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Glossy Direct/Indirect pass multiplied by the Glossy Color pass using Principled BSDF (Cycles and EEVEE)
Needs Information from Developers, NormalPublic

Description

System Information
Operating system: W10
Graphics card: Titan Xp

Blender Version
Broken: since the principled BSDF was introduced in blender (2.79)
Worked: -

Short description of error
Glossy Direct and Indirect pass are already multiplied by Glossy Color. Glossy color pass is always = 1 (white)

Exact steps for others to reproduce the error

  • Download this file :

  • Render image
  • Compare Glossy pass in the compositor (Left : old glossy shader, right : principled)

as you can see, in the glossy direct and indirect pass, the glossy color is already multiplied :

and glossy color pass is white :

When everything is combined in compositing, the result is correct (because the Glossy color is already multiplied and his pass is white)
but we can't actually work with it with any software.

Event Timeline

Romain Toumi (ToumiX) renamed this task from Glossy Direct/Indirect pass multiplied by the Glossy Color pass using Principled BSDF (Cycles) to Glossy Direct/Indirect pass multiplied by the Glossy Color pass using Principled BSDF (Cycles and EEVEE).Mon, Mar 29, 11:46 PM
Romain Toumi (ToumiX) created this task.

it's a pain in the ass for compositing even if it's a bug by design. Vray/corona any renderer don't work like that with "uberShader".
it's also a pain for denoising passes separatly, it make me to not use the Principled.
I can't see/find why it's like that exept the spec+diffuse albedo>1 ... but that should not be a problem

But isnt this normal for metallics?

Metallic
  Blends between a non-metallic and metallic material model. A value of 1.0 gives a fully specular reflection tinted with the base color, without diffuse reflection or transmission.

https://docs.blender.org/manual/en/dev/render/shader_nodes/shader/principled.html#inputs

It is not like that if metallic is 0.0

Yes, the behavior of the principled shader is normal. The problem is not there.
It's about render passes: The glossy color does not have the correct information. The color is already multiplied to the direct and indirect glossy, and THIS is not normal .

Philipp Oeser (lichtwerk) changed the task status from Needs Triage to Needs Information from Developers.Wed, Apr 7, 11:23 AM

At his point, I would like a decision by the rendering module.