Cycles noise texture with high distortion differences between CPU and CUDA #72141

New Issue

CarlG · 2019-12-03T11:54:48+01:00

CarlG commented

2019-12-03 11:54:48 +01:00

System Information
Operating system: Windows-10-10.0.18362 64 Bits
Graphics card: Quadro M4000/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 411.63

Blender Version
Broken: version: 2.82 (sub 3), branch: master, commit date: 2019-11-30 17:33, hash: f1ac64921b
Worked: (optional)

Short description of error
Cycles appear to produce different random values for CUDA tiles and CPU tiles.

Exact steps for others to reproduce the error
Open TileBug_CUDA+CPU.blend and compare rendered view with rendered output.
Images of the bug in isolation.
CPU Only - Fine:

CUDA Only - Fine:

CPU + CUDA - Bugs out:

In addition, I had some even more strange artefacts in a real render.
The random effect is more subtle here, but it's there. But the other ones I can't really reproduce, not sure what is going on with that:

I can't update drivers, due to other software requiring certain certified drivers. Windows 10 is up to date.

**System Information** Operating system: Windows-10-10.0.18362 64 Bits Graphics card: Quadro M4000/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 411.63 **Blender Version** Broken: version: 2.82 (sub 3), branch: master, commit date: 2019-11-30 17:33, hash: `f1ac64921b` Worked: (optional) **Short description of error** Cycles appear to produce different random values for CUDA tiles and CPU tiles. **Exact steps for others to reproduce the error** Open [TileBug_CUDA+CPU.blend](https://archive.blender.org/developer/F8187126/TileBug_CUDA_CPU.blend) and compare rendered view with rendered output. Images of the bug in isolation. CPU Only - Fine: ![Report_CPU.jpg](https://archive.blender.org/developer/F8187163/Report_CPU.jpg) CUDA Only - Fine: ![Report_CUDA.jpg](https://archive.blender.org/developer/F8187165/Report_CUDA.jpg) CPU + CUDA - Bugs out: ![Report_CUDA+CPU.jpg](https://archive.blender.org/developer/F8187167/Report_CUDA_CPU.jpg) In addition, I had some even more strange artefacts in a real render. The random effect is more subtle here, but it's there. But the other ones I can't really reproduce, not sure what is going on with that: ![CUDA+CPU_Bug_Tiles_and_RandomLookupIssues.jpg](https://archive.blender.org/developer/F8187171/CUDA_CPU_Bug_Tiles_and_RandomLookupIssues.jpg) I can't update drivers, due to other software requiring certain certified drivers. Windows 10 is up to date.

CarlG commented

2019-12-03 11:54:48 +01:00

Added subscriber: @CarlG

blender-admin commented

2019-12-03 11:54:48 +01:00

#63716 was marked as duplicate of this issue

blender-admin commented

2019-12-03 11:54:48 +01:00

#69535 was marked as duplicate of this issue

blender-admin commented

2019-12-03 11:54:48 +01:00

#70501 was marked as duplicate of this issue

Germano Cavalcante commented

2019-12-04 16:15:15 +01:00

Added subscribers: @ColeMorris, @brecht, @zaster, @atomedia, @AaronSmithey, @mano-wii

Germano Cavalcante commented

2019-12-04 16:19:11 +01:00

It is also possible to reproduce the problem with OpenCL
I was able to reduce the material to this simple setup:

The file simplified:
TileBug_CUDA+CPU simplified.blend

It is also possible to reproduce the problem with OpenCL I was able to reduce the material to this simple setup: ![image.png](https://archive.blender.org/developer/F8189477/image.png) The file simplified: [TileBug_CUDA+CPU simplified.blend](https://archive.blender.org/developer/F8189476/TileBug_CUDA_CPU_simplified.blend)

Marcus Brock commented

2019-12-04 17:24:15 +01:00

Just to tidy things up... can somebody confirn, that the bug I have documented in #69535 (CPU + GPU render precision differences for small, far away area light) is the same one like this here? At least it looks pretty similar to me.

Germano Cavalcante commented

2019-12-04 19:27:58 +01:00

It is very similar, I will merge here to keep as a reference.
If when this is resolved, any of the other reports are not fixed, they will be reopened.

So far the similar reports are: #69535, #70501 and #70712

It is very similar, I will merge here to keep as a reference. If when this is resolved, any of the other reports are not fixed, they will be reopened. So far the similar reports are: #69535, #70501 and #70712

Germano Cavalcante commented

2019-12-04 19:28:15 +01:00

Added subscribers: @sozap, @lichtwerk

Harrison Weed commented

2020-01-29 15:05:47 +01:00

Added subscriber: @RigoLigo

Harrison Weed commented

2020-01-29 15:05:47 +01:00

This comment was removed by @RigoLigo

*This comment was removed by @RigoLigo*

Richard Antalik commented

2020-02-01 07:18:44 +01:00

Added subscribers: @filibis, @ZedDB, @SteffenD

Brecht Van Lommel commented

2020-05-14 18:30:43 +02:00

Removed subscribers: @SteffenD, @ZedDB, @filibis, @RigoLigo, @lichtwerk, @sozap, @AaronSmithey, @zaster, @ColeMorris

Brecht Van Lommel commented

2020-05-14 18:30:43 +02:00

Too many unrelated bugs were merged together here, trying to untangle them.

This particular issue will be difficult to solve as there will always be some difference between CPU and GPU, and with the extreme amount of distorion and successive nodes small differences can be amplified.

Too many unrelated bugs were merged together here, trying to untangle them. This particular issue will be difficult to solve as there will always be some difference between CPU and GPU, and with the extreme amount of distorion and successive nodes small differences can be amplified.

Brecht Van Lommel changed title from ~~Cycles CUDA+CPU results in different random output per rendering tile~~ to Cycles noise texture with high distortion differences between CPU and CUDA

2020-05-14 18:31:16 +02:00

Connor M. Denning commented

2022-03-22 04:43:17 +01:00

Added subscriber: @Connor-Denning

Philipp Oeser removed the

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Cycles noise texture with high distortion differences between CPU and CUDA #72141