RenderMan by Pixar

RenderMan Interface Specification, or RISpec in short, is an API developed by Pixar Animation Studios to describe three dimensional scenes and turn them into digital photorealistic images. It includes the RenderMan Shading Language.

As Pixar's technical specification for a standard communications protocol (or interface) between modeling programs and rendering programs capable of producing photorealistic-quality images, RISpec is a similar concept to PostScript but for describing 3D scenes rather than 2D page layouts. Thus, modelling programs which understand the RenderMan Interface protocol can send data to rendering software which implements the RenderMan Interface, without caring what rendering algorithms are utilized by the latter. The interface was first published in 1988 and was designed to be sufficiently future proof to encompass advances in technology for a significant number of years.

Built from the ground up as an entirely new product, RenderMan for Maya brings RenderMan's speed, power, and stability directly to Maya users, without the added cost and complexities of our premium, high-end products, RenderMan Pro Server and the RenderMan Artist Tools. If you've been looking for an affordable, easy way to get RenderMan, your wait is over.

MTOR provides a seamless interface between Maya and Pixar’s RenderMan. MTOR automatically translates a wealth of data from Maya, including Maya’s subdivision surfaces. MTOR, however, is much more than a simple file format converter, offering many advanced features for the management of complex scenes to allow a high degree of scalability. Automatic RIB archiving, conditional shader attachment and enhanced scriptability are among these cutting-edge features. MTOR is the backbone of the RenderMan Artist Tools, providing a clean interface with uncompromised extensibility.

Slim is a powerful shader management tool developed to meet the demands of sophisticated productions. Through scripting, Slim’s support for Maya attributes, and its general extensibility, Slim is a capable tool that provides automated and customized solutions for shading workflow. Slim also functions as a shader generator, allowing RenderMan shaders to be generated interactively, without programming. With Slim it is possible to generate a wide range of the highest quality procedural shaders. Slim, as a combined shader generation and management system, plays a key role in the RenderMan Artist Tools.
A Hilarious RenderMan Animation - Alien Sings 'I Will Survive'