When the RenderMan standard was first proposed, computer graphics was still an esoteric topic of research practised by skilled proponents. The typical expectation was that these users would be writing their own programs to generate geometry, probably in the C programming language. As a result, the first release of the RenderMan API defined a set of C functions which could be called by modeling programs to pass instructions to a renderer. While the C API is an appropriate mechanism for researchers to use when communicating to a renderer, it rapidly became clear that for commercial production, a more flexible mechanism was required. Users need to be able to generate a scene on one machine, and then pass it to the renderer of their choice running on a renderfarm. For this reason the RenderMan Interface Byte stream (RIB) file format was introduced.