Cache Points for Production-Scale Occlusion-Aware Many-Lights Sampling and Volumetric Scattering

A hallmark capability that defines a renderer as a production renderer is the ability to scale to handle scenes with vast complexity, including complex illumination cast by a vast number of light sources. In this paper, we present Cache Points, the system used by Disney’s Hyperion Renderer to efficiently importance sample direct illumination in scenes containing up to millions of light sources. Our cache points system includes a number of novel features, such as its ability to do on-line learning of occlusion and factor an occlusion estimate into its importance sampling distribution, and its ability to also accelerate sampling in difficult volumetric scattering cases. Our cache points system has seen extensive production usage on every feature film and animated short produced by Walt Disney Animation Studios over the past decade with enormous success; in this paper, we will survey how the cache points system is built, how it works, the impact it has had on production lighting and artist workflows, and how the cache points system factors into the future of production rendering at Disney Animation.