Disney Ubershader vs Principled BSDF on master build

(Matt) #1

I learned Blender a few years ago but was away from 3D modeling for a while, so I am a little out of the loop. Decided to give 2.8 a spin with the new UI and other large updates. Very impressed so far, I honestly can’t go back now and I’m stuck in 2.8+ for good! Glad to be back in 3D, hopefully I go further this time.

I’ve been very impressed with the new Principled BSDF shader, it makes building materials very fast and easy. I’ve read that this is based on Disney’s principled model, so it must be good right? I noticed Ubershader today, is Principled BSDF and Ubershader based off the same model so share the same capabilities or is there any reason to use one over the other? To me it looks like Ubershader was just the first to implement Disney’s model into blender’s material system, while the Principled BSDF node is the blender devs implementation, but both are based on the same model.

Ubershader: http://www.onelvxe.com/ubershaderbeta/

(TheTuxedo) #2

There was a phase a couple years back when PBR and ubershaders were the new thing on the block. Every Blender group and personality was releasing their own version of the ubershader and they all looked and performed slightly differently. Every Blenderer had their favourite; the forum threads were massive and the flame wars were bloody.

Then the Blender devs decided to make the Principled BDSF and end all the bickering once and for all. It’s standardized and used in almost every tutorial since release. It’s built into the code instead of being a massive node tree so it performs slightly better, too.

There are very very very very few occasions where you’ll need a custom ubershader.

(Matt) #3

Thanks for the rundown! Massive and bloody forums threads, glad I missed all that noise. :slight_smile:

Good on the devs to take in into their own hands as well and make everyone’s lives easier.

(CarlG) #4

Also I believe (correct me if I’m wrong here) that the disney is built using disney’s math, something you can’t setup with nodes (enclusures are not available). Such as disneydiffuse and oren nayar diffuse having different responses. Or how you can’t make the sheen response with builtin shaders.

Principled had (still have? don’t know) a problem with clearcoat roughness (original disney uses smoothness, the opposite) as a textured parameter in that it would remain 0 until a certain threshold was reached - looked horrible. Has this been fixed (for Cycles)?

Also Principled is lacking bechman distrubution (only GGX and MS-GGX), which btw isn’t something you’d typically expose in an ubershader (because dropdown selectors can’t be exposed).

Principled will work for 90% if you’re a regular user. Only reasoning to download ubershaders at this points is to see how they’re setup, getting the mindset for them. There are a few times when principled doesn’t cut it and you have to make something of your own (i.e. I think the GGX models are flawed for long tail aniso metals with low roughness values, I use bechman in my own setup for these).