These tools are a framework to incorporate various interaction and rendering techniques that I have developed over the last few years.
The system currently includes an image compositor, a geometry re-renderer (originally presented at SRT2003: Baking Micropolygons), and a ray server client (SRT2005: The Interaction Trick). The system can interpret RSL shaders and uses RIB for its scene descriptions. The majority of the system was described in Course 25 at Siggraph 2006.
The original notes for the Interaction Trick are available here.