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Disney BRDF material

Posted: Wed May 29, 2019 4:05 pm
by Dade
Stefan Bergmann has implemented Disney BRDF material from Siggraph 2012 paper in LuxCoreRender for his mater thesis and he was so kindly to donate the code back to the project.

The new material is now available on the main branch (for CPU rendering, OpenCL support will follow soon).

Some demo rendering from Stefan:

Clearcoat with rough metallic
Image

Cloth using Sheen
Image

Glossy
Image

Matte
Image

Mirror
Image

Subsurface approximation
Image

Re: Disney BRDF material

Posted: Wed May 29, 2019 4:11 pm
by provisory
Wow, fantastic news! Thank you Stefan!

Re: Disney BRDF material

Posted: Wed May 29, 2019 4:17 pm
by provisory
Are there any limitations (e.g. does it work with BiDir)?

Re: Disney BRDF material

Posted: Wed May 29, 2019 4:17 pm
by lacilaci
Great news!

Re: Disney BRDF material

Posted: Wed May 29, 2019 4:26 pm
by epilectrolytics
Awesome, big thanks!

Re: Disney BRDF material

Posted: Wed May 29, 2019 4:41 pm
by Sharlybg
Don't understand what is going on. What is the bonus for having Disney BRDF material ?
how different it is from the current implementation ?

Is it more realistic ? faster to sample ?

We don't need principled shader now ?

Re: Disney BRDF material

Posted: Wed May 29, 2019 5:06 pm
by epilectrolytics
Disney = principled shader, see here.
It was not yet implemented in Luxcore but planned for v2.3.
It is more realistic but slower to sample because it has always a reflective component.
If fully implemented it should work similar to Cycles principled shader.
From what I see OCL code and Blender integration are still missing.

Re: Disney BRDF material

Posted: Wed May 29, 2019 6:00 pm
by lacilaci
is it brdf or bsdf if it has subsurface? I also wonder what is this approximated subsurfacing.

Do you plan to build future work on it? Adding translucency, thin film layer, will you turn this into a monster ubermaterial for 2.3? I hope it renders fast too...

Re: Disney BRDF material

Posted: Wed May 29, 2019 6:10 pm
by provisory
If it works well, then it must make the switch between Cycles and LuxCore really easy, which would be a big step forward.

Re: Disney BRDF material

Posted: Wed May 29, 2019 6:26 pm
by Dade
lacilaci wrote: Wed May 29, 2019 6:00 pm is it brdf or bsdf if it has subsurface? I also wonder what is this approximated subsurfacing.
It is a BRDF, no ray it is transmitted but it can include SSS look-like appearance.

You can just check the original paper if you want more details: https://disney-animation.s3.amazonaws.c ... tes_v2.pdf (you can skip the math/coding stuff and just look at picture at pag. 13)