alpha does not contribute to adaptive sampling noise treshold #83493

New Issue

thomas pahler · 2020-12-07T11:02:47+01:00

thomas pahler commented

2020-12-07 11:02:47 +01:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 457.51

Blender Version
Broken: version: 2.91.0, branch: master, commit date: 2020-11-25 08:34, hash: 0f45cab862
Worked: i dont think it ever worked

Short description of error
when rendering with adaptive sampling enabled, the noise treshold does not seem to be affected by a noisy alpha channel.

this is most visible on shadow catchers: since their rgb is always black, they are always rendered with "Min Samples", as soon as adaptive sampling is enabled.
even though the alpha channel is still very noisy, it stops rendering additional samples.

Exact steps for others to reproduce the error
shadowCatcherNoise.blend

open file
render samples at 64-512 samples
when adaptive sampling is enabled, the shadow will remain very noisy. when adaptive sampling is disabled, the shadow will be smooth

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1080/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 457.51 **Blender Version** Broken: version: 2.91.0, branch: master, commit date: 2020-11-25 08:34, hash: `0f45cab862` Worked: i dont think it ever worked **Short description of error** when rendering with adaptive sampling enabled, the noise treshold does not seem to be affected by a noisy alpha channel. this is most visible on shadow catchers: since their rgb is always black, they are always rendered with "Min Samples", as soon as adaptive sampling is enabled. even though the alpha channel is still very noisy, it stops rendering additional samples. **Exact steps for others to reproduce the error** [shadowCatcherNoise.blend](https://archive.blender.org/developer/F9487852/shadowCatcherNoise.blend) - open file - render samples at 64-512 samples - when adaptive sampling is enabled, the shadow will remain very noisy. when adaptive sampling is disabled, the shadow will be smooth

thomas pahler commented

2020-12-07 11:02:47 +01:00

Added subscriber: @thomason1005

thomas pahler changed title from ~~alpha does not contribute ot adaptive sampling noise treshold~~ to alpha does not contribute to adaptive sampling noise treshold

2020-12-07 11:03:01 +01:00

thomas pahler commented

2020-12-07 11:19:07 +01:00

noisy alpha on shadow catcher (512 samples, adaptive):

smooth alpha (512 samples, adaptive disabled):

example file:
shadowCatcherNoise.blend

noisy alpha on shadow catcher (512 samples, adaptive): ![Screenshot 2020-12-07 111703.png](https://archive.blender.org/developer/F9487853/Screenshot_2020-12-07_111703.png) smooth alpha (512 samples, adaptive disabled): ![Screenshot 2020-12-07 111832.png](https://archive.blender.org/developer/F9487860/Screenshot_2020-12-07_111832.png) example file: [shadowCatcherNoise.blend](https://archive.blender.org/developer/F9487852/shadowCatcherNoise.blend)

Richard Antalik commented

2020-12-10 15:11:45 +01:00

Added subscriber: @iss

Richard Antalik commented

2020-12-10 15:11:45 +01:00

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

Richard Antalik commented

2020-12-10 15:11:45 +01:00

I guess this is feature request technically, but it looks like it could be implemented easily.

Though when I just added alpha to stopping error caclulation, it rendered even very dark area with max samples. But I barely know what I am doing.

I guess this is feature request technically, but it looks like it could be implemented easily. Though when I just added alpha to stopping error caclulation, it rendered even very dark area with max samples. But I barely know what I am doing.

Philipp Oeser removed the

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alpha does not contribute to adaptive sampling noise treshold #83493