Reyes rendering is a computer software architecture used in 3D computer graphics to render photo-realistic images. It was developed in the mid-1980s by Loren Carpenter and Robert L. Cook at Lucasfilm's Computer Graphics Research Group, which is now Pixar. It was first used in 1982 to render images for the Genesis effect sequence in the movie Star Trek II: The Wrath of Khan. Pixar's RenderMan was one implementation of the Reyes algorithm, until its removal in 2016. According to the original paper describing the algorithm, the Reyes image rendering system is "An architecture for fast high-quality rendering of complex images." Reyes was proposed as a collection of algorithms and data processing systems. However, the terms "algorithm" and "architecture" have come to be used synonymously in this context and are used interchangeably in this article. Name Reyes is an acronym for Renders Everything You Ever Saw (the name is also a pun on Point Reyes, California, near where Lucasfilm was located) and is suggestive of processes connected with optical imaging systems. According to Robert L. Cook, Reyes is written with only the first letter capitalized, as it is in the 1987 Cook/Carpenter/Catmull SIGGRAPH paper. Architecture The architecture was designed with a number of goals in mind: Model complexity/diversity: In order to generate visually complex and rich images, users of a rendering system need to be free to model large numbers (100,000s) of complex geometric structures possibly generated using procedural models such as fractals and particle systems. Shading complexity: Much of the visual complexity in a scene is generated by the way in which light rays interact with solid object surfaces. Generally, in computer graphics, this is modelled using textures. Textures can be colored arrays of pixels, describe surface displacements or transparency or surface reflectivity. Reyes allows users to incorporate procedural shaders whereby surface structure and optical interaction is achieved using computer programs implementing procedural algorithms rather than simple look-up tables. A good portion of the algorithm is aimed at minimising the time spent by processors fetching textures from data stores. Minimal ray tracing: At the time that Reyes was proposed, computer systems were significantly less capable in terms of processing power and storage. This meant that ray tracing a photo-realistic scene would take tens or hundreds of hours per frame. Algorithms such as Reyes which didn't generally ray trace run much faster with almost photo-realistic results. Speed: Rendering a two-hour movie