Using Sculpt Collision clips some of the hair curves in Rendered viewport shading #104704

New Issue

slwk1d · 2023-02-13T16:46:51+01:00

slwk1d commented

2023-02-13 16:46:51 +01:00

System Information
Operating system: Windows-10-10.0.19044-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 528.49

Blender Version
Broken: version: 3.5.0 Alpha, branch: main, commit date: 2023-02-13 01:17, hash: rB2a7440176e58
Worked: (newest version of Blender that worked as expected)

Short description of error
Enabling the new Sculpt Collision, combing some hair and then switching to render mode clips parts of the hair.

Exact steps for others to reproduce the error

Open attached file
Select CUDA device
Disable cage opacity property
Enable viewport rendering and comb curve hairs
[Add hair curves, add some hair, activate Sclupt Collisions, comb the hair, hit render viewport shading]
[attached .blend file (as simple as possible)]

**System Information** Operating system: Windows-10-10.0.19044-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 528.49 **Blender Version** Broken: version: 3.5.0 Alpha, branch: main, commit date: 2023-02-13 01:17, hash: `rB2a7440176e58` Worked: (newest version of Blender that worked as expected) **Short description of error** Enabling the new Sculpt Collision, combing some hair and then switching to render mode clips parts of the hair. ![Screenshot_2.png](/attachments/e86dbaea-9ebf-4c23-8499-925dc8c1955c) **Exact steps for others to reproduce the error** - Open attached file - Select CUDA device - Disable cage opacity property - Enable viewport rendering and comb curve hairs [Add hair curves, add some hair, activate Sclupt Collisions, comb the hair, hit render viewport shading] [attached .blend file (as simple as possible)]

bug.blend

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Screenshot_2.png

2.4 MiB

bug_video.mp4

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slwk1d added the

labels 2023-02-13 16:46:52 +01:00

Richard Antalik commented

2023-02-13 22:19:36 +01:00

Can't reproduce with same build and
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 526.98

Can't reproduce with same build and Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3060/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 526.98

slwk1d commented

2023-02-14 10:26:35 +01:00

Tried again with a new build on another machine, with factory settings, same result.
I made a video to show all the steps.

Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 965M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 528.24
3.5.0 Alpha, branch: main, commit date: 2023-02-14 02:26, hash: 46c34ba1f666

Tried again with a new build on another machine, with factory settings, same result. I made a video to show all the steps. Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 965M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 528.24 3.5.0 Alpha, branch: main, commit date: 2023-02-14 02:26, hash: `46c34ba1f666`

bug.mp4

20 MiB

Pratik Borhade commented

2023-02-15 16:45:38 +01:00

Unable to replicate either in current master (tried in uploaded file)

slwk1d commented

2023-02-16 10:13:35 +01:00

Unfortunately I was unable to find more specific causes so far. As shown in the video, after activating Collisions it doesn't happen immediately, but it does happen. I can only say to try again all the steps, especially increasing the size of the comb brush, putting it on projected mode, and change every once in a while the viewport zoom. It's very weird to me tough that on 2 different computers, different builds and factory settings, it still happenened to me...

slwk1d commented

2023-02-23 18:20:52 +01:00

I did a couple more tests just to confirm.
Steps-wise to reproduce the error, I couldn't find anything more specific, and I always used Blender's factory settings, enabling and disabling various options in the Preferences that might be the cause.
So again, to me the cause is the new Curve Collisions feature, and to be sure of this, I downloaded a build of 3.5 prior to its introduction (https://projects.blender.org/blender/blender/commit/b723a398f39) to make comparison videos.
Here are the 2 builds tested:

11 February, 03:43:26 - https://builder.blender.org/download/daily/archive/blender-3.5.0-alpha+main.343bb4a5a3fc-windows.amd64-release.zip
23 February, 03:32:16 - https://builder.blender.org/download/daily/blender-3.5.0-beta+v35.c760248fc5aa-windows.amd64-release.zip

As seen in the videos, in the build of 11 February the bug doesn't happen, in the 23 February does. I did these tests again using both my computers, and in both cases happened. Maybe if you guys couldn't reproduce it, it's a bug related to specific OS and/or graphics cards?

I did a couple more tests just to confirm. Steps-wise to reproduce the error, I couldn't find anything more specific, and I always used Blender's factory settings, enabling and disabling various options in the Preferences that might be the cause. So again, to me the cause is the new Curve Collisions feature, and to be sure of this, I downloaded a build of 3.5 prior to its introduction (https://projects.blender.org/blender/blender/commit/b723a398f39) to make comparison videos. Here are the 2 builds tested: * 11 February, 03:43:26 - https://builder.blender.org/download/daily/archive/blender-3.5.0-alpha+main.343bb4a5a3fc-windows.amd64-release.zip * 23 February, 03:32:16 - https://builder.blender.org/download/daily/blender-3.5.0-beta+v35.c760248fc5aa-windows.amd64-release.zip As seen in the videos, in the build of 11 February the bug doesn't happen, in the 23 February does. I did these tests again using both my computers, and in both cases happened. Maybe if you guys couldn't reproduce it, it's a bug related to specific OS and/or graphics cards?

23 February.mp4

31 MiB

11 February.mp4

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Pratik Borhade commented

2023-02-24 03:33:29 +01:00

@Slowwkidd , still unable to confirm locally.
BTW, my OS/GPU is:

**System Information**
Operating system: Windows-10-10.0.22000-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3050 Laptop GPU/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 512.78

I'll ask others whether they can reproduce this.

@Slowwkidd , still unable to confirm locally. BTW, my OS/GPU is: ``` **System Information** Operating system: Windows-10-10.0.22000-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3050 Laptop GPU/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 512.78 ``` I'll ask others whether they can reproduce this.

Philipp Oeser commented

2023-02-24 09:55:31 +01:00

Does this happen on GPU rendering only?
If so : Optix or CUDA?

Havent been able to repro here btw.

**System Information**
Operating system: Linux-6.1.6-200.fc37.x86_64-x86_64-with-glibc2.36 64 Bits
Graphics card: AMD Radeon Graphics (renoir, LLVM 15.0.6, DRM 3.49, 6.1.6-200.fc37.x86_64) AMD 4.6 (Core Profile) Mesa 22.3.3
version: 3.5.0 Beta, branch: blender-v3.5-release, commit date: 2023-02-23 20:30, hash: `f9f29eefc774`

Does this happen on GPU rendering only? If so : Optix or CUDA? Havent been able to repro here btw. ``` **System Information** Operating system: Linux-6.1.6-200.fc37.x86_64-x86_64-with-glibc2.36 64 Bits Graphics card: AMD Radeon Graphics (renoir, LLVM 15.0.6, DRM 3.49, 6.1.6-200.fc37.x86_64) AMD 4.6 (Core Profile) Mesa 22.3.3 version: 3.5.0 Beta, branch: blender-v3.5-release, commit date: 2023-02-23 20:30, hash: `f9f29eefc774` ```

slwk1d commented

2023-02-24 10:51:47 +01:00

Does this happen on GPU rendering only?
If so : Optix or CUDA?

@lichtwerk Definetely GPU rendering CUDA, on both the computers I tested. In fact, I just did a test to try switching from GPU to CPU while in viewport rendering, and as you can see in the video, it brings hair back, so it's related/happens only with GPU rendering.

> Does this happen on GPU rendering only? If so : Optix or CUDA? @lichtwerk Definetely GPU rendering CUDA, on both the computers I tested. In fact, I just did a test to try switching from GPU to CPU while in viewport rendering, and as you can see in the video, it brings hair back, so it's related/happens only with GPU rendering.

2023-02-24 10-45-28.mp4

5.4 MiB

Iliya Katushenock commented

2023-02-24 14:00:47 +01:00

Couldn't reproduce it.
System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 527.56
Version: 3.6.0 Alpha, branch: main, commit date: 2023-02-22 20:03, hash: e497a50aa207

Although I get another artifact, most likely it is not related to the report.

Couldn't reproduce it. **System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 527.56 Version: 3.6.0 Alpha, branch: main, commit date: 2023-02-22 20:03, hash: `e497a50aa207` --- Although I get another artifact, most likely it is not related to the report.

2023-02-24 15-58-38.mp4

12 MiB

slwk1d commented

2023-02-24 16:04:42 +01:00

@mod_moder to me that looks exactly like my report!
Do you see that at one point in your video, the hair gets clipped inside an invisible box?

If you saved the file (or try to do that again), try disabling the hair cage in the overlays/change to obejct mode while still in render preview mode. That's the clipping I'm talking about (putting a screenshot from one of my recent videos).

In your also case the whole object appears in another position, but that's I think is a matter of speed in calculating the position by the gpu.

@mod_moder to me that looks exactly like my report! Do you see that at one point in your video, the hair gets clipped inside an invisible box? ![clip.png](/attachments/67c4e72d-4590-4260-a912-caf18a6f92ec) If you saved the file (or try to do that again), try disabling the hair cage in the overlays/change to obejct mode while still in render preview mode. That's the clipping I'm talking about (putting a screenshot from one of my recent videos). ![Screenshot_5.png](/attachments/124ad421-707e-4016-bcea-b18ccc489493) In your also case the whole object appears in another position, but that's I think is a matter of speed in calculating the position by the gpu.

Screenshot_5.png

2.0 MiB

clip.png

191 KiB

Iliya Katushenock commented

2023-02-24 16:12:24 +01:00

@Slowwkidd This is not your report, because it is just an artifact of Cycles. This is even in default cube scene.

slwk1d commented

2023-02-24 16:23:43 +01:00

I don't understand what you mean, what's in the default cube scene? As shown in my previous video in the build pre-collision, combing and switching to viewport render does not create that artifact.