Assigning multiple materials to object breaks subdivision in Blender 3.1.2 #98174

New Issue

Shaoqing Li · 2022-05-16T23:03:05+02:00

Shaoqing Li commented

2022-05-16 23:03:05 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71

Blender Version
Broken: version: 2.83.20, branch: master, commit date: 2022-04-19 16:00, hash: a56e2faeb7
Worked: (newest version of Blender that worked as expected)

Short description of error
Applying 2 Materials to an object when using mirror and subdivision causes the geometry of an object to break.

Exact steps for others to reproduce the error
Based on Default startup.

Create Sphere Primitive.
Delete Half the faces
Select some Faces and Apply a Material (Default)
Select some different faces (with some overlap) and apply second material (Default with edited colours)
Apply Mirror Modifier so it looks like a sphere again.
Apply Subdivision Surface Modifier.
Observe Geometry Breaks

Loading file in an older version of blender (2.8) the issue cannot be recreated.

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71 **Blender Version** Broken: version: 2.83.20, branch: master, commit date: 2022-04-19 16:00, hash: `a56e2faeb7` Worked: (newest version of Blender that worked as expected) **Short description of error** Applying 2 Materials to an object when using mirror and subdivision causes the geometry of an object to break. **Exact steps for others to reproduce the error** Based on Default startup. Create Sphere Primitive. Delete Half the faces Select some Faces and Apply a Material (Default) Select some different faces (with some overlap) and apply second material (Default with edited colours) Apply Mirror Modifier so it looks like a sphere again. Apply Subdivision Surface Modifier. Observe Geometry Breaks Loading file in an older version of blender (2.8) the issue cannot be recreated.

Shaoqing Li commented

2022-05-16 23:03:05 +02:00

Added subscriber: @Luna-7

Shaoqing Li commented

2022-05-16 23:05:06 +02:00

My example Blender file:
https://drive.google.com/file/d/1ps2qs6xywoPDKLxbbTfDonJYn4jqbgcl/view?usp=sharing

My example Blender file: https://drive.google.com/file/d/1ps2qs6xywoPDKLxbbTfDonJYn4jqbgcl/view?usp=sharing

Pratik Borhade commented

2022-05-17 06:18:52 +02:00

Added subscriber: @PratikPB2123

Pratik Borhade commented

2022-05-17 06:18:52 +02:00

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

Pratik Borhade commented

2022-05-17 06:18:52 +02:00

Hi, thanks for the report. Can you share screenshot to show how mesh appears in viewport?
I'm not seeing anything broken in 2.83.17 and latest 3.3 alpha.
Are you sure 2.83LTS is broken version? I'm seeing 3.1.2 in your file name and report header. probably same issue as in #96845 (Regression: GPU Subdivision with mirror/Array modifier shows artifacts)
Can you also check again in latest blender version?: https://builder.blender.org/download/daily

Hi, thanks for the report. Can you share screenshot to show how mesh appears in viewport? I'm not seeing anything broken in 2.83.17 and latest 3.3 alpha. Are you sure 2.83LTS is broken version? I'm seeing 3.1.2 in your file name and report header. probably same issue as in #96845 (Regression: GPU Subdivision with mirror/Array modifier shows artifacts) Can you also check again in latest blender version?: https://builder.blender.org/download/daily

Shaoqing Li commented

2022-05-18 16:39:21 +02:00

Hi Pratik, please check this video - I recorded my screen while I open this file "https://drive.google.com/file/d/1ps2qs6xywoPDKLxbbTfDonJYn4jqbgcl/view?usp=sharing" in 3 different versions of Blender (include the newest 3.3 alpha), please feel free to check:
https://youtu.be/xHygzfoFnfY

Hi Pratik, please check this video - I recorded my screen while I open this file "https://drive.google.com/file/d/1ps2qs6xywoPDKLxbbTfDonJYn4jqbgcl/view?usp=sharing" in 3 different versions of Blender (include the newest 3.3 alpha), please feel free to check: https://youtu.be/xHygzfoFnfY

Shaoqing Li commented

2022-05-18 16:40:45 +02:00

This file has no problem in both 2.83.17 and latest 3.3 alpha, the bug only existed in the blender 3.1.2 version as you can see in this screen recording: https://youtu.be/xHygzfoFnfY

Pratik Borhade commented

2022-05-18 17:40:45 +02:00

Hi, thanks for the information. Pretty sure this is same as- #96845 (Regression: GPU Subdivision with mirror/Array modifier shows artifacts)

the bug only existed in the blender 3.1.2 version

3.1 version is not maintained anymore. You can still fix this in 3.1 (and 3.1.2) by disabling GPU Subdivision: {nav Edit > Preferences > Viewport > Subdivision > GPU Subdivision}
Since latest versions are working correctly I'm closing this report.
Don't hesitate to comment if I've misunderstood anything

Hi, thanks for the information. Pretty sure this is same as- #96845 (Regression: GPU Subdivision with mirror/Array modifier shows artifacts) > the bug only existed in the blender 3.1.2 version 3.1 version is not maintained anymore. You can still fix this in 3.1 (and 3.1.2) by disabling GPU Subdivision: {nav Edit > Preferences > Viewport > Subdivision > GPU Subdivision} Since latest versions are working correctly I'm closing this report. Don't hesitate to comment if I've misunderstood anything

Pratik Borhade commented

2022-05-18 17:41:04 +02:00

Closed as duplicate of #96845

Pratik Borhade closed this issue

2022-05-18 17:41:04 +02:00

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Assigning multiple materials to object breaks subdivision in Blender 3.1.2 #98174