you don't need to triangulate your cylinder, You could consider using GJK for this, and an open source implementation can be found in Solid 2.0: <http://www.win.tue.nl/~gino/solid/index.html> there is a recent thread on how to use Solid in a physics engine on <http://groups.google.com/groups?hl=en&threadm=3C43D602.6090306%40animat s.com>