The links meet each other and slide a bit, rotate around their multiple axes based off of their mass, friction, and of course gravity... I had to turn bounce up to .1 so that they would all fall differently, which is the point of this whole thread... No two chain links ever fall identically against each other, in real life. Well, not round links, anyway. Cubical or flat lnks might fall identically... Here's three quick Maya renders. Kinda OT, but these will all end up in Bryce for rendering... First one is software rendered, middle is Mental Ray (draft), and the last is MR with Global Illumination (photon rendering + raytracing).