrayLength; i++)
+                {
+                    *write++ = *read++;
+                }
+            }
+        }
+        return byteArray;
+    }
+    public static unsafe byte[] BulletXNACollisionStructToByteArray(BulletXNA.CollisionDesc[] CollisionDescArray, int count)
+    {
+        int arrayLength = CollisionDescArray.Length > count ? count : CollisionDescArray.Length;
+        byte[] byteArray = new byte[sizeof(BulletXNA.CollisionDesc) * arrayLength];
+        fixed (BulletXNA.CollisionDesc* floatPointer = CollisionDescArray)
+        {
+            fixed (byte* bytePointer = byteArray)
+            {
+                BulletXNA.CollisionDesc* read = floatPointer;
+                BulletXNA.CollisionDesc* write = (BulletXNA.CollisionDesc*)bytePointer;
+                for (int i = 0; i < arrayLength; i++)
+                {
+                    *write++ = *read++;
+                }
+            }
+        }
+        return byteArray;
+    }
+    public static unsafe BulletXNA.EntityProperties[] GetBulletXNAEntityStruct(byte[] buffer)
+    {
+        int count = buffer.Length / sizeof(BulletXNA.EntityProperties);
+        BulletXNA.EntityProperties[] result = new BulletXNA.EntityProperties[count];
+        BulletXNA.EntityProperties* ptr;
+        fixed (byte* localBytes = new byte[buffer.Length])
+        {
+            for (int i = 0; i < buffer.Length; i++)
+            {
+                localBytes[i] = buffer[i];
+            }
+            for (int i = 0; i < count; i++)
+            {
+                ptr = (BulletXNA.EntityProperties*)(localBytes + sizeof(BulletXNA.EntityProperties) * i);
+                result[i] = new BulletXNA.EntityProperties();
+                result[i] = *ptr;
+            }
+        }
+        return result;
+    }
+
+    public static unsafe EntityProperties[] GetBulletSimEntityStruct(byte[] buffer)
+    {
+        int count = buffer.Length / sizeof(EntityProperties);
+        EntityProperties[] result = new EntityProperties[count];
+        EntityProperties* ptr;
+        fixed (byte* localBytes = new byte[buffer.Length])
+        {
+            for (int i = 0; i < buffer.Length; i++)
+            {
+                localBytes[i] = buffer[i];
+            }
+            for (int i = 0; i < count; i++)
+            {
+                ptr = (EntityProperties*)(localBytes + sizeof(EntityProperties) * i);
+                result[i] = new EntityProperties();
+                result[i] = *ptr;
+            }
+        }
+        return result;
+    }
+    public static unsafe byte[] BulletSimEntityStructToByteArray(EntityProperties[] CollisionDescArray, int count)
+    {
+        int arrayLength = CollisionDescArray.Length > count ? count : CollisionDescArray.Length;
+        byte[] byteArray = new byte[sizeof(EntityProperties) * arrayLength];
+        fixed (EntityProperties* floatPointer = CollisionDescArray)
+        {
+            fixed (byte* bytePointer = byteArray)
+            {
+                EntityProperties* read = floatPointer;
+                EntityProperties* write = (EntityProperties*)bytePointer;
+                for (int i = 0; i < arrayLength; i++)
+                {
+                    *write++ = *read++;
+                }
+            }
+        }
+        return byteArray;
+    }
+    public static unsafe byte[] BulletXNAEntityStructToByteArray(BulletXNA.EntityProperties[] CollisionDescArray, int count)
+    {
+        int arrayLength = CollisionDescArray.Length > count ? count : CollisionDescArray.Length;
+        byte[] byteArray = new byte[sizeof(BulletXNA.EntityProperties) * arrayLength];
+        fixed (BulletXNA.EntityProperties* floatPointer = CollisionDescArray)
+        {
+            fixed (byte* bytePointer = byteArray)
+            {
+                BulletXNA.EntityProperties* read = floatPointer;
+                BulletXNA.EntityProperties* write = (BulletXNA.EntityProperties*)bytePointer;
+                for (int i = 0; i < arrayLength; i++)
+                {
+                    *write++ = *read++;
+                }
+            }
+        }
+        return byteArray;
+    }
 }
 }
diff --git a/bin/BulletXNA.dll b/bin/BulletXNA.dll
index 1e3f04253f..5e69b2e28b 100644
Binary files a/bin/BulletXNA.dll and b/bin/BulletXNA.dll differ
diff --git a/bin/BulletXNA.pdb b/bin/BulletXNA.pdb
index 4b83b83f28..3d4906f44d 100644
Binary files a/bin/BulletXNA.pdb and b/bin/BulletXNA.pdb differ
diff --git a/bin/OpenSimDefaults.ini b/bin/OpenSimDefaults.ini
index 54b88b4875..889865b618 100644
--- a/bin/OpenSimDefaults.ini
+++ b/bin/OpenSimDefaults.ini
@@ -908,6 +908,19 @@
 
 [BulletSim]
     ; World parameters
+
+    ; There are two bullet physics libraries, bulletunmanaged is the default and is a native c++ dll
+    ; bulletxna is a managed C# dll.  They have comparible functionality..   the c++ is much faster.
+
+    BulletEngine = "bulletunmanaged"
+    ; BulletEngine = "bulletxna"
+
+    ; Terrain Implementation {1|0} 0 for HeightField, 1 for Mesh terrain.  If you're using the bulletxna engine, 
+    ;  you will want to switch to the heightfield option
+
+    TerrainImplementation = 1
+    ; TerrainImplementation = 0
+
     DefaultFriction = 0.20
     DefaultDensity = 10.000006836
     DefaultRestitution = 0.0
@@ -959,6 +972,7 @@
     PhysicsLoggingEnabled = False
     PhysicsLoggingDir = "."
     VehicleLoggingEnabled = False
+    
 
 [RemoteAdmin]
     enabled = false
diff --git a/prebuild.xml b/prebuild.xml
index bb9b7d6de4..37b406cda7 100644
--- a/prebuild.xml
+++ b/prebuild.xml
@@ -1759,40 +1759,6 @@
       </Files>
     </Project>
 
-    <Project frameworkVersion="v3_5" name="OpenSim.Region.Physics.BulletSNPlugin" path="OpenSim/Region/Physics/BulletSNPlugin" type="Library">
-      <Configuration name="Debug">
-        <Options>
-          <OutputPath>../../../../bin/Physics/</OutputPath>
-        </Options>
-      </Configuration>
-      <Configuration name="Release">
-        <Options>
-          <OutputPath>../../../../bin/Physics/</OutputPath>
-        </Options>
-      </Configuration>
-
-      <ReferencePath>../../../../bin/</ReferencePath>
-      <Reference name="System"/>
-      <Reference name="System.Core"/>
-      <Reference name="System.Xml"/>
-      <Reference name="OpenMetaverseTypes" path="../../../../bin/"/>
-      <Reference name="Nini.dll"  path="../../../../bin/"/>
-      <Reference name="OpenSim.Framework"/>
-      <Reference name="OpenSim.Region.Framework"/>
-      <Reference name="OpenSim.Region.CoreModules"/>
-      <Reference name="OpenSim.Framework.Console"/>
-      <Reference name="OpenSim.Region.Physics.Manager"/>
-      <Reference name="OpenSim.Region.Physics.ConvexDecompositionDotNet"/>
-      <Reference name="BulletXNA.dll" path="../../../../bin/"/>
-      <Reference name="log4net.dll" path="../../../../bin/"/>
-
-      <Files>
-        <Match pattern="*.cs" recurse="true">
-          <Exclude name="Tests" pattern="Tests"/>
-        </Match>
-      </Files>
-    </Project>
-
     <!-- OpenSim app -->
     <Project frameworkVersion="v3_5" name="OpenSim" path="OpenSim/Region/Application" type="Exe">
       <Configuration name="Debug">