http://renderman.pixar.com/resources/current/rps/appnote.28.html
See article briefly above:
With opensubdiv in the works, I know I’m not alone in wanting to use PRMan’s semi-sharp poly features to limit my required geometry. The problem is though, that I can’t for the life of me figure out how I would take that feature into account when creating displacement maps in Zbrush. I know that Zbrush supposedly supports Maya file format, but I suspect it doesn’t take creasing weights into account when doing subdivision. I also know that we can sort of manually set creasing in Zbrush itself to approximate it, subdividing for the first few iterations with the mesh creased and then releasing the creases to smooth later stages. The question I have is what are the best practices to accomplish displacement projection on these weighted sub-d surfaces? Are we simply too close to the bleeding edge to be pulling this off predictably yet? Has anyone else worked through this problem and developed a workflow that gives them good results? Thanks in advance for your contributions to this thread.