User:LeonardoSegovia/GSoC 2018/Reports/Community Bonding

Implementing a Hair Shader for Cycles

Report: Community Bonding period

BlenderArtists community survey

bzztploink on IRC suggested:

2018-04-24 16:12:01 bzztploink you could also think about having a thread on blenderartists.org so people can follow your progress and give feedback

Thread is here.

Summary:

• A substantial number of users asked if the end result would be a principled shader (à la Disney über-shader).
  • Brecht says this will be indeed the case:

2018-05-07 17:44:29 brecht I didn't mentioned it explicitly, but the idea was for the new hair shader to be called "principled hair"

2018-05-07 17:44:41 brecht so that we have principled bsdf/hair/volume

2018-05-07 17:44:52 brecht and user will then immediately understand it's an "ubershader" type thing

• There were a number of complaints about:
  • The lack of documentation on the current shader. There is no explanation on how to setup a proper hair material, only the physical meaning of the parameters and that’s it.
  • The usability of the current shader. Some artists try to make the most of it by using complex nodegroups, but that’s a stopgap measure at best.
• The primary concern was about the shader’s interface:
  • Would the modes (R, TT, TRT) stay separated?
  • Intuitive parameters

Development environment preparation

I’ve setup MS Visual Studio 2017 on Windows 7 x64. I had CUDA installed from an earlier postgrad course, so no news on that front.

I tried to follow the BlenderWiki page on the subject. The make script finds only the 32-bit toolchain, even if called from within the 64-bit Build Tools CLI. I ended up following Manual CMake Setup to force a fully x64 build toolchain, using the CMake GUI to finish off the process.