Cycles: Fix missing specular tint for SVM transmissive Principled BSDF #112894

This is probably a discussion that should be had between you, @weizhen and others. But I just wanted to explain my pull request just in case it wasn't clear.

#112192 changed the specular tint from a float to a colour.
Either during the merge of that change into #112848, or one of the revisions of 112848, the specular tint was removed from the reflective part of the transmissive component of the Principled BSDF in the SVM implementation of the material. OSL and EEVEE were left untouched. I assumed this was a mistake and added the Specular tint back to the SVM implementation with this pull request.

Just in case it changes anything, a version of Blender 4.0 from two weeks ago, and Blender 3.5.0 both use the specular tint to tint the reflective part of the transmissive component of the Principled BSDF.

It doesn't seem to in Standard Surface or OpenPBR either.

I can't find the specification for OpenPBR, so I can't compare against it. Sorry.

> I thought the specular tint should not affect the transmission component? This is probably a discussion that should be had between you, @weizhen and others. But I just wanted to explain my pull request just in case it wasn't clear. #112192 changed the specular tint from a float to a colour. Either during the merge of that change into #112848, or one of the revisions of 112848, the specular tint was removed from the reflective part of the transmissive component of the Principled BSDF in the SVM implementation of the material. OSL and EEVEE were left untouched. I assumed this was a mistake and added the Specular tint back to the SVM implementation with this pull request. Just in case it changes anything, a version of Blender 4.0 from two weeks ago, and Blender 3.5.0 both use the specular tint to tint the reflective part of the transmissive component of the Principled BSDF. > It doesn't seem to in Standard Surface or OpenPBR either. I can't find the specification for OpenPBR, so I can't compare against it. Sorry.

xZaki commented

2023-09-27 13:58:31 +02:00

First-time contributor

I don't think letting you tint transmission with specular tint would take anything away, in fact the lack of it feels more like a bug to me.
If something like openpbr decides to not have it, we could just make a checkbox that enables this.

I don't think letting you tint transmission with specular tint would take anything away, in fact the lack of it feels more like a bug to me. If something like openpbr decides to not have it, we could just make a checkbox that enables this.

Brecht Van Lommel commented

2023-09-27 14:51:36 +02:00

Ok, let's keep this behavior.

The OpenPBR spec is not public (and not finished) yet.

Ok, let's keep this behavior. The OpenPBR spec is not public (and not finished) yet.

Brecht Van Lommel changed title from ~~Cycles: Fix missing specular tint for SVM transmissive Principled BSDF~~ to Cycles: Fix missing specular tint for SVM transmissive Principled BSDF

2023-09-27 15:57:13 +02:00

brecht changed target branch from main to blender-v4.0-release

2023-09-27 15:57:15 +02:00

Brecht Van Lommel commented

2023-09-27 16:18:56 +02:00

@blender-bot build linux

Brecht Van Lommel merged commit f9dce92767 into blender-v4.0-release

2023-09-27 17:44:59 +02:00

Brecht Van Lommel referenced this issue from a commit

2023-09-27 17:45:00 +02:00

Fix Cycles missing specular tint for transmissive Principled BSDF

Brecht Van Lommel deleted branch fix-transmissive-tint