Managing geometric complexity with enhanced procedural models

We illustrate two enhancements to procedural geometric models which allow autonomous procedures to jointly satisfy mutual constraints. One of the techniques adds communications paths between procedures which may affect one another. Conflicts are resolved by modifying communicating procedures as they execute.The second technique is a generalization of widely used subdivision procedures. The termination test of typical subdivision methods is replaced with a "transition" test. The subdivision procedure is augmented with a "script" in the form of a state transition table which controls the procedures' response to external events as well as to the normal termination conditions.In the examples we show how effective these techniques are building complex geometric models with very sparse input.