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Maniphest T63434

Undoing the removal of a vertex group in edit mode changes other vertex groups and doesnt bring the removed vertex group back
Confirmed, NormalPublicKNOWN ISSUE
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Description

System Information
Operating system: Linux-5.4.13-201.fc31.x86_64-x86_64-with-fedora-31-Thirty_One 64 Bits
Graphics card: GeForce GTX 970M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 440.44

Blender Version
Broken: version: 2.83 (sub 2), branch: master (modified), commit date: 2020-02-06 03:03, hash: rB02226ef653e1
Worked: (optional)

Short description of error
Undoing a vertex group changes the rest. The video should show the issue. There's 3 vertex groups, A = A, B = B and C = C. If you delete A, B = B and C = C. If you delete A and then undo it, B = A and C = B.

https://youtu.be/Ty9U5rj_6Sw

T63434.blend545 KBDownload

  • Open File
  • you should be in editmode
  • remove the zero_weight vertex group
  • Undo Ctrl+Z
  • zero_weight vertex group is not back
  • half_weight vertex group now has zero weights
  • full_weight vertex group now has half weights

Related Objects

Event Timeline

Zachary (AFWS) created this task.Apr 9 2019, 8:13 PM
Sebastian Parborg (zeddb) lowered the priority of this task from 90 to 30.Apr 9 2019, 10:37 PM
Sebastian Parborg (zeddb) added a subscriber: Sebastian Parborg (zeddb).

I can't reproduce this on my end.

Is there anything I'm doing wrong?

Zachary (AFWS) added a comment.Apr 10 2019, 2:25 PM

@Sebastian Parborg (zeddb)

Try doing it in edit mode. I see you're doing this in weight paint mode. I can get the same results as you if I'm in weight paint. Looks like this is a undo issue in edit mode.

Zachary (AFWS) renamed this task from Undoing a vertex group changes the rest to Undoing a vertex group in edit mode.Apr 10 2019, 2:32 PM
Sebastian Parborg (zeddb) assigned this task to Campbell Barton (campbellbarton).Apr 10 2019, 3:35 PM
Sebastian Parborg (zeddb) raised the priority of this task from 30 to 50.

Right, if you are in edit mode it breaks.

Dalai Felinto (dfelinto) removed Campbell Barton (campbellbarton) as the assignee of this task.Dec 23 2019, 4:34 PM
Dalai Felinto (dfelinto) added a project: Tracker Curfew.
Dalai Felinto (dfelinto) added a subscriber: Campbell Barton (campbellbarton).
Richard Antalik (ISS) changed the task status from Confirmed to Needs Information from User.Jan 30 2020, 12:56 AM
Richard Antalik (ISS) added a subscriber: Richard Antalik (ISS).

I have re-triaged this report and can not reproduce it (even in edit mode).
Can you please check if this is still an issue in latest build?
https://builder.blender.org/download/

Philipp Oeser (lichtwerk) changed the task status from Needs Information from User to Confirmed.Feb 6 2020, 10:46 AM
Philipp Oeser (lichtwerk) changed the subtype of this task from "Report" to "Bug".
Philipp Oeser (lichtwerk) edited projects, added Modeling; removed Tracker Curfew.
Philipp Oeser (lichtwerk) added a subscriber: Philipp Oeser (lichtwerk).

Can confirm, still an issue, will update report with example file and better repro steps

Philipp Oeser (lichtwerk) renamed this task from Undoing a vertex group in edit mode to Undoing the removal of a vertex group in edit mode changes other vertex groups and doesnt bring the removed vertex group back.Feb 6 2020, 10:51 AM
Philipp Oeser (lichtwerk) updated the task description. (Show Details)
Campbell Barton (campbellbarton) moved this task from Backlog to Bugs on the Modeling board.Jun 17 2020, 5:17 AM
Bastien Montagne (mont29) changed the subtype of this task from "Bug" to "Known Issue".Sep 24 2020, 11:49 AM
Bastien Montagne (mont29) added a project: Pipeline, Assets & I/O.
Bastien Montagne (mont29) added a subscriber: Bastien Montagne (mont29).

This is a known issue actually, caused by design flaw in vgroups (they are stored partly in mesh, partly in object). Edit mesh undo steps cannot store undo data for anything else than the mesh, so to support this we'd need to either store a global memfile undo step (which is not possible currently in Edit mode afaik).

Workaround for now could be to forbid editing vgroup list in Edit mode, don't see anything we can do otherwise without some rather severe rework of part of undo code, which goes beyond a bugfix.

Bastien Montagne (mont29) moved this task from Bugs to Known Issues on the Modeling board.Sep 24 2020, 11:49 AM
Bastien Montagne (mont29) moved this task from Backlog to Known Issues on the Pipeline, Assets & I/O board.
Germano Cavalcante (mano-wii) mentioned this in T56163: Improve MemFile Undo (for general use).Nov 24 2020, 1:36 PM
Bastien Montagne (mont29) edited projects, added Core; removed Pipeline, Assets & I/O.Feb 16 2021, 6:20 PM
Bastien Montagne (mont29) moved this task from Backlog to Known Issues on the Core board.Feb 16 2021, 6:32 PM
Bastien Montagne (mont29) added a project: Restricted Project.Jun 24 2021, 12:38 PM
Bastien Montagne (mont29) moved this task from Restricted Project Column to Restricted Project Column on the Restricted Project board.Jan 27 2022, 5:58 PM
Henrik Dick (weasel) added a subscriber: Henrik Dick (weasel).Mar 3 2022, 1:22 PM

@Bastien Montagne (mont29) Even if undo of vertex group can be considered a known issue, the silent corruption of all the other vertex groups should be considered a bug and should get fixed (maybe by disabling the undo behavior here completely?).

Bastien Montagne (mont29) added a comment.Mar 3 2022, 2:29 PM

@Henrik Dick (weasel) If you do have time to work on this, please feel free to assign it to yourself and then move this to bug. By definition 'bugs' are issues that are intended to be fixed within a reasonable time, otherwise (especially when current design is at core of the issue), they are 'known issues'.