Which Renderers Support Custom Shaders?

For film production and special effects for TV and movies their are basically two widespread renderers but I will add another renderer to the list because this renderer was originally designed to be very close to PRMan¹ and I expect it to be more and more important to the industry in the future:

• RenderMan compatible renderers. RenderMan® is a registered trademark of Pixar. The RenderMan Interface is a standard interface between modelling programs and rendering programs capable of producing photo-realistic quality images. It's defined in a specification published by Pixar under the title The RenderMan Interface. There are a lot of RenderMan compatible renderers but I will focus only on a few of them:
  • PRMan² This is Pixar's implementation of the RenderMan Interface. In the past it was a pure scanline renderer based on the REYES³ architecture. Today it's a hybrid approach which includes ray tracing and global illumination features. Pixar published the basics about shader writing and RenderMan in the book [1] which was for a very long time the only book available on this subject.

  • AIR is another commercial implementation of the RenderMan Interface but because of it's low price it's an alternative to PRMan and it has a few very interesting features⁴.

  • Pixie is a free implementation and one of the RenderMan compatible renderers which come with the full source code. I think this is interestedly enough to mention here for the few people who would like to know more about: How to implement a RenderMan compatible renderer?

  • BMRT⁵ was for a long time the only freely available RenderMan compatible renderer. Albeit it did not come with the source code. The reason why I mention it here is that you still can find versions of BMRT on the Internet and that the book [2] is about PRMan and BMRT. There are many examples in that book which will work for both renderers without changing the shaders.

  • Entropy was a commercial implementation of the RenderMan Interface by a company called Exluna but it disappeared from the market after SIGGRAPH 2002 together with the official web page for BMRT. Both renderers were implemented by Larry Gritz the coauthor of the book [2] and you will still find a lot of useful comments by him on the news group about RenderMan⁶.

  • Angel was written by the author of the third book about RenderMan. See [3] for reference. The renderer is freely available for Linux, freeBSD, SGI, and Windows and there was also a port to the Playstation.

• Mental Ray is a commercial general-purpose renderer from a company called mental images. See [4] and [5] for references. You can't buy the software directly from mental images but it's integrated in a lot of commercial modelling and animation systems and you can get the software from dealers for this packages. With the latest edition of the second book about mental ray you will get a demo version of the renderer which should enable you to use all shader writing techniques described in both books without the need to buy a full license of the renderer.

• Mantra is a renderer which comes with Houdini from Side Effects. Houdini's VEX language is loosely based on the C language but takes pieces from C++ as well as the RenderMan shading language. The reason why I include this renderer is that Side Effects offers a non-commercial version called Houdini Apprentice and you can render with Mantra for free. The commercial version allows you to render with both PRMan ⁷ and mental ray. Houdini's VEX Builder can be used to write shaders for Mantra by simply connecting operators. This is a concept which is found in other packages as well and in theory you can use it to write even shaders for RenderMan and mental ray. Pixar offers a program called SLIM with their RenderMan Artist Tools (RAT) and AIR comes with a similar program called Vshade⁸.