Ray Tracing

Goddamn all of these homework threads. Let's talk about something interesting.

I'm starting work on a ray-tracer for shits, /proggles/ Any tips on speed improvements? It's being written in C.
I know the show stopper (usually) is having to check each element in the scene and see if it has been intersected by a casted ray. Any ideas on improvements in that area?

>>23
Efficiency is meaningless out of context. Efficiency is always subjective relative to the problem at hand and the solutions to the problem. Until you can give me real data, my opinion is that ray tracing is no less efficient at interactive 3D graphics than traditional techniques.