public RigidBodyEntity(Vector3 pos)
        {
            body = new RigidBody(pos);

              debug_compass = new DebugCompass(this.CenterOfMass);

              debug_compass.LoadContent(null);
        }
        public ModelEntity(Model model, IRigidBody body, EntityGeometryData geoData)
        {
            this.body = body;
            this.Model = model;

            this.GeometryData = geoData;
            DebugCompass = new DebugCompass(this.CenterOfMass);
            DebugCompass.LoadContent(null);
        }