Wow!  This is amazing stuff. Students at University of Illinois at Urbana Champaign have come up with a tool and algorithms to insert a 3D Models into photographs and make it look so realistic. The algorithm calculates the lighting and perspective.  There’s minimal work for the novice user to set up the scene’s perspective and light source. The movie shows animated scenes. For instance the billiard balls move and the lighting, shading and shadows change accordingly. The movie is on the technical side since its being presented at SIGGRAPH Asia. Its worth a look any way to behold what they’ve done.

Sources: Hardware, Kevin Karsch