RenderMan

RenderMan is the name of a computer graphics rendering technology invented by Pixar Animation Studios; an implementation of Pixar's photorealistic 3D description standard, the RenderMan Interface Specification.

RenderMan is often used in creating digital visual effects for the Hollywood blockbuster movies of today such as Star Wars and Lord of the Rings.

The name RenderMan can cause confusion because it is often used to refer to two different things:

The RenderMan Interface Specification (RISpec): Pixar's technical specification for a standard communications protocol (or interface) between modeling programs and rendering programs capable of producing photorealistic-quality images. This 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 future-proof enough to encompass advances in technology for a significant number of years.
PhotoRealistic RenderMan (PRMan): A RenderMan-compliant rendering software system developed by Pixar themselves based on their own interface specification. This is used internally at Pixar and also licensed to third parties.

What set the RenderMan Interface Specification apart from other standards of the time was the specification of a Shading Language (SL), which allowed material descriptions of surfaces to be described not only by adjusting a small set of parameters, but in an arbitrarily complex fashion by using a C like programming language to write shading procedures.

Further reading