Eevee Viewport Z-Fighting different if affected objects are in different collections #129330

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Cedric Steiert · 2024-10-22T17:38:44+02:00

Cedric Steiert commented

2024-10-22 17:38:44 +02:00

System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3080 Ti/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 552.44

Blender Version
Broken: version: 4.2.3 LTS, branch: blender-v4.2-release, commit date: 2024-10-14 15:20, hash: 0e22e4fcea03
Broken: version: 4.3.0 Beta, branch: blender-v4.3-release, commit date: 2024-10-21 16:47, hash: 5fff95f5193e
Worked: (newest version of Blender that worked as expected)

Short description of error
The Z-Fighting in attached video is different if the affected object (in video it's the ground plane) gets moved into another collection. To be more precise it is worse if fighting objects A and B are in the same collection and better if they are in different collections. When in different collections the z-fighting doesn't change anymore if collections change, as long as they are not in the same collection.

This behaviour (at least in my opinion) is a discrepancy to the docs, which suggest only a organizational relationship exists.

https://docs.blender.org/manual/en/latest/scene_layout/collections/collections.html:

Objects can be grouped together without any kind of transformation relationship (unlike parenting). Collections are used to just logically organize your scene, or to facilitate one-step appending or linking between files or across scenes.

I don't know why this difference of collection relationship happens, but it's kind of annyoing. At first i thought it's the viewport rerendering, but then the visual appearance of the z-fighting would be different with each move of the object into a different collection, however the result is the same no matter if in collection A or B as long as not in Main.

Exact steps for others to reproduce the error

Open attached file z-fighting-bug.blend
it should be in viewport shading material preview
result (ground in Main):
move ground object from collection Main in the outliner into the other collection A
result (ground in A):
move ground object into other collection B
result (ground in B (same as in A)):
move ground back to Main, should looks same as Main above

**System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3080 Ti/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 552.44 **Blender Version** Broken: version: 4.2.3 LTS, branch: blender-v4.2-release, commit date: 2024-10-14 15:20, hash: `0e22e4fcea03` Broken: version: 4.3.0 Beta, branch: blender-v4.3-release, commit date: 2024-10-21 16:47, hash: `5fff95f5193e` Worked: (newest version of Blender that worked as expected) **Short description of error** The Z-Fighting in attached video is different if the affected object (in video it's the ground plane) gets moved into another collection. To be more precise it is worse if fighting objects A and B are in the same collection and better if they are in different collections. When in different collections the z-fighting doesn't change anymore if collections change, as long as they are not in the same collection. <video src="/attachments/29146433-3ab7-4f9a-a637-fcb667ac7879" title="2024-10-22 17-08-56.mkv" controls></video> This behaviour (at least in my opinion) is a discrepancy to the docs, which suggest only a organizational relationship exists. https://docs.blender.org/manual/en/latest/scene_layout/collections/collections.html: > Objects can be grouped together without any kind of transformation relationship (unlike parenting). Collections are used to just logically organize your scene, or to facilitate one-step appending or linking between files or across scenes. I don't know why this difference of collection relationship happens, but it's kind of annyoing. At first i thought it's the viewport rerendering, but then the visual appearance of the z-fighting would be different with each move of the object into a different collection, however the result is the same no matter if in collection A or B as long as not in Main. **Exact steps for others to reproduce the error** - Open attached file `z-fighting-bug.blend` - it should be in viewport shading material preview result (ground in Main): ![grafik](/attachments/f2b01cef-79cc-49cf-8b16-d4795d098963) - move ground object from collection Main in the outliner into the other collection A result (ground in A): ![grafik](/attachments/ec6f665e-f466-46cf-a085-5af8748c9f4e) - move ground object into other collection B result (ground in B (same as in A)): ![grafik](/attachments/979bb903-a9d8-48bd-a73e-361dde9a2f32) - move ground back to Main, should looks same as Main above

z-fighting-bug.blend

1.4 MiB

grafik.png

2.3 MiB

grafik.png

2.3 MiB

grafik.png

2.3 MiB

2024-10-22 17-08-56.mkv

4.0 MiB

Cedric Steiert added the

labels 2024-10-22 17:38:44 +02:00

Alaska commented

2024-10-23 10:00:16 +02:00

I can confirm the change in the appearance of z-fighting when shifting objects around collections. But z-fighting is still there.

I'm just guessing here, but I suspect shifting objects up and down collections change the order in which some objects are rendered, which could lead to a difference in how the z-fighting artifacts appear.

The Z-Fighting in attached video is different if the affected object (in video it's the ground plane) gets moved into another collection. To be more precise it is worse if fighting objects A and B are in the same collection and better if they are in different collections.

In my testing, the issue isn't related to "In different collections vs the same collections". It's instead related to the order in which the objects are arranged in collections.

For example if you create a collection below Main and shift the ground object from main to that one, the Z fighting doesn't change. Same goes if you shift Main to the top of the outliner, then shift the ground object to a lower collection.

Although there is a difference here, I do not believe this is a bug as we're in the realm of precision artifacts, where the outcome is a bit unpredictable. I will close this report.

I can confirm the change in the appearance of z-fighting when shifting objects around collections. But z-fighting is still there. I'm just guessing here, but I suspect shifting objects up and down collections change the order in which some objects are rendered, which could lead to a difference in how the z-fighting artifacts appear. > The Z-Fighting in attached video is different if the affected object (in video it's the ground plane) gets moved into another collection. To be more precise it is worse if fighting objects A and B are in the same collection and better if they are in different collections. In my testing, the issue isn't related to "In different collections vs the same collections". It's instead related to the order in which the objects are arranged in collections. For example if you create a collection below `Main` and shift the ground object from main to that one, the Z fighting doesn't change. Same goes if you shift `Main` to the top of the outliner, then shift the ground object to a lower collection. --- Although there is a difference here, I do not believe this is a bug as we're in the realm of precision artifacts, where the outcome is a bit unpredictable. I will close this report.

👍 1

Alaska closed this issue

2024-10-23 10:00:20 +02:00

Blender Bot added

and removed

labels 2024-10-23 10:00:22 +02:00

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