Gravity

[devomage]

If yes, then the scene "Physics: Interaction with a Curvy generated mesh" in the WebGL demo does something similar.

That scene from my vantage point:  moving the ball to that first slope should have caused it to roll...  I then assumed it was just momentum from the keypress.

Yes, either a set of sphere or a single.  I need to simulate the sphere rolling down the U shaped mesh.  A single sphere would certainly pass point C - but eventually would settle at point C.  A set of sphere released at the same time should collide at point C.

The sphere will have a RigidBody with an optional physics material.  Of course, this is how i would like things to work - this might not be reality though.