I recently noticed a rather cool feature in Christie's (otherwise terrible) warp software "Twist". It actually compensates the brightness of the surface depending on how far away it is from the projector. In other words, it smoothly gets dimmer for surfaces that are physically closer to the proj resulting in a visually even surface. I've had this be a time consuming problem on a project with madmapper that resulted in me having to manually adjust all the surface's opacities to get an even looking glow on solid colours. It's a pretty cool feature in twist, which is a bit strange because it doesn't even do perspective correct warping of the image...but knows enough to compensate the brightness. Anyway, thought it was worth a mention.