Was wondering if anyone has any ideas on creating Alpha z-levels.  Meaning the further from the camera you are, the more transparent it becomes.  Current the camera will change the size based on the perspective, but I'd also like to change the alpha.  I'd like to do this at some global level, meaning I don't want to check the z position of every object and modify it's alpha as the camera moves.  I also don't want to modify the perspective so that it just completely clips it.