OK, this is it: The 7th installment of the ray tracing tutorial series. Over the last few weeks I worked very hard to improve the speed of the ray tracer, and I am quite proud of the results: Render times for the scene in article 4 (you know, the sphere grids) dropped from 7 seconds to less than 2 seconds. To put this power to good use, I added a triangle primitive, and a 3ds file loader. The d