subdiv approximation smooth uv's issue

onthevirg

Hi,

I've been trying to render a zbrush generated displacement maps using mental ray's subdiv approximation and displacement approximation nodes in maya 2008 SP1. I've used scott spencer's method, and have been able to get the displacement looking fine with no seams, HOWEVER it would appear the UV's on the subD surface that mental ray generates, has different uv's than the zbrush generated map( stretching and faceting are present. Since the uv's in zbrush arent smoothed, I'd like to be able to just turn off smooth uv's with the subdiv approximation node.

Is there any way to adjust the subdiv approximation node's ability to smooth or not smooth uv's? The catmul clark (CCmesh) setting will match my uv's but will give me those tell tale seams. Does anyone know a fix or a work around? If you know anything please let me know! I'm dying here at work!

EarthQuake

How about this, load your mesh that has "correct" uvs(that match your image) apply your image, and then load up your other mesh that uses sub-d, and just bake that image down to the proper sub-d uvs. Will that work?

onthevirg

unfortunately no. basically what's happening is that I can't actually look at the Subd uv's because mental ray generates that mesh only at render time. the result it gives after rendering is that of changed uv's i'm 99 percent sure that it is merely smoothing my uv's when it converts to mental ray subd at render time. I wish I could just smooth my uv's on the zbrush model, but unfortunately zbrush's smooth uv method is different from the way that mental ray is doing it. i'm now in the process of looking through the mental ray docs to see if theres any other way to go about this.

this is one of the most frustrating things i've run into in maya so far....so simple yet so impossible?