Aye, Pakled, but a torus is a circle. A chain link is not necessarily circular! Indeed, you'd be hard-pressed to find any chain, anywhere, that is circular. Collision detection is when the polygons do not overlap, just like in real life. Bryce has nothing even remotely like collision detection, alas. If you move an object up against another object, they don't "bump" into each other. They just overlap. In real life, if you move two solid objects together, they cannot occupy the same space at the same time. They actually stop. This happens every time you touch anything, for example. Electroglyph, that's totally the way to go. Thank you very much! Should be a piece of cake, now...