[ODE] conveyor belts and moving platforms

[David McClurg]

In my game, I'd like to simulate conveyor belts.  Looking at the doc, a contact joint using dContactMotion1/2 seems to be the technqiue required.  Does anyone have an example of that?  I looked in ode/test but couldn't find anything.

Also, if i want to simulate moving platforms (boxes with bodies) that the player can jump on, should friction keep the player on the platform or will I need a special contact joint?

If my player is a ccylinder or sphere, and I don't want my player to rotate as it moves in the world via SetVel, how do I constrain the body to not rotate?

Much thanks for any help with these questions