Hi Rich, when I did something similar I had the same problem. The way I solved it was to use a very large cube as the wall -- off-camera -- and then use boolean-subtracted cubes to form the windowpanes. Then a point light for the light source. The wall just needs to be large. The windowpane cubes can be grouped together to make them easy to move around the wall to the place you want them. The light will shine through in the proper shape then. Hope this makes sense okay. :)