strange render output

[112_cg]

some times when I render a test image it is f***up.. as you can see, what can I do about this?? Whay all the strange collors?????

plees help thanks

[dalomar_cg]

Re: strange render output

Thats all due to overlapping, or coplanar faces. Basically when two mesh faces are in the same place, Vray (or almost any renderer for that matter) has a hard time figuring out which one to render. Subsequently pretty much anything can happen at that point, so a ray can just "die" and yeild a black result, one material as opposed to the other will show up, or certain components of the color (r,g, or b) can get trapped or messed up. There is a function in Global Switches called Secondary Ray Bias that will help this on small things, but not really on things like this (too much overlapping). The only way to really work with it is to make sure your model doesn't have them.