'Mirror Vertex Group' operator doesn't apply to selected Vertex Group #92510

New Issue

Sam Walker · 2021-10-26T20:54:19+02:00

Sam Walker commented

2021-10-26 20:54:19 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 3090/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 471.68

Blender Version
Broken: version: 2.93.5, branch: master, commit date: 2021-10-05 12:04, hash: a791bdabd0
Worked: N/A (but following steps described in the 2.93 online manual), does not work at all in 2.79b.

Short description of error
Following the steps detailed in the "Mirror to Opposite Bone" tip in the online manual here , applying the 'Mirror Vertex Group' operator does not mirror the currently selected vertex group in the 'Vertex Groups' Object Data Properties tab. Assuming this is a bug as I can't find a way to reliably achieve the intended behaviour.

Exact steps for others to reproduce the error

Open attached .blend
Select "Upper.l" in the 'Vertex Groups' list, in the 'Object Data Properties' panel.
Twirl down the 'Vertex Group Specials' menu to the right and press 'Copy Vertex Group'.
Rename the copy to "Upper.r" (the name of the corresponding bone on the right-hand side).
Make sure the new "Upper.r" group is selected, twirl down the 'Vertex Group Specials' menu again and select 'Mirror Vertex Groups'.
The selected "Upper.r" vertex group remains unchanged, however the original "Upper.l" group is mirrored. It's expected that the "Upper.r" group should be the one that gets mirrored.

Mirror Vertex Groups Bug_v1.blend

Problem is that it defaults to having the Flip Group Names option on.
Hit {key F9} (to bring up the Adjust last Operation panel), uncheck Flip Group Names.

This will then works somewhat expected, but it is very hidden (since there is not even a Adjust last Operation panel by default in the Properties Editor.

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 3090/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 471.68 **Blender Version** Broken: version: 2.93.5, branch: master, commit date: 2021-10-05 12:04, hash: `a791bdabd0` Worked: N/A (but following steps described in the 2.93 online manual), does not work at all in 2.79b. **Short description of error** Following the steps detailed in the "Mirror to Opposite Bone" tip in the online manual [here ](https://docs.blender.org/manual/en/2.93/sculpt_paint/weight_paint/editing.html#bpy-ops-object-vertex-group-mirror), applying the 'Mirror Vertex Group' operator does not mirror the currently selected vertex group in the 'Vertex Groups' Object Data Properties tab. Assuming this is a bug as I can't find a way to reliably achieve the intended behaviour. **Exact steps for others to reproduce the error** - Open attached .blend - Select "Upper.l" in the 'Vertex Groups' list, in the 'Object Data Properties' panel. - Twirl down the 'Vertex Group Specials' menu to the right and press 'Copy Vertex Group'. - Rename the copy to "Upper.r" (the name of the corresponding bone on the right-hand side). - Make sure the new "Upper.r" group is selected, twirl down the 'Vertex Group Specials' menu again and select 'Mirror Vertex Groups'. - The selected "Upper.r" vertex group remains unchanged, however the original "Upper.l" group is mirrored. It's expected that the "Upper.r" group should be the one that gets mirrored. [Mirror Vertex Groups Bug_v1.blend](https://archive.blender.org/developer/F11527141/Mirror_Vertex_Groups_Bug_v1.blend) Problem is that it defaults to having the `Flip Group Names` option on. Hit {key F9} (to bring up the `Adjust last Operation` panel), uncheck `Flip Group Names`. This will then works somewhat expected, but it is very hidden (since there is not even a `Adjust last Operation` panel by default in the Properties Editor.

Sam Walker commented

2021-10-26 20:54:19 +02:00

Added subscriber: @Hexbob6

Jan-Willem van Dronkelaar commented

2021-10-26 23:50:45 +02:00

Added subscriber: @jwvdronkelaar

Jan-Willem van Dronkelaar commented

2021-10-26 23:50:45 +02:00

This comment was removed by @jwvdronkelaar

*This comment was removed by @jwvdronkelaar*

Richard Antalik commented

2021-10-27 06:16:53 +02:00

Added subscriber: @iss

Richard Antalik commented

2021-10-27 06:16:53 +02:00

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

Richard Antalik commented

2021-10-27 06:16:53 +02:00

Seems to happen in older versions too, checked 2.91. When you run operator again it actually mirrors both left and right, so you would get intended result, but I don't think this is intentional. I wasn't able to see from code though.

Sam Walker commented

2021-10-27 12:15:30 +02:00

I'm sure I've seen this operator work correctly in the past but have just downloaded and tested in the last stable build of 2.79b and it seems to not work at all (ie. nothing gets flipped, regardless of the selected group), despite giving an incorrect info notification saying '525 vertices mirrored' - so in that respect, despite not working as expected in 2.9x, it's an improvement! 😄 Has it really been broken for so long though, I'm sure I've run into scenarios where I've needed to mirror v.groups before and done so without issue but it seems like... maybe not?

Here's a 2.79b-compatible file in case it's needed for testing:
279b_Mirror Vertex Groups Bug_v1.blend

I'm sure I've seen this operator work correctly in the past but have just downloaded and tested in the last stable build of 2.79b and it seems to not work at all (ie. nothing gets flipped, regardless of the selected group), despite giving an incorrect info notification saying '525 vertices mirrored' - so in that respect, despite not working as expected in 2.9x, it's an improvement! 😄 Has it really been broken for so long though, I'm sure I've run into scenarios where I've needed to mirror v.groups before and done so without issue but it seems like... maybe not? Here's a 2.79b-compatible file in case it's needed for testing: [279b_Mirror Vertex Groups Bug_v1.blend](https://archive.blender.org/developer/F11541862/279b_Mirror_Vertex_Groups_Bug_v1.blend)

Philipp Oeser commented

2021-10-27 13:27:50 +02:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2021-10-27 13:27:50 +02:00

I think it defaults to having the Flip Group Names option on.
Hit {key F9} (to bring up the Adjust last Operation panel), uncheck Flip Group Names.

So actually, this does not look like a bug to me.

Can anyone confirm?

I think it defaults to having the `Flip Group Names` option on. Hit {key F9} (to bring up the `Adjust last Operation` panel), uncheck `Flip Group Names`. So actually, this does not look like a bug to me. Can anyone confirm?

Richard Antalik commented

2021-10-28 09:41:30 +02:00

In #92510#1242427, @lichtwerk wrote:
I think it defaults to having the Flip Group Names option on.
Hit {key F9} (to bring up the Adjust last Operation panel), uncheck Flip Group Names.

So actually, this does not look like a bug to me.

Can anyone confirm?

Can confirm, I did not check operator properties. So this seems to work as designed, though not really sure if it works as intended.

> In #92510#1242427, @lichtwerk wrote: > I think it defaults to having the `Flip Group Names` option on. > Hit {key F9} (to bring up the `Adjust last Operation` panel), uncheck `Flip Group Names`. > > So actually, this does not look like a bug to me. > > Can anyone confirm? Can confirm, I did not check operator properties. So this seems to work as designed, though not really sure if it works as intended.

Sam Walker commented

2021-10-29 20:31:36 +02:00

Interesting, yes I can confirm as well that subsequently disabling the 'Flip Group Names' checkbox in the operator properties causes the mirroring to occur correctly. As well, using the operator with 'Flip Group Names' enabled before renaming the copy to "Upper.r" causes the mirroring to work as expected.

I will say however that from a UX standpoint I'd agree with you, @iss, in that although it works as designed possibly doesn't work as the user intends. Perhaps when calling the 'Mirror Vertex Group' operator from the 'Vertex Group Specials' drop down, if possible it would be more intuitive to disable the 'Flip Group Names' default? Even as an advanced user, the lack of a last operation panel when you run it from that menu (without pressing {key F9}) - alongside an operator name that suggests a different default function - can evidently make it tricky to figure out exactly why it's working the way that it is?

This is also true for the 'Flip Group Names' parameter. From the name it seems like you should be able to select a vertex group, run the operator with said parameter enabled and as a result it will rename the "Upper.l" vertex group to "Upper.r", for example, yet this also doesn't seem to be the case?

Interesting, yes I can confirm as well that subsequently disabling the 'Flip Group Names' checkbox in the operator properties causes the mirroring to occur correctly. As well, using the operator with 'Flip Group Names' enabled **before** renaming the copy to "Upper.r" causes the mirroring to work as expected. I will say however that from a UX standpoint I'd agree with you, @iss, in that although it works as designed possibly doesn't work as the user intends. Perhaps when calling the 'Mirror Vertex Group' operator from the 'Vertex Group Specials' drop down, if possible it would be more intuitive to disable the 'Flip Group Names' default? Even as an advanced user, the lack of a last operation panel when you run it from that menu (without pressing {key F9}) - alongside an operator name that suggests a different default function - can evidently make it tricky to figure out exactly why it's working the way that it is? This is also true for the 'Flip Group Names' parameter. From the name it seems like you should be able to select a vertex group, run the operator with said parameter enabled and as a result it will rename the "Upper.l" vertex group to "Upper.r", for example, yet this also doesn't seem to be the case?

Philipp Oeser commented

2021-11-01 08:33:37 +01:00

This looks like it needs some design work first.

Philipp Oeser removed the

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'Mirror Vertex Group' operator doesn't apply to selected Vertex Group #92510