hair going trough body.

Hey guys… i a doing a animation on wich the a ball is going up some stairs and i have hair on the ball. the problem is as the ball is going up the hair goes trough the ball i put a video here to help show what i mean.

http://vimeo.com/2120727

Have you check “collision” on your ball too?
Hair reacts fine with stairs. This indicates that collision is working with the stair’s mesh, at least.