hmmm... when you say primitives, you mean, like primative primatives? :) how about terrains? cuz then i can do puff clouds ;) i was just reading real world bryce (2), and using spheres to build up volumetric clouds is pretty standard (its even in the vue tutorials). thing is, they use like.... 25 spheres. you need lots of overlapping to get the un-sphere-like cloud shapes. can you say six overlaps and my transparency is screwt? ::sigh:: :)