I'm interested in modeling these aspects of a spinning ball: - collision with an arbitrary hard surface - collision with an elastic surface (e.g. a paddle) - ability to vary the friction between ball and different surfaces - ability to model the curve effects of the spin I looked at the Open Dynamic Engine, but did not find anything about modeling things like air turbulence created by spin. Is there an engine that could do that for me, or do I need to google for "spinning ball physic models"? Kirby

Yep that's what I'm going to do. Just use basic formulas on air resistance, angular momentum, friction, and, I just found out about this, the Magnus Force, which says the curve force is proportional to rate of spin * velocity.