Gaieus was right, I have came across same problem before. I was create a surface and painted it with translucent material and realize that I need to divided them up and create a frame around it. Once I did all that I notice that when I orbit around those surface on the frame I create by drawing a line to divided the original face wasn't look solid. It took me a while to figure it out.
Great work guys lot helpful information here.
neng83