Hi,
I am working on small tutorial that help you understand basic principles of raytracing and have some fun with Houdini.
You will be able to create fully working raytracer inside VOPS without any coding or scriping (no tricks or cheats).
It is step by step, written tutorial explaining very basic principles of this topic so no need to worry about math or lack of high houdini skills.
Raytracer will have abilities to calculate simple shaders, anti aliasing, depth of field (and more to come)
I am trying to add part by part every week on my website http://tmdag.com, Have fun!