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?

>Complains about homework threads
>Suggests ray tracing

We have ray tracing for like the first three semesters of classes in our computer science department as required in the courses.  Then if you want you can go do more advanced stuff with senior and graduate level classes.

Coincidentally we have a lot of shitty students after their first couple semesters who have no idea what they're doing.