This tutorial covers how to to combine the light effect created in the previous tutorial vimeo.com/13322805 , using render layers. It also points out some problems that can occur when using the Pass Index method.
The finished .blend can be downloaded here: megaupload.com/?d=GTSJ5JUB
Note: In the "Room with Glass Tubes" (blenderartists.org/forum/showthread.php?t=192147) scene the lights where combined using the Pass Index while the Tubes whee combined using render layers. So you can even mix the "filtes"(Pass index/Render Layers)
On a final note I apologize if my voice is hard to understand, but it seems that i caught a cold so my nose was partially stuffed during the recording.
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