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My goal is to bake a texture that has everything included except the diffuse of the material. This is what I tried: Combined bake with 'Diffuse' deselected. This however left out more than only the Diffuse. It left the Environment almost completely out. Also the emission of other objects felt less strong.

My temporary (slow) solution is doing the Combined bake with Diffuse. And then the Diffuse bake. After both are done I manually substract the Diffuse from the Combined (with my own program)...

Edit:

This is Combined Bake:
enter image description here

This is Combined Bake with 'Diffuse' deselected:
enter image description here

My cube is blue, my environment is red and an adjacent object is green. So apparently this test setup does give environment color in the bake..


@ sybog64
The green part is due to indirect lighting. This effect get omitted when using a black diffuse color (assuming the green object is part of the baked object). That is what I meant with scatter.


Back to my problem:

I think I misunderstood the concept of leaving the diffuse out..

So my (new) actual question is: How do I combine the Diffuse and the Combined (without diffuse) to get the Combined:

Diffuse:
enter image description here

Combined Bake with 'Diffuse' deselected:
enter image description here

Combined:
enter image description here

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  • $\begingroup$ If you want the diffuse component of your texture to be 0, set the diffuse component of your shader to pure black $\endgroup$
    – sybog64
    Nov 10, 2021 at 15:24
  • $\begingroup$ Thanks for the suggestion. But the scatter is removed in this way. And another reason why not to use this method is the unclear relationship to the end-result (mulitply / addition?) $\endgroup$
    – Arkylien
    Nov 10, 2021 at 16:01
  • $\begingroup$ I do not understand what you mean by scatter. That sounds to me like diffusion, which is what a diffuse pass is. Are you trying to remove the diffuse pass from the shader or remove diffuse bounces from the light information ? Could you provide a file and illustrations of what you're trying to achieve ? $\endgroup$
    – sybog64
    Nov 10, 2021 at 16:07
  • $\begingroup$ I edited my post $\endgroup$
    – Arkylien
    Nov 10, 2021 at 17:18
  • $\begingroup$ why your edit is commendable, I still fail to understand what you're technically trying to achieve. perhaps the use case you have could help clear it up. What are you going to use this texture for that you need to exclude the diffuse ? $\endgroup$
    – sybog64
    Nov 11, 2021 at 2:02

1 Answer 1

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First of all, let's clear some terms up:

Albedo : the physical color of a surface. It doesn't depend on light. Usually textures before they are baked or shaded. synonym for base color

Diffuse : Type of light bounce. It is part of the shading, not of the texture data.

This is the setup I'm working with:

render:
render


Blender's Combined baker will capture the exact tint of each texel if the camera angle was faced straight at it, including any gloss.

Blender's diffuse baker will capture the tint of each texel based only on the diffuse component of the object's material (it will use glossy bounces on other objects). This is basically for tinted lighting and shadows.

full diffuse:
diffuse

on a rough material, with not much specular detail, the diffuse and combined bake look pretty much identical.


Unchecking Color contribution from the diffuse baker will capture the shading as if the albedo was pure white.

lightmap:
only shading info


This can then be multiplied with any albedo to cheaply change the color of the object :

tinted lightmap:
diffuse * albedo


However, on non metallic materials, the glossy component is not multiplied with the albedo but added on top:

Tinted diffuse + glossy component :
diffuse * albedo + glossy


In conclusion, to get the lightmap, you want to bake the diffuse and uncheck color contribution:

bake settings

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    $\begingroup$ Great answer. I think this is the closest what I can come with a purely Blender based approach! Still, due to a weird game-engine I will have to post process my lightmaps $\endgroup$
    – Arkylien
    Nov 16, 2021 at 19:07

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