Geometric Diversity for Crowds on the GPU

Pure geometric techniques have emerged as viable real-time alternatives to those traditionally used for rendering crowds. However, although capable of drawing many thousands of individually animated characters, the potential for injecting intra-crowd diversity within this framework remains to be fully explored. For urban crowds, a prominent source of diversity is that of clothing and this work presents a technique to render a crowd of clothed, virtual humans whilst minimising redundant vertex processing, overdraw and memory consumption. By adopting a piecewise representation, given an assigned outfit and pre-computed visibility metadata, characters can be constructed dynamically from a set of sub-meshes and rendered using skinned instancing. Using this technique, a geometric crowd of 1,000 independently clothed, animated and textured characters can be rendered at 40 fps.