Hi, I'm working on a game where I want to only render geometry that sits inside the confines of 6 sided box, somewhat like a fishtank. Any geometry outside the tank should be invisible. I will be using Unity Pro with Windows. The effect I want is like the example on the right in this image :- http://imgur.com/bWaDXJp The objects that might intersect the tank it are animated, so I need to do this at runtime. Maybe I could do this by checking all geometry for an intersection every frame. But presumably it could be very slow. Is it possible to do something like this using a shader? I'm not asking for a full solution, just suggestions that I could research. Thanks for any suggestions.