Reference Material for Shaders

[Midnight Arrow]

https://www.nvidia.com/en-us/on-demand/session/gtcspring21-s31893/

Daz employee breaks down how the shaders work in Powerpoint form, using MDL code, for Nvidia’s GTC conference.

[Alessandro Padovani]

Thank you for this.

Most of the description is already implemented. It is interesting the part on fresnel since unfortunately the model in #1069 doesn’t work and that’s why I didn’t close it yet. Not sure what we miss I’ll have to work on it when I get some time.

[Midnight Arrow]

TBH I don’t even care about Iray fidelity anymore.

The Uber shader file mentions the specularity model is based on Disney’s Burley shader, same as the Principled BSDF. The Disney shader is “artistic” not physically correct, and it’s about to be dumped in favor of Principled V2 anyway. Long ago I said the diffuse textures should just be modulated with an HSV node. After spending all this time understanding the Uber shader’s design (and 3.3 ruining the volumetric skin effect) I’ve come back around to my original conclusion: just use an HSV node to darken the diffuse texture. It’s less complicated and it works great.

[Alessandro Padovani]

I certainly agree that blender can make both easier and better materials than the iray conversion. Indeed replacing and fine tuning materials by hand is an option but it requires extra work, that’s also why the principled option is provided for users who prefer to customize simple materials.

[Alessandro Padovani]

Duplicate of #1069. Closed and added for reference.