Increased Sampling Noise when Rendering the World Background in Cycles. #78056

New Issue

Sam Walker · 2020-06-20T04:13:28+02:00

Sam Walker commented

2020-06-20 04:13:28 +02:00

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.19

Blender Version
Broken: version: 2.83.0, branch: master, commit date: 2020-06-03 14:38, hash: 211b6c29f7
Worked: 2.82a

Short description of error
There seems to be a differing amount of noise when rendering the world background between 2.82 and 2.83 in Cycles. I can't work out whether this noise is actually increased or if it's just different. In any case, it appears that the noise in 2.82 is more uniform and 'correct'. Tweaking the levels for better viewing (see the attached gifs) makes it appear as though in 2.82 the noise was perhaps more spread out and there were both lighter pixels and darker pixels, whereas in 2.83 the noise appears closer together and there are far fewer lighter pixels, seemingly making it more noticeable. Is this intended behaviour?

Exact steps for others to reproduce the error
Both gifs are of default cube renders in each version using identical settings @ 512 samples.

Default Scene 2.82a.blend
Default Scene 2.83.0.blend

**System Information** Operating system: Windows-10-10.0.18362-SP0 64 Bits Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.19 **Blender Version** Broken: version: 2.83.0, branch: master, commit date: 2020-06-03 14:38, hash: `211b6c29f7` Worked: 2.82a **Short description of error** There seems to be a differing amount of noise when rendering the world background between 2.82 and 2.83 in Cycles. I can't work out whether this noise is actually increased or if it's just different. In any case, it appears that the noise in 2.82 is more uniform and 'correct'. Tweaking the levels for better viewing (see the attached gifs) makes it appear as though in 2.82 the noise was perhaps more spread out and there were both lighter pixels and darker pixels, whereas in 2.83 the noise appears closer together and there are far fewer lighter pixels, seemingly making it more noticeable. Is this intended behaviour? ![Noise Difference_v1.gif](https://archive.blender.org/developer/F8632959/Noise_Difference_v1.gif) ![Noise Difference_v3.gif](https://archive.blender.org/developer/F8632973/Noise_Difference_v3.gif) **Exact steps for others to reproduce the error** Both gifs are of default cube renders in each version using identical settings @ 512 samples. [Default Scene 2.82a.blend](https://archive.blender.org/developer/F8651163/Default_Scene_2.82a.blend) [Default Scene 2.83.0.blend](https://archive.blender.org/developer/F8651162/Default_Scene_2.83.0.blend)

Sam Walker commented

2020-06-20 04:13:28 +02:00

Added subscriber: @Hexbob6

Germano Cavalcante commented

2020-06-23 20:36:45 +02:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2020-06-23 20:36:45 +02:00

512 samples don't bring that much noise in my case.
But I confirm that they are different. Although I can't say if it's more or less noiser.

The settings are the same and the release notes do not indicate what may have brought this change:
https://wiki.blender.org/wiki/Reference/Release_Notes/2.83/Cycles

512 samples don't bring that much noise in my case. But I confirm that they are different. Although I can't say if it's more or less noiser. The settings are the same and the release notes do not indicate what may have brought this change: https://wiki.blender.org/wiki/Reference/Release_Notes/2.83/Cycles

Brecht Van Lommel commented

2020-06-23 20:44:15 +02:00

Added subscriber: @brecht

Brecht Van Lommel commented

2020-06-23 20:44:15 +02:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Brecht Van Lommel commented

2020-06-23 20:44:15 +02:00

Please attach a .blend file to reproduce the problem.

Also ensure you have not enabled adaptive sampling, which does not exist in 2.82.

Please attach a .blend file to reproduce the problem. Also ensure you have not enabled adaptive sampling, which does not exist in 2.82.

Sam Walker commented

2020-06-28 13:55:30 +02:00

I have uploaded 2 test files, each are default scenes saved in their respective Blender versions. Adaptive Sampling isn't enabled in the 2.83.0 version. I've also tested the sampling differences between one of the Beta versions of 2.82 (c939b4df18), against 2.82a and found that the noise pattern is identical. I can upload references if needed.

I have uploaded 2 test files, each are default scenes saved in their respective Blender versions. Adaptive Sampling isn't enabled in the 2.83.0 version. I've also tested the sampling differences between one of the Beta versions of 2.82 (c939b4df18e9), against 2.82a and found that the noise pattern is identical. I can upload references if needed.

Brecht Van Lommel commented

2020-06-30 15:25:14 +02:00

Changed status from 'Needs User Info' to: 'Archived'

Brecht Van Lommel closed this issue

2020-06-30 15:25:14 +02:00

Brecht Van Lommel self-assigned this 2020-06-30 15:25:14 +02:00

Brecht Van Lommel commented

2020-06-30 15:25:14 +02:00

In these default scenes, all the noise is coming from dithering (this can be disabled in Output Properties > Post Processing).

This is an intentional change from 852cdd4. The goal of dithering is to approximate the color as close as possible, and the previous code was off by 0.5/255 which gives more lighter and darker pixels with the default background color, but with another background color it will be different again.

In these default scenes, all the noise is coming from dithering (this can be disabled in Output Properties > Post Processing). This is an intentional change from 852cdd4. The goal of dithering is to approximate the color as close as possible, and the previous code was off by 0.5/255 which gives more lighter and darker pixels with the default background color, but with another background color it will be different again.

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Increased Sampling Noise when Rendering the World Background in Cycles. #78056