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Shapekey Multires issue when toggling mirror options via shortcut after undo
Confirmed, NormalPublicBUG


System Information
Operating system: Linux-5.3.0-55-generic-x86_64-with-debian-buster-sid 64 Bits
Graphics card: Quadro GP100/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 440.59

Blender Version
Broken: version: 2.90.0 Alpha, branch: master, commit date: 2020-06-10 08:04, hash: rBfc8a7a44b200
Worked: 2.83.0

Short description of error
In my personal keymap I have set the toggle for x-mirror in sculpt mode to Ctrl + X.
I notices small performance issues where Blender would take longer when toggling it via the shortcut or using undo up to the point where x-mirror was toggled.
This might be unrelated to this bug though:
When you sculpt on an object with a shapekey and the multires modifier and then use undo, if you directly afterwards toggle one of the mirror options via a shortcut, it will immediately apply the deformations of that shapekey onto the multires subdivisions.

This will not happen when pressing the buttons in the header and only if using the shortcut.
It will only happen once unless sculpt mode is exited and entered again.

Exact steps for others to reproduce the error

  • Assign a shortcut to the x/y/ or z mirror option in sculpt mode
  • Add an object like a sphere or subdivide the default cube
  • Add a base and a shapekey in the shapekey panel and set it to an influence of 1
  • Add a multires modifier and subdivide it 3 times
  • Model or sculpt some deformations for the shapekey on the base resolution
  • Enter sculpt mode on detail level 3 on the multires
  • Sculpt some strokes
  • Undo
  • Press the shortcut for the mirror option


  1. Open attached file
  2. Sculpt (Press and drag any part of the object)
  3. Undo (Ctrl Z)
  4. Exit and enter to sculpt mode (Tab Tab for example)

Event Timeline

Julien Kaspar (JulienKaspar) renamed this task from Shapekey Multires issue when toggling mirror options via shortcut on first undo step to Shapekey Multires issue when toggling mirror options via shortcut after undo.Wed, Jun 10, 7:06 PM
Julien Kaspar (JulienKaspar) created this task.

I'm confused. I don't know where to expect to see the bug.
I'm testing this file but shortcut only enables or disables the x-mirror option.
Even leaving and returning to sculpt mode I don't see the bug.
Has any step been missing in the description?

@Germano Cavalcante (mano-wii) I just tested it on another computer as well and I can reproduce the bug with the outlines steps.
In your file you didn't make any changes to the shapekey. You need to model or sculpt changes on the base resolution (level 0) since the multires subdivisions are not changing the base and therefore don't affect the shapekeys.

Ok apparently instead of using the custom shortcut I mentioned, this can also be more easily replicated by just using undo, exiting sculpt mode and entering sculpt mode again.
The same effect is then suddenly visible.

Germano Cavalcante (mano-wii) changed the task status from Needs Triage to Confirmed.Tue, Jun 16, 10:44 PM
Germano Cavalcante (mano-wii) updated the task description. (Show Details)
Germano Cavalcante (mano-wii) changed the subtype of this task from "Report" to "Bug".