I would say offhand it's probably a simple matter that the primitives are UV mapped differently that, say, the rocks. It seems that the primitives are far better suited to deal with some materials than anything else is, and anything "fuzzy" shows that pretty well. AS for the random rock generator, I have to wonder: Does it work the same as Solid Growth, or are there certain, defined meshes and it just randomly cycles between them all? If they are based on algorithims similar to Solid Growth, that might explain an incompatiple UVW mapping, which the primitives wouldn't have, since they are always the same. But then again, the Solid Growth trees and plants always display their materials properly, though they often differ dramatically in structure... hmmmmmmm....................