General collision detection involves checking the distances between every point and every other < Not really. If you have a smart internal representation of the meshes into smaller and smaller sub-meshes it is possible to very fast calculate which of those that are so close to each other that a collision may occure. Then you perform the actual calculations on those small segments. I've just implemented this in a hobby project of mine and it works fine. The calculation time is reduced very very much. Say if i have a scene with 15.000 polys. Checking every polygon with every other polygon will result in about 15.00015.000 = 225.000.000 checkings. But if you can reduce the problem to say five areas where two poly groups are close to each other and each group contains only about ten polygons. => 1010*5 = 500 checkings! The problems isn't really this easy but the principle works. /Ohman