EEVEE macOS: visual glitching when using Tangent shader input on hair #91883

New Issue

RoyTheKoi · 2021-10-01T15:35:42+02:00

RoyTheKoi commented

2021-10-01 15:35:42 +02:00

System Information
Operating system: macOS Big Sur 11.2.3
Graphics card: AMD Radeon Pro 5500M 8 GB, Intel UHD Graphics 630 1536 MB

Blender Version
Broken: 3.0.0 Alpha, e81533b25e, master, 2021-09-28
Worked: Unknown

Short description of error
Attempting to use the "Tangent" shader input on hair with EEVEE results in visual glitching and smearing in the viewport:
EEVEE Hair Tangent Bug example.mov

Furthermore, if the tangent input is used in a node tree with any BSDF nodes, the hair will fail to render at all, appearing checkered as if it were using holdout instead:

I've tested on both Windows and macOS; only macOS is affected.

A similar bug occurs with the Parametric input, however it's slightly different so I will open another report for that one.

Exact steps for others to reproduce the error

Part one:

Add a particle system to the default cube, or any mesh
In the particle settings set the type to Hair
To visualise the hair more clearly: under Hair Shape, increase diameter scale to 0.1. Also, under Render Properties -> Hair, set the Hair Shape Type to "Strip"
Add a material to the mesh if it doesn't already have one
In the shader editor add a Geometry node
Connect the "Tangent" input to the Surface port on the material output node
Enter EEVEE Material Preview or Rendered mode and orbit the 3dview to see smearing and glitching
Part two:
Add a diffuse BSDF (or any BSDF) node
Connect the tangent input to any port on the BSDF node.
Render with F12. In the rendered image any hair strips appear checkered as if they were masked with holdout

Example blend file below. Note: if the hair doesn't show up, toggle "Regrow" or any other option in the particle settings.
EEVEE Hair Tangent Bug.blend

**System Information** Operating system: macOS Big Sur 11.2.3 Graphics card: AMD Radeon Pro 5500M 8 GB, Intel UHD Graphics 630 1536 MB **Blender Version** Broken: 3.0.0 Alpha, e81533b25e6b, master, 2021-09-28 Worked: Unknown **Short description of error** Attempting to use the "Tangent" shader input on hair with EEVEE results in visual glitching and smearing in the viewport: [EEVEE Hair Tangent Bug example.mov](https://archive.blender.org/developer/F10713517/EEVEE_Hair_Tangent_Bug_example.mov) Furthermore, if the tangent input is used in a node tree with any BSDF nodes, the hair will fail to render at all, appearing checkered as if it were using holdout instead: ![EEVEE Hair Tangent Bug.png](https://archive.blender.org/developer/F10713714/EEVEE_Hair_Tangent_Bug.png) ![EEVEE Hair Tangent Bug Shader Setup.png](https://archive.blender.org/developer/F10713737/EEVEE_Hair_Tangent_Bug_Shader_Setup.png) I've tested on both Windows and macOS; **only macOS is affected**. A similar bug occurs with the Parametric input, however it's slightly different so I will open another report for that one. **Exact steps for others to reproduce the error** Part one: 1. Add a particle system to the default cube, or any mesh 2. In the particle settings set the type to Hair 3. To visualise the hair more clearly: under Hair Shape, increase diameter scale to 0.1. Also, under Render Properties -> Hair, set the Hair Shape Type to "Strip" 4. Add a material to the mesh if it doesn't already have one 5. In the shader editor add a Geometry node 6. Connect the "Tangent" input to the Surface port on the material output node 7. Enter EEVEE Material Preview or Rendered mode and orbit the 3dview to see smearing and glitching Part two: 8. Add a diffuse BSDF (or any BSDF) node 9. Connect the tangent input to any port on the BSDF node. 10. Render with F12. In the rendered image any hair strips appear checkered as if they were masked with holdout Example blend file below. Note: if the hair doesn't show up, toggle "Regrow" or any other option in the particle settings. [EEVEE Hair Tangent Bug.blend](https://archive.blender.org/developer/F10713878/EEVEE_Hair_Tangent_Bug.blend)

RoyTheKoi commented

2021-10-01 15:35:42 +02:00

Added subscriber: @RoyTheKoi

Germano Cavalcante commented

2021-10-04 16:43:17 +02:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2021-10-04 16:43:17 +02:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Germano Cavalcante commented

2021-10-04 16:43:17 +02:00

I was unable to replicate the problem with macOS Big Sur (11.5.2) - ARM 64 Bits.
You mentioned 2 graphics cards, can you confirm which one the blender is using? You can see this information in system_info.txt generated in Help -> Save System Info.

It would also be helpful if you could test Blender with the other available gpu so we could be more accurate in detecting where the bug is.

I was unable to replicate the problem with `macOS Big Sur (11.5.2) - ARM 64 Bits`. You mentioned 2 graphics cards, can you confirm which one the blender is using? You can see this information in system_info.txt generated in `Help -> Save System Info`. It would also be helpful if you could test Blender with the other available gpu so we could be more accurate in detecting where the bug is.

RoyTheKoi commented

2021-10-04 17:04:32 +02:00

Perhaps the problem doesn't affect ARM macs. I'm on an Intel Macbook Pro 16inch that has both an integrated Intel gpu and a discrete (built in, not external) AMD gpu. Blender is using the AMD gpu based on system info, and I've confirmed this to be true by checking gpu activity in Activity Monitor.

I'm not aware of any way to switch the gpu used for EEVEE on a Macbook, is that possible?

Perhaps the problem doesn't affect ARM macs. I'm on an Intel Macbook Pro 16inch that has both an integrated Intel gpu and a discrete (built in, not external) AMD gpu. Blender is using the AMD gpu based on system info, and I've confirmed this to be true by checking gpu activity in Activity Monitor. I'm not aware of any way to switch the gpu used for EEVEE on a Macbook, is that possible?

Germano Cavalcante commented

2021-10-04 22:11:41 +02:00

Changed status from 'Needs User Info' to: 'Needs Developer To Reproduce'

Germano Cavalcante commented

2021-10-04 22:11:41 +02:00

Good thing the blender is using the AMD GPU, it's more efficient.
I did a little research and it seems that on the Mac it's a bit complicated to choose the GPU that an application uses.
This is the link I found: https://www.addictivetips.com/mac-os/switch-to-gpu-macos/

But maybe it's good to wait for the #eevee_viewport team to take a look. If I'm not mistaken they have a Mac available.

Good thing the blender is using the AMD GPU, it's more efficient. I did a little research and it seems that on the Mac it's a bit complicated to choose the GPU that an application uses. This is the link I found: https://www.addictivetips.com/mac-os/switch-to-gpu-macos/ But maybe it's good to wait for the #eevee_viewport team to take a look. If I'm not mistaken they have a Mac available.

RoyTheKoi commented

2021-10-08 12:26:25 +02:00

I was able to test on another Mac with just an Intel gpu, no AMD. The smearing is gone, as shown in the video below, although there is still some general glitchiness and the tangents are inverted in the viewport (they are correct when rendering with F12).

EEVEE_hair_tangent_bug_intel_gpu_video.mov

Here's the F12 render showing correct tangents:

OS: macOS Catalina 10.15.3.
GPU: Intel Iris Graphics 550 1536 MB

There are clearly still some graphical problems on this Mac, but the terrible smearing isn't there. I suspect that the smearing is related to the AMD gpu.

I also tested the Parametric input on the Geometry shader node as it was giving me issues on the AMD Mac. There weren't any visible issues on the Intel-only Mac. I'll open another bug report for that at some point; just thought I'd mention it here as the issues appear similar.

I was able to test on another Mac with just an Intel gpu, no AMD. The smearing is gone, as shown in the video below, although there is still some general glitchiness and the tangents are inverted in the viewport (they are correct when rendering with F12). [EEVEE_hair_tangent_bug_intel_gpu_video.mov](https://archive.blender.org/developer/F10873259/EEVEE_hair_tangent_bug_intel_gpu_video.mov) Here's the F12 render showing correct tangents: ![EEVEE_hair_tangent_bug_Intel_GPU_F12_render.png](https://archive.blender.org/developer/F10873592/EEVEE_hair_tangent_bug_Intel_GPU_F12_render.png) OS: macOS Catalina 10.15.3. GPU: Intel Iris Graphics 550 1536 MB There are clearly still some graphical problems on this Mac, but the terrible smearing isn't there. I suspect that the smearing is related to the AMD gpu. I also tested the Parametric input on the Geometry shader node as it was giving me issues on the AMD Mac. There weren't any visible issues on the Intel-only Mac. I'll open another bug report for that at some point; just thought I'd mention it here as the issues appear similar.

Philipp Oeser removed the

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EEVEE macOS: visual glitching when using Tangent shader input on hair #91883