Rendering a scene without light: result is not completely black #73834

New Issue

Gaddhi · 2020-02-15T12:37:09+01:00

Gaddhi commented

2020-02-15 12:37:09 +01:00

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce RTX 2070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.19

Blender Version
Broken: version: 2.83 (sub 3), branch: master, commit date: 2020-02-14 23:40, hash: 92a56bbe6a
Worked: v 2.82

Short description of error
Rendering a scene without light results in a render, that is not completely black, but shows a dark noise.
This happens with Eevee, Cycles CUDA and Cycles OptiX

The dark noise not only appears in the Viewport but also when rendering the scene.

I would expect that the background of the scene is completely black (#000000), however it shows only a dark noise.

Attached is a comparison picture of the view after the described steps in v2.82 and v2.83

Exact steps for others to reproduce the error

Begin with default startup file
Switch "Viewport Shading" to "Display Render Preview"
"World properties" -> "Surface" -> Set "Strength" to 0.000

Thank you for having a look into this issue.

**System Information** Operating system: Windows-10-10.0.18362-SP0 64 Bits Graphics card: GeForce RTX 2070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.19 **Blender Version** Broken: version: 2.83 (sub 3), branch: master, commit date: 2020-02-14 23:40, hash: `92a56bbe6a` Worked: v 2.82 **Short description of error** Rendering a scene without light results in a render, that is not completely black, but shows a dark noise. This happens with Eevee, Cycles CUDA and Cycles OptiX The dark noise not only appears in the Viewport but also when rendering the scene. I would expect that the background of the scene is completely black (#000000), however it shows only a dark noise. Attached is a comparison picture of the view after the described steps in v2.82 and v2.83 ![blender-dark-noise.jpg](https://archive.blender.org/developer/F8341128/blender-dark-noise.jpg) **Exact steps for others to reproduce the error** 1. Begin with default startup file 2. Switch "Viewport Shading" to "Display Render Preview" 3. "World properties" -> "Surface" -> Set "Strength" to 0.000 Thank you for having a look into this issue.

Gaddhi commented

2020-02-15 12:37:09 +01:00

Added subscriber: @Gaddhi

blender-admin commented

2020-02-15 12:37:09 +01:00

#73903 was marked as duplicate of this issue

Pasang Bomjan commented

2020-02-15 14:01:26 +01:00

Added subscriber: @Pasang

Pasang Bomjan commented

2020-02-15 14:01:26 +01:00

I can confirm. 2.83 used to work fine a few days ago.

William Reynish commented

2020-02-15 16:17:27 +01:00

Added subscriber: @WilliamReynish

William Reynish commented

2020-02-15 16:17:27 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Brecht Van Lommel was assigned by William Reynish

2020-02-15 16:17:27 +01:00

William Reynish commented

2020-02-15 16:17:27 +01:00

Interestingly, I can confirm this while testing on macOS and Windows 10. Seems like a relatively high priority issue to me.

Brecht Van Lommel removed their assignment 2020-02-15 16:24:22 +01:00

Clément Foucault was assigned by Brecht Van Lommel

2020-02-15 16:24:22 +01:00

Brecht Van Lommel commented

2020-02-15 16:24:22 +01:00

Added subscriber: @brecht

Brecht Van Lommel commented

2020-02-15 16:24:22 +01:00

I'm assuming this is related to the recent color management refactor.

Gaddhi commented

2020-02-15 17:35:14 +01:00

A few additional notes:

This issue happens not only for the background, but also for any objects, that have a black color.
When the intended color is not black, but slightly brighter, the noise is still there, but it is more difficult to notice.

After compiling and testing a few versions of blender, I was able to pinpoint the introduction of this issue.
This issue was not present in 58cdab8b97
but in the following commit 804e90b42d

A few additional notes: - This issue happens not only for the background, but also for any objects, that have a black color. - When the intended color is not black, but slightly brighter, the noise is still there, but it is more difficult to notice. After compiling and testing a few versions of blender, I was able to pinpoint the introduction of this issue. This issue was not present in 58cdab8b9759dd59b55895f2f76b9624addbb324 but in the following commit 804e90b42d728ecb1073af8d0bae15a91b13a469

Clément Foucault commented

2020-02-15 20:51:15 +01:00

Likely to be fixed by D6850

Likely to be fixed by [D6850](https://archive.blender.org/developer/D6850)

Gaddhi commented

2020-02-15 21:49:14 +01:00

@fclem Thank you for pointing me to this patch. I will have a look at it.

Evan Wilson commented

2020-02-15 22:03:39 +01:00

Added subscriber: @EAW

Evan Wilson commented

2020-02-15 22:03:39 +01:00

@Gaddhi Without the patch, I have found that a dithering value of around 0.1 works well for my use case, compared to the default 1 before. If you want pure black you have to set dithering to 0

Gaddhi commented

2020-02-16 09:31:58 +01:00

I did apply D6850 to the current master-branch and tested it: It solved this problem.
@EAW Thank you for pointing out this workaround.

I did apply [D6850](https://archive.blender.org/developer/D6850) to the current master-branch and tested it: It solved this problem. @EAW Thank you for pointing out this workaround.

Evan Wilson commented

2020-02-17 03:51:47 +01:00

Added subscriber: @JustinWebster