Is it possible to constrain an object to a track (for example a circle, spiral, clothoid or other curve) and have its speed calculated by a physics simulation as a result of the forces acting on the object (gravity, drag)? I know that it is possible to constrain the motion to a line using the PhysicsConstraintActor by locking 2 of the 3 axes. But is it possible to make the object follow an arbitrary curve with a given equation?