Star Wars Episode 1: The Phantom Menace - Ghost Gun
When Qui Gon and Obi Won are in the room where they are gassed (in the beginning), and the squad of robots are standing there, the nearest robot's hand goes right through the Gun!
I believe half of those droids were computer generated to save on money, and yes, computer generated images go through one another because in the computer there are no boundaries to anything and no solids.