Volume Rendering for Pixar’s Elemental

This work presents recent updates to volume rendering in RenderMan, the production renderer used at Pixar. With the advent of increasingly complicated volumetric assets such as those seen in Pixar’s films Soul and Elemental, our aggregate volume renderer required changes to handle complex water based characters; optimizations for complicated scenes; better handling of transform blur; and improved support for volumetric matte holdouts. These changes allowed us to render an immense number of complicated and detailed volumetric characters in Elemental.