Update: Rafael has provided this reply:
While I initially used Sketchup for very-fast prototyping, I have since that last Sketchup post, ported most of my work to Autodesk's ObjectARX, and am currently working with AutoCAD and Dassault System's CATIA. There's a very high probability of a Sketchup port in the mid-term future as it's a very good platform, I will definitely keep you posted about that.
Rafael, a student of computer science and artificial intelligence at the University of Sussex, posted a series of images from his research project about form-generation and genetic algorithms.
The interesting thing is that he is porting his code to use SketchUp and Ruby. Unfortunately, there is no mention of any code to download, nor is there any mention of the terms of availability.