Thanks for the explanation, ron. I was actually familiar with most of the concepts, but not in their application to poser. And there were a couple of intersting rules there I hadn't heard before. So, could this be avoided depending on what app you're modelling in? Or are overlapping surfaces always going to give this effect? I use 3d max and haven't ever come across this problem. You didn't find anything weird with room creator in poser 5, did you? Certainly, no other beta-tester with P5 had any trouble. I'm interested in anything like this which may affect my own stuff. I don't like nasty surprises. mac