Reyes is the rendering architecture that powered early versions of Pixar’s RenderMan. It was described by Robert Cook, Loren Carpenter, and Edwin Catmull in their 1987 SIGGRAPH paper “The Reyes Image Rendering Architecture” (DOI 10.1145/37401.37414), one of the most influential rendering papers ever published. The name Reyes is a backronym for “Renders Everything You Ever Saw,” and also a nod to Point Reyes, California, near where the work was done.
The authors set out specific design goals: the renderer had to handle scenes of essentially unlimited geometric complexity, produce high-quality images with effects like motion blur and depth of field, and do so within a reasonable, predictable amount of computation. To meet these goals they rejected a pure ray-tracing approach, which was far too expensive on 1980s hardware for scenes of the complexity Pixar wanted to render.
The central idea is the micropolygon. Reyes dices every geometric primitive into a grid of tiny flat quadrilaterals, each roughly the size of a single pixel or smaller. Shading is then performed once per micropolygon vertex, which decouples the cost of shading from the cost of sampling and makes programmable shaders practical. The shaded micropolygons are sampled and composited into the final image, with stochastic sampling used to produce motion blur, depth of field, and antialiasing.
Because primitives are diced into uniformly small pieces and processed in coherent batches, Reyes can stream through enormous scenes without holding the entire model in memory at once, and it gives roughly linear scaling with scene complexity. This combination of programmable shading, high-quality sampling, and bounded memory use is exactly what a feature-film pipeline needs, and it is why the architecture underpinned RenderMan for many years.
Pixar’s own evolution-of-RenderMan page confirms the lineage, noting that RenderMan was “built on a system called Reyes” and that the Reyes algorithm “allowed Pixar to make the first fully computer-animated feature film, Toy Story (1995).” Over time RenderMan moved on to hybrid and full path-tracing architectures as hardware improved, but the Reyes paper’s ideas about micropolygon dicing and decoupled shading remained influential well beyond Pixar, shaping how the industry thought about scalable, high-quality production rendering.