A hybrid approach to procedural tree skeletonization
James Bartolozzi, Matt Kuruc · 2017
The curve hierarchy skeleton has been a foundational component of Pixar's vegetation pipeline since Cars 2 (2011). This skeleton is leveraged when building flow fields for texture synthesis, generating procedural secondary vegetation detail, and as a basis for simulation rigs. Our current skeletonization pipeline is built around mesh contraction [Shek et al. 2010] [Au et al. 2008] which is sensitive to the underlying topology. This method creates undesirable curve structures when modelers add musculature to the trunk mesh. Technical directors would reapply manual fixes to the skeleton over the course of iterating on the model. Recent work examining constructing skeletons using point clouds and volumetrics inspired us to develop a new hybrid approach. This alternative to the traditional mesh contraction algorithm has shown to be fast, reliable, accurate, and minimizes constraints on our modeling artists.