Thanks folks, I enjoyed finding out about all these applications. I expect there are more - quite a lot of inventive and talented people around. Here is another of mine- this time started from one of my  abstract watercolors.I usedit as the image for IBL on Jessi's head (after face room modifications). I positioned two mirrored walls and a "floor" mirror to generate the poser image. This was in turn used as basis for the watercolor "Lost in Reflection",to complete the mutual feedback cycle. (good example of things you can do to virtual model and not to real ones- even if I had the right mirrors,dont think a realJessi would like her head sliced off to be placed on a mirror...)

"I paint that which comes from the imagination or from dreams, or from an unconscious drive. I photograph the things that I do not wish to paint, the things which already have an existence."
Man Ray, modernist painter
http://artpearl.redbubble.com/