The Design and Evolution of Disney’s Hyperion Renderer

Abstract

Walt Disney Animation Studios has transitioned to path-traced global illumination as part of a progression of brute-force physically based rendering in the name of artist efficiency. To achieve this without compromising our geometric or shading complexity, we built our Hyperion renderer based on a novel architecture that extracts traversal and shading coherence from large, sorted ray batches. In this article, we describe our architecture and discuss our design decisions. We also explain how we are able to provide artistic control in a physically based renderer, and we demonstrate through case studies how we have benefited from having a proprietary renderer that can evolve with production needs.

A Path‐Tracing Monte Carlo Library for 3‐D Radiative Transfer in Highly Resolved Cloudy Atmospheres

“…However, this will only be efficient if the algorithms that request the data are designed according to their out‐of‐core nature. For instance, the strategy implemented in Hyperion, Disney's out‐of‐core renderer (Burley et al, ), consists of tracking paths in bundles instead of individual rays, thus making intensive use of the loaded data before unloading it when memory space runs out.…”

Improving Temporal Antialiasing with Adaptive Ray Tracing

“…Even though matching sample patterns between ray tracing and rasterization appears to be the best approach at first, different sample patterns may enable adaptive ray tracing with 8× sampling to converge to 32× quality over just 4 frames. We look to production renderers [3,5,8,9,16] for inspiration in determining highercount sample patterns. Correlated multi-jittered sampling [14] is commonly used today.…”

Art-Directed Composition in Dynamic Real Scenes

“…Our final goal is to support art direction for non-photorealistic appearance editing. While achieving Goal 2 helps artists to edit realistic appearance, art direction may call for unrealistic lighting edits for illustrative styles, characters originally drawn in non-photorealistic media, and even clean up realistic shadows [31]. Like in Goal 2, this goal aims to automatically preserve stylised art direction under changing lighting, which is unsupported by existing techniques.…”

“…A director will often ask to place lighting and shadows that are fictitious yet artistically convey the intended look. Although this is more important for stylised rendering, shadows are also edited non-physically, in realistic rendering [31]. This chapter addressed automating art direction under varied real-world lighting conditions, but ignores shadow variation as the light direction varies.…”

“…This is because the abstract two-tone shading style creates undesirable shadow shapes, or removes important surface details, when illumination changes. Even in realistic rendering styles, artists require fine-grained, non-physical, shadow shape control [31]. Stylised feature films thus require frame-by-frame editing during post-production which is inefficient, especially when repeating the same manual edits in different shots.…”