OSL

OSL is an acronym that can refer to several different technologies in computing. Two prominent uses are Open Shading Language, a shading language for physically based rendering, and the Open Software License, an OSI‑approved free software license. Other uses exist in specialized domains, but these two are the most widely recognized in technology contexts.

Open Shading Language (OSL) is a domain-specific, open-source shading language designed for programmable shading in renderers. Developed initially by Sony Pictures Imageworks, it provides a C-like syntax and a library of built‑in functions for materials, lights, and volumes. OSL emphasizes portability across different rendering engines and supports features such as light-transport closures to model how light interacts with surfaces. It is used in commercial and open-source renderers and is maintained by a community consortium; its source code and specifications are publicly available.

Open Software License (OSL) is an OSI-approved free software license intended to govern redistribution and modification of software. It is a copyleft-style license that requires modified versions to be released under the same terms and to include the license text, with terms addressing patent licenses and warranty disclaimers. It is an alternative to more widely used licenses such as the GPL and is selected by a subset of open-source projects for its particular legal wording and compatibility considerations.