YEEK! this should be recoded! Shape key loss! #84180

New Issue

Thomas Larsson · 2020-12-27T18:23:41+01:00

Thomas Larsson commented

2020-12-27 18:23:41 +01:00

System Information
Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: Quadro K2200/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 385.54

Blender Version
Broken: version: 2.91.0, branch: master, commit date: 2020-11-25 08:34, hash: 0f45cab862
Worked: (newest version of Blender that worked as expected)

Short description of error
I have a HD mesh with a shapekey. The HD mesh was generated in DAZ Studio with 3 subd levels, Catmark subdivision. Then I add a multires modifier and rebuild subdivisions. Three levels are rebuilt but the shapekey is lost, with the following error message in the terminal:

ERROR (bke.mesh_convert): C:\b\buildbot-worker-windows\windows_291\blender.git\source\blender\blenkernel\intern\mesh_convert.c:1656 BKE_mesh_nomain_to_mesh: YEEK! this should be recoded! Shape key loss!: ID 'MEgeometry_HD'
Info: 3 new levels rebuilt
yeek.blend

**System Information** Operating system: Windows-7-6.1.7601-SP1 64 Bits Graphics card: Quadro K2200/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 385.54 **Blender Version** Broken: version: 2.91.0, branch: master, commit date: 2020-11-25 08:34, hash: `0f45cab862` Worked: (newest version of Blender that worked as expected) **Short description of error** I have a HD mesh with a shapekey. The HD mesh was generated in DAZ Studio with 3 subd levels, Catmark subdivision. Then I add a multires modifier and rebuild subdivisions. Three levels are rebuilt but the shapekey is lost, with the following error message in the terminal: ERROR (bke.mesh_convert): C:\b\buildbot-worker-windows\windows_291\blender.git\source\blender\blenkernel\intern\mesh_convert.c:1656 BKE_mesh_nomain_to_mesh: YEEK! this should be recoded! Shape key loss!: ID 'MEgeometry_HD' Info: 3 new levels rebuilt [yeek.blend](https://archive.blender.org/developer/F9532195/yeek.blend)

Thomas Larsson commented

2020-12-27 18:23:41 +01:00

Added subscriber: @thomasl-3

Philipp Oeser commented

2021-01-06 12:38:35 +01:00

Added subscribers: @dr.sybren, @lichtwerk

Philipp Oeser commented

2021-01-06 12:38:35 +01:00

Changed status from 'Needs Triage' to: 'Confirmed'

Philipp Oeser commented

2021-01-06 12:38:35 +01:00

Can confirm it happens.

This sounds like a TODO though, not sure how to classify.
@dr.sybren: since you added this in c0dd355926, mind sharing your thoughts?

Can confirm it happens. This sounds like a TODO though, not sure how to classify. @dr.sybren: since you added this in c0dd355926, mind sharing your thoughts?

Sybren A. Stüvel commented

2021-01-08 14:41:40 +01:00

Added subscribers: @Sergey, @JosephEagar

Sybren A. Stüvel commented

2021-01-08 14:41:40 +01:00

The message wasn't mine, but was copied from DerivedMesh.c. It originated in a37bcf93ef by @JosephEagar, 10 years ago.
I don't know whether maintaining shapekeys is actually supported when working with multires this way. @Sergey probably knows more about this.

The message wasn't mine, but was copied from `DerivedMesh.c`. It originated in a37bcf93ef by @JosephEagar, 10 years ago. I don't know whether maintaining shapekeys is actually supported when working with multires this way. @Sergey probably knows more about this.

Sergey Sharybin commented

2021-01-12 16:10:11 +01:00

Think rebuild subdivisions should handle shapekeys in a similar manner how edit mode is doing it. It will be lossy, but probably still better than fully loosing the keys.

Sybren A. Stüvel commented

2021-01-12 16:16:44 +01:00

Removed subscriber: @dr.sybren

Sybren A. Stüvel commented

2021-01-12 16:16:44 +01:00

In that case I'll step down from this task, I'm not involved in multires editing.

Sergey Sharybin commented

2021-01-12 16:21:34 +01:00

Added subscriber: @PabloDobarro

Sergey Sharybin commented

2021-01-12 16:21:34 +01:00

Is not really multires, but the multires-rebuild, which sounds related, but is a special piece of code.

@PabloDobarro think it's something for you?

Is not really multires, but the multires-rebuild, which sounds related, but is a special piece of code. @PabloDobarro think it's something for you?

Pablo Dobarro commented

2021-01-13 03:13:10 +01:00

I can take a look if there is something wrong in unsubdivide that may be causing the warning, but I don't think I'm going to be able to make it work.
As a general comment regarding all Multires + shape keys reports (there are quite a lot of them), the issue is that is not clear what those operation should do if they were working as expected.
If we take this report as an example, when unsubdivide runs on a mesh with shape keys, it will dissolve vertices in the original mesh and then reshape the result. After that operation, what information is supposed to be stored in the shape keys in order for it to be useful?
I think that a unsubdivide operation with shape keys support should output the level 0 base mesh after the reshape and a CD_MDISP datalayer per shape key, so they can be stored in something like tangent space sculpt layers. This is not supported at all, so any workaround for these kind of issues will be confusing in one way or another.

I can take a look if there is something wrong in unsubdivide that may be causing the warning, but I don't think I'm going to be able to make it work. As a general comment regarding all Multires + shape keys reports (there are quite a lot of them), the issue is that is not clear what those operation should do if they were working as expected. If we take this report as an example, when unsubdivide runs on a mesh with shape keys, it will dissolve vertices in the original mesh and then reshape the result. After that operation, what information is supposed to be stored in the shape keys in order for it to be useful? I think that a unsubdivide operation with shape keys support should output the level 0 base mesh after the reshape and a CD_MDISP datalayer per shape key, so they can be stored in something like tangent space sculpt layers. This is not supported at all, so any workaround for these kind of issues will be confusing in one way or another.

Sergey Sharybin commented

2021-01-13 09:44:21 +01:00

@PabloDobarro think of it as if it was a user who was dissolving vertices in edit mode and then used Reshape button.

Julien Kaspar commented

2022-05-12 14:05:34 +02:00

Added subscriber: @JulienKaspar

Julien Kaspar commented

2022-05-12 14:05:34 +02:00

I'll tag this as a known issue. This probably won't be worked on for a while until bigger improvements for multires get worked on.

Philipp Oeser removed the

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YEEK! this should be recoded! Shape key loss! #84180