Mirror Global mirrors on local axis #82334

New Issue

Sean Robertson · 2020-11-02T20:12:59+01:00

Sean Robertson commented

2020-11-02 20:12:59 +01:00

System Information
Operating system: Darwin-19.6.0-x86_64-i386-64bit 64 Bits
Graphics card: Intel Iris Pro OpenGL Engine Intel Inc. 4.1 INTEL-14.7.8

Blender Version
Broken: version: 2.91.0 Alpha, branch: newboolean, commit date: 2020-08-05 19:52, hash: 843aead88e
Worked: none

Short description of error
Both the global and local options for the mirror tool appear to do the exact same thing, mirroring according to the local axis, with no way to correctly mirror per the global axes.

Exact steps for others to reproduce the error
Best thing I can do is show it - these are from Bforartists, but the behavior is identical regardless of Blender version or the scene used:

Exact steps:

Make an asymmetrical object and position to the left of center.
Set origin to world origin
Rotate 15°
Mirror X Global

Object will now be 15° above the X axis on the right, because the mirror is using the object's axis orientation, not the global orientation. Mirror Local does the same thing, so there is no difference between the two.

**System Information** Operating system: Darwin-19.6.0-x86_64-i386-64bit 64 Bits Graphics card: Intel Iris Pro OpenGL Engine Intel Inc. 4.1 INTEL-14.7.8 **Blender Version** Broken: version: 2.91.0 Alpha, branch: newboolean, commit date: 2020-08-05 19:52, hash: `843aead88e` Worked: none **Short description of error** Both the global and local options for the mirror tool appear to do the exact same thing, mirroring according to the local axis, with no way to correctly mirror per the global axes. **Exact steps for others to reproduce the error** Best thing I can do is show it - these are from Bforartists, but the behavior is identical regardless of Blender version or the scene used: ![Screen Shot 2020-11-02 at 11.11.46 AM.png](https://archive.blender.org/developer/F9170632/Screen_Shot_2020-11-02_at_11.11.46_AM.png) ![Screen Shot 2020-11-02 at 11.12.29 AM.png](https://archive.blender.org/developer/F9170638/Screen_Shot_2020-11-02_at_11.12.29_AM.png) ![Screen Shot 2020-11-02 at 11.12.39 AM.png](https://archive.blender.org/developer/F9170642/Screen_Shot_2020-11-02_at_11.12.39_AM.png) Exact steps: - Make an asymmetrical object and position to the left of center. - Set origin to world origin - Rotate 15° - Mirror X Global Object will now be 15° above the X axis on the right, because the mirror is using the object's axis orientation, not the global orientation. Mirror Local does the same thing, so there is no difference between the two.

Sean Robertson commented

2020-11-02 20:12:59 +01:00

Added subscriber: @seanr

Yevgeny Makarov commented

2020-11-03 08:08:52 +01:00

Added subscriber: @jenkm

Yevgeny Makarov commented

2020-11-03 08:08:52 +01:00

~~I can't reproduce this.~~
Please use the official build for reporting/screenshots.
And attach a simple .blend file.
And of course try loading the default settings.

~~I can't reproduce this.~~ Please use the official build for reporting/screenshots. And attach a **simple** .blend file. And of course try loading the default settings.

Germano Cavalcante commented

2020-11-03 19:41:45 +01:00

Added subscriber: @mano-wii

Germano Cavalcante commented

2020-11-03 19:41:46 +01:00

Changed status from 'Needs Triage' to: 'Needs User Info'

Germano Cavalcante commented

2020-11-03 19:41:46 +01:00

Are you using this operator in object mode?
Remembering that this is a tranform operator, and does not change the mesh of the object, but only scales in the direction indicated.

Objects in blender do not have a "shear" component.
This means that the objects are only scaled in the X, Y and Z directions.
These directions cannot represent the transformation you intend.
So blender uses an approximate transformation.

Are you using this operator in object mode? Remembering that this is a tranform operator, and does not change the mesh of the object, but only scales in the direction indicated. Objects in blender do not have a "shear" component. This means that the objects are only scaled in the X, Y and Z directions. These directions cannot represent the transformation you intend. So blender uses an approximate transformation.

Sean Robertson commented

2020-11-03 23:46:27 +01:00

Yes, this is in object mode. So it Blender can't mirror across the global X axis because of what you say (if that is indeed what you mean), then what is the purpose of "Mirror X Global"?

Sample file - as I said, this is a ridiculously simple problem, so the blend is probably useless anyway. ;)
mirror.blend

Yes, this is in object mode. So it Blender can't mirror across the global X axis because of what you say (if that is indeed what you mean), then what is the purpose of "Mirror X *Global*"? Sample file - as I said, this is a ridiculously simple problem, so the blend is probably useless anyway. ;) [mirror.blend](https://archive.blender.org/developer/F9186500/mirror.blend)

Robert Guetzkow commented

2020-11-04 10:21:04 +01:00

Added subscriber: @rjg

Robert Guetzkow commented

2020-11-04 10:21:04 +01:00

@seanr As @mano-wii said, Mirror > Global X just inverts the sign of the X-axis scale of the object, when used in object mode. It does not take the rotation into account. I can see that this is confusing, but this is how the operator works at least since 2.79 if not longer.

@seanr As @mano-wii said, *Mirror > Global X* just inverts the sign of the X-axis scale of the object, when used in object mode. It does not take the rotation into account. I can see that this is confusing, but this is how the operator works at least since 2.79 if not longer.

Robert Guetzkow commented

2020-11-04 10:35:37 +01:00

Changed status from 'Needs User Info' to: 'Archived'

Robert Guetzkow closed this issue

2020-11-04 10:35:37 +01:00

Robert Guetzkow self-assigned this 2020-11-04 10:35:37 +01:00

Robert Guetzkow commented

2020-11-04 10:35:37 +01:00

I'm closing this ticket as invalid, as to the best of my knowledge the operator is working as designed.

Changing the behavior or adding an operator that works as suggested, would be considered an improvement suggestion / feature request. Those are off-topic on the bug tracker. I do agree that the name is arguably confusing.

I'm closing this ticket as invalid, as to the best of my knowledge the operator is working as designed. Changing the behavior or adding an operator that works as suggested, would be considered an improvement suggestion / feature request. Those are off-topic on the bug tracker. I do agree that the name is arguably confusing.

Yevgeny Makarov commented

2020-11-04 10:41:23 +01:00

In 2.79, in Object Mode, in the Mirror menu was only Global's, (should be Local though).

https://developer.blender.org/rBf889050aea70c2ff3c36c8c8600dd2b02d5e9f91

I think in the Object Mode the Global's should be hidden, (there's still interactive mode and redo).

I can propose a patch if it's reasonable.

In 2.79, in Object Mode, in the Mirror menu was only Global's, (should be Local though). https://developer.blender.org/rBf889050aea70c2ff3c36c8c8600dd2b02d5e9f91 I think in the Object Mode the Global's should be hidden, (there's still interactive mode and redo). I can propose a patch if it's reasonable.

Sean Robertson commented

2020-11-04 17:39:35 +01:00

So this may be "as designed", but how it's designed is illogical - mirroring should be moving all vertices to the opposite side of the axis chosen (just invert the distance of each vertex from that axis). If it isn't doing that, it's not really mirroring. ;) Further, there clearly aren't two different operations given that it isn't really mirroring in that sense, so why two different buttons?

So this may be "as designed", but how it's designed is illogical - mirroring should be moving all vertices to the opposite side of the axis chosen (just invert the distance of each vertex from that axis). If it isn't doing that, it's not really mirroring. ;) Further, there clearly _aren't_ two different operations given that it isn't really mirroring in that sense, so why two different buttons?

Robert Guetzkow commented

2020-11-05 09:39:42 +01:00

@seanr I completely agree that how it's currently implemented and how it's named doesn't match. @jenkm I think this would be a good idea, but even better if the operator does what its name says (in object mode). Just for clarification, I had to close the ticket because we have fairly strict rules when it comes to what is considered a bug and I will have to follow the guidance of our core developers.

@mano-wii If you think this should be reopened and marked as "ToDo" or confirmed as known issue, let me know.

@seanr I completely agree that how it's currently implemented and how it's named doesn't match. @jenkm I think this would be a good idea, but even better if the operator does what its name says (in object mode). Just for clarification, I had to close the ticket because we have fairly strict rules when it comes to [what is considered a bug ](https://wiki.blender.org/wiki/Reference/Not_a_bug) and I will have to follow the guidance of our core developers. @mano-wii If you think this should be reopened and marked as "ToDo" or confirmed as known issue, let me know.

Sean Robertson commented

2020-11-27 15:44:27 +01:00

@rjg if it's not appropriate here per those rules, then where is it appropriate? It may not technically be a bug from the developers' perspective, but it's absolutely horrible behavior that from the perspective of the user is a bug, even if the bug is the design itself. There's a lot of UX stuff like this in Blender, frankly, and the response here seems to be to sweep them under a rug. How do we get these kinds of things actually fixed (and I use fixed deliberately, as the current behavior is broken to any rational user)?

@rjg if it's not appropriate here per those rules, then where is it appropriate? It may not technically be a bug from the developers' perspective, but it's absolutely horrible behavior that from the perspective of the user *is* a bug, even if the bug is the design itself. There's a lot of UX stuff like this in Blender, frankly, and the response here seems to be to sweep them under a rug. How do we get these kinds of things actually fixed (and I use *fixed* deliberately, as the current behavior is broken to any rational user)?

Robert Guetzkow commented

2020-11-27 15:50:35 +01:00

@seanr I see @mano-wii was fast than me. There's a patch in development.

I personally agree that the current implementation is not ideal, at least with the given name. The ticket was originally closed because the very same issue was previously reported in another ticket and closed by a core dev. Additionally, we have very strict rules about improvements suggestions and feature requests, which should usually be posted on right-click select . I admit that I might have been a bit quick in closing this though. I know the "works as design" reply can be very annoying, but we have to draw the line between "improvements suggestion (off-topic)" and "UX so terrible it is considered a bug (on-topic)" somewhere.

@seanr I see @mano-wii was fast than me. There's a patch in development. I personally agree that the current implementation is not ideal, at least with the given name. The ticket was originally closed because the very same issue was previously reported in another ticket and closed by a core dev. Additionally, we have very strict rules about improvements suggestions and feature requests, which should usually be posted on [right-click select ](https://blender.community/c/rightclickselect/). I admit that I might have been a bit quick in closing this though. I know the "works as design" reply can be very annoying, but we have to draw the line between "improvements suggestion (off-topic)" and "UX so terrible it is considered a bug (on-topic)" somewhere.

blender-admin commented

2020-12-02 13:09:26 +01:00

This issue was referenced by ec39d8de4a

This issue was referenced by ec39d8de4adf46161d81fb525a73278fe08a8704

Germano Cavalcante commented

2020-12-02 13:29:43 +01:00

Changed status from 'Archived' to: 'Resolved'

Robert Guetzkow commented

2020-12-02 13:41:17 +01:00

@seanr The patch has been committed to the master branch thanks to @weasel. Tomorrow's daily build of 2.92 should include this feature, if you want to test it.

Robert Guetzkow commented

2020-12-02 13:49:10 +01:00

Added subscriber: @HDMaster84

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Reference: blender/blender#82334

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Mirror Global mirrors on local axis #82334