Library overrides get reset when the linked file changes #110742

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System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: Quadro RTX 3000 with Max-Q Design/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 536.67

Blender Version
Broken: version: 3.6.1 Release Candidate, branch: blender-v3.6-release, commit date: 2023-07-16 02:43, hash: edc1a09966a7
Worked: (newest version of Blender that worked as expected)

Short description of error
[Please fill out a short description of the error here]

Exact steps for others to reproduce the error

Link a collection from a different file
Override everything (selection & content & data etc down to the materials, so that materials have an O in front of them)
Replace a few materials on some objects with new materials
Go into the originally linked different file and make some changes to a mesh (and perhaps move some meshes to a different collection that's not linked)
Open the files with the link in it

Result:

All material changes have now been reset

Expected:

The overriden materials should of course stay the same!

**System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: Quadro RTX 3000 with Max-Q Design/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 536.67 **Blender Version** Broken: version: 3.6.1 Release Candidate, branch: blender-v3.6-release, commit date: 2023-07-16 02:43, hash: `edc1a09966a7` Worked: (newest version of Blender that worked as expected) **Short description of error** [Please fill out a short description of the error here] **Exact steps for others to reproduce the error** 1. Link a collection from a different file 2. Override everything (selection & content & data etc down to the materials, so that materials have an O in front of them) 3. Replace a few materials on some objects with new materials 4. Go into the originally linked different file and make some changes to a mesh (and perhaps move some meshes to a different collection that's not linked) 5. Open the files with the link in it Result: All material changes have now been reset Expected: The overriden materials should of course stay the same!

Hi, thanks for the report.

Replace a few materials on some objects with new materials

I'm not sure how you could replace material on overridden object. Can you expand on that?
Is it possible actually on overridden data-blocks? Like add or remove the material.

Attaching the reference file which I'm using.

Hi, thanks for the report. > Replace a few materials on some objects with new materials I'm not sure how you could replace material on overridden object. Can you expand on that? Is it possible actually on overridden data-blocks? Like add or remove the material. Attaching the reference file which I'm using.

link.blend

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override.blend

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Please see the attached video and example files.

Desktop.zip

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output.webm

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Thanks, unable to confirm as demonstrated in video, will check again later.
Looks like override resyncing happened when linked collection is changed in source file.

Thanks, unable to confirm as demonstrated in video, will check again later. Looks like override resyncing happened when linked collection is changed in source file.

There's a lot of weird things happening when working with material overrides... I don't even know what to say about this one:

output4.webm

2.8 MiB

Great, after thinking that what could be seen above in the video could be "fixed" manually, by deleting the extra objects which appear, but after saving and re-loading the hierarchy of many unrelated objects in the file is messed up (similar to this but not as severe). I'll say this again, linked library overrides is not ready for production! ☹

Great, after thinking that what could be seen above in the video could be "fixed" manually, by deleting the extra objects which appear, but after saving and re-loading the hierarchy of many unrelated objects in the file is messed up (similar to [this ](https://projects.blender.org/blender/blender/issues/110744)but not as severe). I'll say this again, linked library overrides is not ready for production! ☹

#110742 (comment) I do think this one should keep overridden since the hierarchy of the object/material isn't changed.

In 3.6.1, the changed material slot isn't kept.
However, in 4.0, I am able to keep the modified material after changing material in the source file, so unable to confirm this:

3.6.1	4.0

Not sure about the second video about those BREP objects tho...

@RobertS Could you try using 4.0 and see if it works as expected? Thanks!

https://projects.blender.org/blender/blender/issues/110742#issuecomment-991842 I do think this one should keep overridden since the hierarchy of the object/material isn't changed. - In 3.6.1, the changed material slot isn't kept. - However, in 4.0, I am able to keep the modified material after changing material in the source file, so unable to confirm this: | 3.6.1 | 4.0 | |---|---| | ![图片](/attachments/1e3bd0d1-ca24-4829-9747-e2c1f06f91bc) | ![图片](/attachments/a0ba870a-55bc-4023-a878-70802e14bf14) | Not sure about the second video about those `BREP` objects tho... @RobertS Could you try using 4.0 and see if it works as expected? Thanks!

图片.png

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图片.png

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Yes, testing the example file does seem as if it's fixed in 4.0 alpha.

Yes, testing the example file does seem as if it's fixed in 4.0 alpha.

Thanks. In that case we need to identify the resolving commit for backporting. (I'll check)
Perhaps same commits has fixed this?: #109993 (comment)

> Yes, testing the example file does seem as if it's fixed in 4.0 alpha. Thanks. In that case we need to identify the resolving commit for backporting. (I'll check) Perhaps same commits has fixed this?: https://projects.blender.org/blender/blender/issues/109993#issuecomment-977722

Seems to be #109993 . Can't find other relevant commits that does the job.

Just a FYI, I still see it in other places in 4.0 and I get a crash on top of it.

Unfortunately, it's in a large and sensitive project at work, so I can't share the file and attempts to remove everything but the affected objects have failed to reproduce it.

In this new variant, it seems to be restricted to objects with more than one material, and what happens is that the overriden material in the first slot actually gets applied to the second slot as well (although, for the green object in the screenshot, it's actually a third slot material that got put in the first slot instead of my override). And as mentioned in that other issue, if I delete everything except those two objects from my files, I can no longer replicate the problem.

Just a FYI, I still see it in other places in 4.0 and [I get a crash on top of it](https://projects.blender.org/blender/blender/issues/110749#issuecomment-995434). Unfortunately, it's in a large and sensitive project at work, so I can't share the file and attempts to remove everything but the affected objects have failed to reproduce it. In this new variant, it seems to be restricted to objects with more than one material, and what happens is that the overriden material in the first slot actually gets applied to the second slot as well (although, for the green object in the screenshot, it's actually a third slot material that got put in the first slot instead of my override). And as mentioned in that other issue, if I delete everything except those two objects from my files, I can no longer replicate the problem.

Skärmbild 2023-08-09 143610.jpg

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Skärmbild 2023-08-09 143302.jpg

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