Baking roughness affected by base color (Principled BSDF) #117081

New Issue

Georg K · 2024-01-13T04:44:31+01:00

Georg K commented

2024-01-13 04:44:31 +01:00

System Information
Operating system: Linux-6.6.8-2-MANJARO-x86_64-with-glibc2.38 64 Bits, X11 UI
Graphics card: NVIDIA GeForce RTX 4090/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 545.29.06

Blender Version
Broken: 4.0.0, 4.0.2 and version: 4.1.0 Alpha, branch: main, commit date: 2024-01-12 15:34, hash: 17b32e1d0d71
Worked: 3.6.2, 3.6.7 LTS
Since Blender 4, baking the roughness of the Principled BSDF is affected by the base color. Now, roughness is baked correctly only if the base color is set to black. This also breaks baking addons. Tested with --factory-startup.

Exact steps for others to reproduce the error

In the default scene, switch to Material nodes editor
in the Principled BSDF, set roughness to 1.0 (so baking the roughness value should return a fully white image)
leave the base color as is (defaults to .8)
add a texture node and create an image texture
in the properties editor switch to Cycles, go to Bake settings, switch bake type to roughness
click Bake
check the result: the texture is grey with a value of .296 instead of white with a value of 1.0 like it was in Blender 3.6.7

**System Information** Operating system: Linux-6.6.8-2-MANJARO-x86_64-with-glibc2.38 64 Bits, X11 UI Graphics card: NVIDIA GeForce RTX 4090/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 545.29.06 **Blender Version** Broken: 4.0.0, 4.0.2 and version: 4.1.0 Alpha, branch: main, commit date: 2024-01-12 15:34, hash: `17b32e1d0d71` Worked: 3.6.2, 3.6.7 LTS Since Blender 4, baking the roughness of the Principled BSDF is affected by the base color. Now, roughness is baked correctly only if the base color is set to black. This also breaks baking addons. Tested with --factory-startup. **Exact steps for others to reproduce the error** - In the default scene, switch to Material nodes editor - in the Principled BSDF, set roughness to 1.0 (so baking the roughness value should return a fully white image) - leave the base color as is (defaults to .8) - add a texture node and create an image texture - in the properties editor switch to Cycles, go to Bake settings, switch bake type to roughness - click Bake - check the result: the texture is grey with a value of .296 instead of white with a value of 1.0 like it was in Blender 3.6.7

Georg K added the

labels 2024-01-13 04:44:32 +01:00

Jesse Yurkovich commented

2024-01-13 06:13:21 +01:00

Confirmed. This seems to have happened sometime between 2023-07-28 22206a159282 and 2023-08-15 5741a5d433cd.

Attached is a simple file, ready for a small and fast bake.

Confirmed. This seems to have happened sometime between 2023-07-28 `22206a159282` and 2023-08-15 `5741a5d433cd`. Attached is a simple file, ready for a small and fast bake.

bake.blend

888 KiB

Jesse Yurkovich added

and removed

labels 2024-01-13 06:13:33 +01:00

Jesse Yurkovich added