When I use the überenvironment light, I some times get theese squares in my render :(
Does anybody tkow what it is?, and even better how to fix it???
There is a lenghty thread, and part of it deals with the grid lines showing using UE. The part you need starts here : http://www.daz3d.com/forums/discussion/6814/P45
I am not sure if it was resolved or not, but the information may help you.
Answer on this page http://www.daz3d.com/forums/discussion/6814/P75
The answer is ANY Shadow Bias above .6 will fix it. Open the UE light and find Shadow Bias and test with .6 or higher.