of course, a thesis is never finished, only submitted. multiple cycles of submit and revise on my masters' thesis took up most of early 1998 (along with a well-earned vacation). so it wasn't until june that I was able to really start working on my phd. while working on my tree models for my masters, I had been keeping track of other research in the lab.
george sealy had been working on converting models built using constructive solid geometry into volume models. one side effect of this is that volume models can be polygonized and rendered very fast using 3d accelerator cards. I thought that it would be useful to investigate interactive design of csg models using a technique similar to this. this could have many important applications in engineering design and solid modelling.
the basic idea was to cast rays against the algebraic primitives that make up the model, and join the intersection points up into polygons. initially, I had vague thoughts of using an octree space-subdivision technique to determine what parts of a model were changing, and only recomputing these sections. unfortunately, the problem with this is that it's just too expensive to re-polygonize part of the model when the user moves it around.