This project was something that I tinkered around with from maybe 2008 - 2010 adding little features here and there. I eventually scrapped it because there were underlying problems in the way I built the KD tree to store triangles - I didn't know how to handle triangles that intersected the clipping plane, so I'd duplicate them and put them in both branches. This wasted memory and led to rendering glitches.
I also used a really greedy algorithm for creating the KD tree which meant several minutes to start up for large (100K+ polygon) models.
This was intended to be a realtime raytracer - so it accomplished this by collecting multiple frames together.
These videos are sped up so that each frame traced is one frame of output. These actually took several minutes to output.