Physically-Based Shading at Disney (2012) [pdf] | Hacker News Reader

Physically-Based Shading at Disney (2012) [pdf]

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35 pointsTomte11 comments

Teacher of 3D modeling and VFX here. The principled shader workflow has made our lives a lot easier. We can now fairly guarantee consistency of appearance from one app to another.

Still unsure of the technical details in the paper, but the results look great. Of all the parameters it offers, base color, metallic and roughness are suitable for 95% of cases. Also, metallic is almost always binary… zero or 1.

Hey prof - can you point me to any solid resources on building PBR materials from real-world reference? I’m just kind of going by eye and intuition right now but I know it’s more of a science than that.

Does this help? https://physicallybased.info/

It was actually this site that made me realize my understanding of this material is weak!

Jessermeyers link (below) is a good one.

My own teaching is a bit more application specific. Here is the material I wrote for Blenders BSDF shader…

https://rmit.instructure.com/courses/87565/pages/blender-the...

Also, I don’t Normally recommend YouTube vids, but this one gives a really good lowdown on the subject…

https://youtu.be/4H5W6C_Mbck

I also learned a lot from looking at photo scanned texture maps. You get a good feel for the channels that way. Here is a list of relevant recourses.

https://rmit.instructure.com/courses/87565/pages/where-to-fi...

Killer thank you!

Blender’s Principled BSDF is based on Disney’s work. Maybe you’re looking for something more advanced, but Andrew Price (Blender Guru, the donut guy) has some decent videos talking about how to create realistic materials with it. I don’t have any links at the moment, but they should be easy to find on YouTube.

EDIT: Daub posted the one I was thinking of.

I’d be curious to hear what issues you were having before this principled workflow and how it improves consistency. Is it because apps have all adopted the Disney shader specifically? Partly wondering because the specific shader parameters you mentioned, base color, metallic, and roughness were standard in CG/VFX production 15 years or more before this paper was written. (I wrote shaders at PDI back then.) They didn’t mean exactly the same thing from app to app, but I think today if we’re not talking about the Disney BRDF, they still don’t mean the same thing from app to app since they’re not physical parameters.

Glad to speak with someone of your experience!

Certainly when I first started teaching 3D, we had to choose between Blinn, Phuongs, Lamberts and suchlike. Different objects would be assigned different shaders. That alone made workflows tricky. This was around ten years ago.

Getting apps to talk to each other was hit and miss. In VFX, two shader results in two different apps that are slightly different in impact may as well be very different.

Though Blender has lots of legacy shaders, I forbid students from using anything but the principled BSDF. This lock-in to one shader makes life a lot easier. Also, the Substance painter to blender to unity consistency is now pretty slick.

I cringe when people use the term Physical Base Material, because you really want a shader model to be unrealistic and but highly controllable. The consistency of appearance part makes sense, I wish this was branded differently.

I've been following this paper to implement materials in a raytracer I'm building. As well as https://blog.selfshadow.com/publications/s2015-shading-cours... and this homework assignment https://cseweb.ucsd.edu/~tzli/cse272/homework1.pdf

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