Cycles Baking Ignores Exposure #75259

New Issue

Jonathan Lampel · 2020-04-01T02:40:49+02:00

Jonathan Lampel commented

2020-04-01 02:40:49 +02:00

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 432.00

Blender Version
Broken: version: 2.83 (sub 9), branch: master, commit date: 2020-03-17 14:02, hash: b852db57ba

Short description of error
Cycles baking does not take the scene exposure into account. This omission makes it impossible to bake scenes with strong or weak lights whose values need to match another file, reference, or scene.

Exact steps for others to reproduce the error

Open baking_exposure.blend
Note light strength and exposure values
Click Bake

Resulting texture:

Expected texture:

File:
baking_exposure.blend

**System Information** Operating system: Windows-10-10.0.18362-SP0 64 Bits Graphics card: GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 432.00 **Blender Version** Broken: version: 2.83 (sub 9), branch: master, commit date: 2020-03-17 14:02, hash: `b852db57ba` **Short description of error** Cycles baking does not take the scene exposure into account. This omission makes it impossible to bake scenes with strong or weak lights whose values need to match another file, reference, or scene. **Exact steps for others to reproduce the error** 1. Open baking_exposure.blend 2. Note light strength and exposure values 3. Click Bake Resulting texture: ![bake_01.png](https://archive.blender.org/developer/F8440139/bake_01.png) Expected texture: ![bake_02.png](https://archive.blender.org/developer/F8440141/bake_02.png) File: [baking_exposure.blend](https://archive.blender.org/developer/F8440143/baking_exposure.blend)

Jonathan Lampel commented

2020-04-01 02:40:49 +02:00

Added subscriber: @JonathanLampel-4

Philip Holzmann commented

2020-04-01 12:19:44 +02:00

Added subscriber: @Foaly

Philip Holzmann commented

2020-04-01 12:19:44 +02:00

I think this is the intended behavior.

Applying the scene Color Management would be wrong.
Especially if you have something like the Filmic view transform set.

Adding an extra exposure setting to the bake panel would be possible.

Right now, I suggest you bake to a 32 bit float texture.

I think this is the intended behavior. Applying the scene Color Management would be wrong. Especially if you have something like the Filmic view transform set. Adding an extra exposure setting to the bake panel would be possible. Right now, I suggest you bake to a 32 bit float texture.

Richard Antalik commented

2020-04-01 13:27:27 +02:00

Added subscriber: @iss

Richard Antalik commented

2020-04-01 13:27:27 +02:00

I agree with @Foaly, this is working as intended.

But when I baked to 32 bit texture and render, the color was quite a bit off. Unless I did something wrong. So there may be a bug in this use-case, but I am not sure.

I agree with @Foaly, this is working as intended. But when I baked to 32 bit texture and render, the color was quite a bit off. Unless I did something wrong. So there may be a bug in this use-case, but I am not sure.

Jonathan Lampel commented

2020-04-01 17:35:06 +02:00

Applying the scene Color Management would be wrong.
Especially if you have something like the Filmic view transform set.

This is interesting, because you're totally right that for things like AO, it's wrong to apply color management since we need those pure whites and blacks. Same goes for the Shadow, Normal, UV, Roughness, and Emission.

For Environment, Diffuse, Glossy, and Subsurface though, it seems to be appropriate to apply color management or else the bake appears broken. Here's an example with a very normal light source, no exposure change, and an poor result:

> Applying the scene Color Management would be wrong. > Especially if you have something like the Filmic view transform set. This is interesting, because you're totally right that for things like AO, it's wrong to apply color management since we need those pure whites and blacks. Same goes for the Shadow, Normal, UV, Roughness, and Emission. For Environment, Diffuse, Glossy, and Subsurface though, it seems to be appropriate to apply color management or else the bake appears broken. Here's an example with a very normal light source, no exposure change, and an poor result: ![image.png](https://archive.blender.org/developer/F8441661/image.png)

Philip Holzmann commented

2020-04-02 17:55:28 +02:00

@JonathanLampel-4 In what sense is it broken? If you used 32 bit float textures, it should be ok.
If you plug in the result of a diffuse bake into an Emission shader (with strength 1.0), it should show the exact same result as if you just rendered with the original shader (disregarding specular).
Always applying the view transform would destroy that.

If you really want to apply the view transform, you can:

Bake to a float texture
Click Image > Save As
Choose image type and check Save As Render

This will apply the view transform on saving.

Note that I noticed a bug here as well:
Sometimes Blender immediately reloads the just-saved file and therefore applies the view transform in the image editor as well.
In other cases, the image will stay untransformed in the editor.
I suspect this has to do with File > External Data > Automatically Pack Into .blend being checked.

@JonathanLampel-4 In what sense is it broken? If you used 32 bit float textures, it should be ok. If you plug in the result of a diffuse bake into an Emission shader (with strength 1.0), it should show the exact same result as if you just rendered with the original shader (disregarding specular). Always applying the view transform would destroy that. If you really want to apply the view transform, you can: 1. Bake to a float texture 2. Click *Image* > *Save As* 3. Choose image type and check **Save As Render** This will apply the view transform on saving. Note that I noticed a bug here as well: Sometimes Blender immediately reloads the just-saved file and therefore applies the view transform in the image editor as well. In other cases, the image will stay untransformed in the editor. I suspect this has to do with *File* > *External Data* > *Automatically Pack Into .blend* being checked.

Jonathan Lampel commented

2020-04-03 01:06:21 +02:00

Whoa! Save As Render is exactly what I was looking for then. Thank you! Still seems like a strange workflow, but I can get the intended result this way. I'll close this out and tag it as not a bug. Thanks again!