oh..well, my work here is done..;) Not sure what collision detection in rendering is (in networks, it's CSMA/CD and such..;). I'd just take a torus, grab half, pull hard on the major axis. Duplicate along the axis, rotate the dupe on that axis 90 degrees, and wash, rinse, repeat to taste..but that's me..;)

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)