Rigid Body:: Continued

Alright, time to take this one step further people!
The basics are in this thread, but it’s in the news & chat section.

I had something in mind but fail to realise it.
I created a plane with the wave effect on it.
On top of the plane I put a set of spheres.
The idea was to have the balls react to the wave and jump up.

Now they don’t seem to jump up but simpy fall of :]
I have included the .blend to get an idea.
Did anyone accomplish anything of the sort?
Is it possible for the rigid body to interact ONLY in the Z direction so it won’t fall of?

If you create a constraint for the bodies, you can constrain movement along one of the axis’.

I know very little about the game system, and was only able to have it constrain one axis, but not X and Y.

I hope this helps in some small way.