private static Quaternion ToXNA(Vrpn.Quaternion q)
 {
     return new Quaternion((float) q.X, (float) q.Y, (float) q.Z, (float) q.W);
 }
 private static Vector3 ToXNA(Vrpn.Vector3 v)
 {
     return new Vector3((float) v.X, (float) v.Y, (float) v.Z);
 }