Hi there;
In the distant past I remember setting up a material that would let an object with the material applied 'punch' an alpha hole through the scene - the material would occlude other objects behind it and render the object as an empty hole. But for the life of me I can't remember how to do it. Are there any limitations (eg GI) on this method?
Any help would be greatly appreciated.
Thanks!
EDIT: Ha I found it - set diffuse mask to 1.0. Easy!