I needed a very complex, yet organic looking mesh for a short 3D animation. This kind of geometry would be horrifying to sculpt by hand, and the iterative/semi random element let me play around with several forms before settling on one to render.
The tree’s skeleton is created recursively, with magnetic forces at each level pushing apart each limb in order to create an attractive shape. The mesh is then “grown” from node to node to create the final tree.
Paul Miller and I worked on a modified version of this code to create a larger world tree for a short animation. I exported the final mesh to Z Brush for cleaning and texturing, and Paul did some lovely renderes in Maya.