Set Material Index node does not work on some GN-created geometry #112372

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opened 2023-09-14 13:21:28 +02:00 by Ludvik Koutny · 5 comments

Ludvik Koutny commented

2023-09-14 13:21:28 +02:00

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System Information
Operating system: Windows-10-10.0.22621-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 537.13

Blender Version
Broken: version: 3.6.2, branch: blender-v3.6-release, commit date: 2023-08-16 16:43, hash: e53e55951e7a
Worked: Never.

Short description of error
The scene contains 3 objects:

Mesh object with GN which creates Mesh Cube primitive
Curve object with GN which creates Mesh Cube primitive
Curve object with GN which creates geometry using Curve to Mesh node

All 3 objects have their Material linked to Object, not Object Data

The Set Material Index node works on 1. and 2. but does not work on 3.

Exact steps for others to reproduce the error

Open the attached blender file: curvematerialbug.blend
Check Geometry Nodes setups on all 3 objects
Result: Set Material Index Node does not work on Geometry generated by Curve to Mesh node.
Expected: Set material Index Node works on any geometry.

**System Information** Operating system: Windows-10-10.0.22621-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 537.13 **Blender Version** Broken: version: 3.6.2, branch: blender-v3.6-release, commit date: 2023-08-16 16:43, hash: `e53e55951e7a` Worked: Never. **Short description of error** The scene contains 3 objects: 1. Mesh object with GN which creates Mesh Cube primitive 2. Curve object with GN which creates Mesh Cube primitive 3. Curve object with GN which creates geometry using Curve to Mesh node All 3 objects have their Material linked to Object, not Object Data The Set Material Index node works on 1. and 2. but does not work on 3. **Exact steps for others to reproduce the error** 1. Open the attached blender file: [curvematerialbug.blend](/attachments/40ef2a4b-d397-4b99-8154-5b4be2ea9a6b) 2. Check Geometry Nodes setups on all 3 objects Result: Set Material Index Node does not work on Geometry generated by Curve to Mesh node. Expected: Set material Index Node works on any geometry.

curvematerialbug.blend

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Ludvik Koutny added the

labels 2023-09-14 13:21:29 +02:00

Iliya Katushenock added the

Nodes & Physics

labels 2023-09-14 13:40:13 +02:00

Iliya Katushenock changed title from ~~Set Material Index node does not work on some GN-created geometry~~ to Geometry Nodes: Curve Object materials are not used by Mesh material indices

2023-09-14 13:46:17 +02:00

Iliya Katushenock added

Nodes & Physics

and removed

Nodes & Physics

labels 2023-09-14 13:46:29 +02:00

Ludvik Koutny commented

2023-09-14 13:53:49 +02:00

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@mod_moder
I think the new name is more confusing. It implies that the problem is with curve objects, which is not true. I've specifically put example of a scene object which is a curve object, but the material works there. The problem is that some geometries generated by GN work with material indices, while others don't. The problem is not that the parent object type is curve, and not a mesh.

If you rename bug reports to worse names it may reduce the chance of responsible developer actually picking it up.

@mod_moder I think the new name is more confusing. It implies that the problem is with curve objects, which is not true. I've specifically put example of a scene object which is a curve object, but the material works there. The problem is that some geometries generated by GN work with material indices, while others don't. The problem is not that the parent object type is curve, and not a mesh. If you rename bug reports to worse names it may reduce the chance of responsible developer actually picking it up.

Iliya Katushenock changed title from ~~Geometry Nodes: Curve Object materials are not used by Mesh material indices~~ to Geometry Nodes: Uninitialized materials

2023-09-14 13:55:46 +02:00

Iliya Katushenock self-assigned this 2023-09-14 13:55:50 +02:00

Ludvik Koutny changed title from ~~Geometry Nodes: Uninitialized materials~~ to Set Material Index node does not work on some GN-created geometry

2023-09-14 14:22:48 +02:00

Ludvik Koutny commented

2023-09-14 14:23:34 +02:00

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Please just leave the title as is and let whoever claims the report to change it? I really think since this is a bug report, it should be more informative than "Geometry Nodes: Uninitialized materials". That doesn't really explain what the report is about.

EDIT: Nevermind, I thought you just triaged it. Didn't know you actually claimed it. In that case, use whatever name you need. I will revert it.

Please just leave the title as is and let whoever claims the report to change it? I really think since this is a bug report, it should be more informative than "Geometry Nodes: Uninitialized materials". That doesn't really explain what the report is about. EDIT: Nevermind, I thought you just triaged it. Didn't know you actually claimed it. In that case, use whatever name you need. I will revert it.

Ludvik Koutny changed title from ~~Set Material Index node does not work on some GN-created geometry~~ to Geometry Nodes: Uninitialized materials

2023-09-14 14:49:46 +02:00

Hans Goudey changed title from ~~Geometry Nodes: Uninitialized materials~~ to Set Material Index node does not work on some GN-created geometry

2023-09-14 18:40:02 +02:00

Iliya Katushenock referenced a pull request that will close this issue

2023-09-15 11:23:45 +02:00

Fix #112372: Object materials ignored without geometry material slots #112408

Iliya Katushenock referenced this issue

2023-10-14 09:38:30 +02:00

Volume-type geometries always seem to use the object material while mesh primitives are unpredictable #113712

Germano Cavalcante referenced this issue

2023-10-16 17:35:19 +02:00

Volume-type geometries always seem to use the object material while mesh primitives are unpredictable #113712

Ludvik Koutny commented

2024-03-27 11:45:53 +01:00

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This issue is still present in Blender 4.1. Any geometry created purely in Geometry Nodes can't have materials simply assigned in the Materials Properties panel, and has to be assigned in Geometry Nodes only. This makes it impossible to create GN assets users can assign material with ease, without having to open and mess with the geometry node tree.

Unlike Blender 4.0, the workaround of joining the GN created geometry with base object geometry and then deleting the base object geometry to get the mesh material no longer works.

So while in 4.0, this was broken and there was a workaround, in 4.1 it is still broken, but there's no longer a workaround.

This issue is still present in Blender 4.1. Any geometry created purely in Geometry Nodes can't have materials simply assigned in the Materials Properties panel, and has to be assigned in Geometry Nodes only. This makes it impossible to create GN assets users can assign material with ease, without having to open and mess with the geometry node tree. Unlike Blender 4.0, the workaround of joining the GN created geometry with base object geometry and then deleting the base object geometry to get the mesh material no longer works. So while in 4.0, this was broken and there was a workaround, in 4.1 it is still broken, but there's no longer a workaround.

Doeke commented

2024-05-02 10:51:16 +02:00

Just to add to the conversation. Working with materials in GN is non intuitive.
Here some more things, everything listed below is on a object that has two material slots:

Something like this will never work:

When we join with the original object it will:

If we have the order wrong in the join geometry then it doesn't work cause the plane does donates it's default material.

If we don't want to original mesh but do want to use the material slots we have to delete the geometry, but not use mode "all" cause then it deletes the material slots.

I hope this helps in some way.

Just to add to the conversation. Working with materials in GN is non intuitive. Here some more things, everything listed below is on a object that has two material slots: ![mat_01.png](/attachments/56e1c699-a43a-4ee2-8a8b-219a6a937b8e) Something like this will never work: ![mat_02.png](/attachments/8c59a759-bdc2-42a5-ad81-639a3cf482e7) When we join with the original object it will: ![mat_03.png](/attachments/d32f6229-523a-489a-a3a6-f989c0f6d99e) If we have the order wrong in the join geometry then it doesn't work cause the plane does donates it's default material. ![mat_04.png](/attachments/a79ed46b-2d38-440f-a861-eb2ef4485dca) If we don't want to original mesh but do want to use the material slots we have to delete the geometry, but not use mode "all" cause then it deletes the material slots. ![mat_05.png](/attachments/d7af0b02-f3e7-4aef-a2c4-147f3fcbf8d4) I hope this helps in some way.

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Iliya Katushenock commented

2024-05-02 14:36:18 +02:00

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@clankill3r For help using Blender, please try one of the community websites: https://www.blender.org/community/

@clankill3r For help using Blender, please try one of the community websites: https://www.blender.org/community/

Doeke referenced this issue

2024-05-02 16:49:10 +02:00

Material Bug in EEVEE-Next #121332

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