Overlapping Volumes broken in Cycles, GPU only (possible regression) #96381

New Issue

Thomas Kole · 2022-03-12T21:21:32+01:00

Thomas Kole commented

2022-03-12 21:21:32 +01:00

System Information
Operating system: Linux-4.15.0-162-generic-x86_64-with-glibc2.27 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.91.03

Blender Version
Broken: version: 3.1.0, branch: master, commit date: 2022-03-08 18:16, hash: c77597cd0e
Worked: Unknown, possibly 3.0
Caused by 74afc86d4b

In my project I have a large landscape, with two volumes.
One for the fog, which is just a vertical gradient, and the other for clouds.
It looks like this:

However, since 3.1, I noticed my fog being broken.
Instead, it's now rendering these vertical lines:

Before	After

I've tried all sorts of things, but I can't really work around this one.
It only appears when rendering on the GPU (a GTX1070 in my case, Linux)

	Fog + Clouds	Fog	Clouds
GPU
CPU

As you can see, weird vertical lines show up.

I recreated the scenario in a separate scene, for easy reproduction :)
I hope this is reproducible on your end, I don't have extra machines to test it on.
BrokenOverlappingVolumes.blend

**System Information** Operating system: Linux-4.15.0-162-generic-x86_64-with-glibc2.27 64 Bits Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 460.91.03 **Blender Version** Broken: version: 3.1.0, branch: master, commit date: 2022-03-08 18:16, hash: `c77597cd0e` Worked: Unknown, possibly 3.0 Caused by 74afc86d4b In my project I have a large landscape, with two volumes. One for the fog, which is just a vertical gradient, and the other for clouds. It looks like this: ![image.png](https://archive.blender.org/developer/F12923575/image.png) However, since 3.1, I noticed my fog being broken. Instead, it's now rendering these vertical lines: | Before | After | -- | -- | | ![image.png](https://archive.blender.org/developer/F12923584/image.png) | ![image.png](https://archive.blender.org/developer/F12923582/image.png) I've tried all sorts of things, but I can't really work around this one. It only appears when rendering on the GPU (a GTX1070 in my case, Linux) | | Fog + Clouds | Fog | Clouds | -- | -- | -- | -- | | GPU | ![image.png](https://archive.blender.org/developer/F12923567/image.png) | ![image.png](https://archive.blender.org/developer/F12923571/image.png) | ![image.png](https://archive.blender.org/developer/F12923573/image.png) | CPU | ![image.png](https://archive.blender.org/developer/F12923563/image.png) | ![image.png](https://archive.blender.org/developer/F12923561/image.png) | ![image.png](https://archive.blender.org/developer/F12923565/image.png) As you can see, weird vertical lines show up. ![image.png](https://archive.blender.org/developer/F12923569/image.png) I recreated the scenario in a separate scene, for easy reproduction :) I hope this is reproducible on your end, I don't have extra machines to test it on. [BrokenOverlappingVolumes.blend](https://archive.blender.org/developer/F12923587/BrokenOverlappingVolumes.blend)

Thomas Kole commented

2022-03-12 21:21:32 +01:00

Added subscriber: @ThomasKole

Thomas Kole commented

2022-03-12 21:35:43 +01:00

I think I can confirm that it is a regression:

3.0.0	3.1.0

3.1.0 shows the vertical lines.

This time on Windows (again, CUDA with a GTX1070)

I think I can confirm that it is a regression: | 3.0.0 | 3.1.0 | -- | -- | | ![image.png](https://archive.blender.org/developer/F12923603/image.png) | ![image.png](https://archive.blender.org/developer/F12923601/image.png) 3.1.0 shows the vertical lines. ![image.png](https://archive.blender.org/developer/F12923608/image.png) This time on Windows (again, CUDA with a GTX1070)

Alaska commented

2022-03-13 01:13:49 +01:00

Added subscriber: @Alaska

Alaska commented

2022-03-13 01:13:49 +01:00

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

Alaska commented

2022-03-13 01:13:49 +01:00

I can confirm this issue with CUDA and a similar, but different issue on OptiX with the setup below. I will investigate and try to find the culprit commit.

System Information
Operating system: Linux-5.16.0-3-amd64-x86_64-with-glibc2.33 64 Bits
Graphics card: NVIDIA GeForce RTX 3060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.54
Blender version: 3.2.0 Alpha, branch: master, commit date: 2022-03-11 20:57, hash: f19582ebf4

I can confirm this issue with CUDA and a similar, but different issue on OptiX with the setup below. I will investigate and try to find the culprit commit. **System Information** Operating system: Linux-5.16.0-3-amd64-x86_64-with-glibc2.33 64 Bits Graphics card: NVIDIA GeForce RTX 3060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 510.54 Blender version: 3.2.0 Alpha, branch: master, commit date: 2022-03-11 20:57, hash: `f19582ebf4`

Alaska commented

2022-03-13 03:50:16 +01:00

Added subscribers: @leesonw, @brecht