Well, I started worked on a spare time project, called Structure Synth: a small application for generative structure synthesis (in 3D). The app itself will be built around an embedded editor with a OpenGL visualization window next to it. Here is a mock-up shot:
The structures are designed in a simple language, EisenScript (named after the Great Russian director, Sergei Eistenstein, of course). It will be similar, but not identical, to the Context Free Design Grammer that Context Free uses.
An EisenScript defines a Rule Set, where each rule is defined as a number of Actions.
An Action would typically be to perform a Transformation and either call another rule, or one of the built-in drawing primitives. As in Context Free rules can be defined recursively in terms of themselves.
Rules are allowed to be ambiguous: more than one definition for a rule can exist, and when ambiguous rules are encountered the Builder will choose one at random. Again, as in Context Free, it will also be possible to specify a weighting for each of the rule definitions.
Here is an example of how an EisenScript rule set might look:
Structure Synth will be built in C++/Qt4.3/OpenGL and will be Open Source (GPL). It should be cross-platform (Windows, Linux, and Mac).
I’ve started a subversion repository here (Google Code Hosting), but will probably move to SourceForge.