Sun 18th Aug 2013 | News
Blender Cycles code change allows seamless link to inhouse and commercial software.
The Blender Cycles source code has been changed to work with the Apache License v2.0. This is a permissive license that allows Cycles to be linked and used with any program, including commercial software and in-house software at studios.
The design and purpose of Cycles always has been to work as an independent and reusable rendering engine. When Cycles was added to Blender two years ago, the Blender creators decided to release it under GNU GPL first, specifically to ensure it would develop into a well integrated production rendering system for Blender. With that target to be established well, The Blender.org crew feel it’s time to find out how Cycles could work outside of Blender too.
With the release of various libraries by movie studios like OpenEXR, Open Shading Language, OpenSubdiv, PTex and OpenVDB, which the Blender coders hope to use, they also want to contribute something back under a similar permissive license. As Cycles is reasonably stand alone and integrates many of these libraries already, it’s a good candidate to share similarly with everyone.
Note that Blender Foundation and Blender Institute remain committed to further developing Cycles as a render engine for Blender. Developers should integrate it in other applications, and they should especially get involved with the Cycles development team at blender.org.
Blender will of course continue to be available and developed as a GNU GPL project. For an end-user tool like Blender that gives the best protection to ensure the program remains available in a 100% free and open domain. For stand-alone libraries however, the BSD or Apache has proven to work excellently, also for Blender.
Evaluating which permissive license to use has been reviewed carefully. There’s a number of choices we could have selected as well, such as BSD or MIT. However, we already have core Cycles code under the Apache license, mostly related to BVH building and traversal, and SIMD optimizations. We also plan to integrate OpenSubdiv, wich is Apache License 2.0. Even though some of the Cycles code is under the BSD license, combined together it would be determined by the Apache license anyway, so it seems like the logical choice.