Possible NaNs with refractive BSDF #50700

New Issue

Ivan Malek · 2017-02-16T13:02:41+01:00

Ivan Malek commented

2017-02-16 13:02:41 +01:00

System Information
i7 3930k
40GB RAM
Nvidia GeForce GTX660 (driver version 21.21.13.7653)
windows 10 pro, 64-bit

Blender Version
2.78a e8299c8

Short description of error
cycles renders artifacts, that look like NaN errors: see image

Exact steps for others to reproduce the error
open scene NaN_bug.blend, set viewport to "Rendered" or press f12 to render, while it's cooking, these white dots start to pop up

**System Information** i7 3930k 40GB RAM Nvidia GeForce GTX660 (driver version 21.21.13.7653) windows 10 pro, 64-bit **Blender Version** 2.78a e8299c8 **Short description of error** cycles renders artifacts, that look like NaN errors: see image ![001_NaN.png](https://archive.blender.org/developer/F486543/001_NaN.png) **Exact steps for others to reproduce the error** open scene [NaN_bug.blend](https://archive.blender.org/developer/F486545/NaN_bug.blend), set viewport to "Rendered" or press f12 to render, while it's cooking, these white dots start to pop up

Ivan Malek commented

2017-02-16 13:02:41 +01:00

Changed status to: 'Open'

Ivan Malek commented

2017-02-16 13:02:41 +01:00

Added subscriber: @IvanMalek

Thomas Dinges commented

2017-02-18 22:38:09 +01:00

Added subscribers: @Sergey, @ThomasDinges

Thomas Dinges commented

2017-02-18 22:38:09 +01:00

Doesn't look like a bug, just reflections from the lamp. Disable MIS for the lamp and the birght spots go away.

@Sergey Can you confirm?

Doesn't look like a bug, just reflections from the lamp. Disable MIS for the lamp and the birght spots go away. @Sergey Can you confirm?

Sergey Sharybin self-assigned this 2017-02-23 11:42:20 +01:00

Sergey Sharybin commented

2017-02-23 11:42:20 +01:00

Added subscriber: @brecht

Sergey Sharybin commented

2017-02-23 11:42:20 +01:00

The noise is coming from caustics i think. Usually using Filter Glossy will help, but it has no effect on Sharp distribution. Doing something like D2416 will help here.

At least that's what i see from quick investigation and might be wrong.

In any case, unsolvable noise is not a good thing anyway and disabling MIS is not really a solution in real production scenes.

Maybe @brecht can throw some ideas here as well :)

The noise is coming from caustics i think. Usually using Filter Glossy will help, but it has no effect on Sharp distribution. Doing something like [D2416](https://archive.blender.org/developer/D2416) will help here. At least that's what i see from quick investigation and might be wrong. In any case, unsolvable noise is not a good thing anyway and disabling MIS is not really a solution in real production scenes. Maybe @brecht can throw some ideas here as well :)

Brecht Van Lommel commented

2017-02-24 00:45:14 +01:00

I think D2416 would be good for this case.

The other workaround is to use the transparent shadows trick, which might be good to add as a builtin feature of the glass BSDF node:
https://docs.blender.org/manual/en/dev/render/cycles/optimizations/reducing_noise.html#glass-and-transparent-shadows

I think [D2416](https://archive.blender.org/developer/D2416) would be good for this case. The other workaround is to use the transparent shadows trick, which might be good to add as a builtin feature of the glass BSDF node: https://docs.blender.org/manual/en/dev/render/cycles/optimizations/reducing_noise.html#glass-and-transparent-shadows

Sergey Sharybin commented

2017-02-27 12:45:43 +01:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2017-02-27 12:45:43 +01:00

Sergey Sharybin commented

2017-02-27 12:45:43 +01:00

I've fixed some issues in D2416 and committed it now. So now there is a way to make his file to be less noisy.

Surely having some built-in feature for transparent shadow for BSDF will be interesting, but think that's out of the scope of this report.

I've fixed some issues in [D2416](https://archive.blender.org/developer/D2416) and committed it now. So now there is a way to make his file to be less noisy. Surely having some built-in feature for transparent shadow for BSDF will be interesting, but think that's out of the scope of this report.

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Possible NaNs with refractive BSDF #50700