UV Editor face select mode fails to select ngons reliably #104374

New Issue

Ludvik Koutny · 2023-02-06T12:24:00+01:00

Ludvik Koutny commented

2023-02-06 12:24:00 +01:00

System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 526.98

Blender Version
Broken: version: 3.4.1, branch: blender-v3.4-release, commit date: 2022-12-19 17:00, hash: 55485cb379
Worked: never? (2.83 fails too)

Short description of error
UV Editor face selection mode fails to select ngons reliably, because it uses face dot based selection, which can not be turned off. I was told to report scenarios where face dot based selection fails to work as bugs, so I am doing so here.

Exact steps for others to reproduce the error

Open the attached file
Select the mesh object, enter the edit mode, and in the UV editor, switch selection mode to face
Attempt to select some of the larger ngon UV face
Result: The selection of larger ngon UV faces fails in many cases
Expected The UV faces under the mouse cursor are selected when clicked on

UVSelectBug.blend
2023-02-06 12-20-58.mp4

**System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 526.98 **Blender Version** Broken: version: 3.4.1, branch: blender-v3.4-release, commit date: 2022-12-19 17:00, hash: `55485cb379` Worked: never? (2.83 fails too) **Short description of error** UV Editor face selection mode fails to select ngons reliably, because it uses face dot based selection, which can not be turned off. I was told to report scenarios where face dot based selection fails to work as bugs, so I am doing so here. **Exact steps for others to reproduce the error** 1. Open the attached file 2. Select the mesh object, enter the edit mode, and in the UV editor, switch selection mode to face 3. Attempt to select some of the larger ngon UV face Result: The selection of larger ngon UV faces fails in many cases Expected The UV faces under the mouse cursor are selected when clicked on [UVSelectBug.blend](https://archive.blender.org/developer/F14251984/UVSelectBug.blend) [2023-02-06 12-20-58.mp4](https://archive.blender.org/developer/F14251983/2023-02-06_12-20-58.mp4)

Ludvik Koutny commented

2023-02-06 12:24:00 +01:00

Added subscriber: @Rawalanche

Pratik Borhade commented

2023-02-07 05:45:44 +01:00

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

Pratik Borhade closed this issue

2023-02-07 05:45:44 +01:00

Pratik Borhade commented

2023-02-07 05:45:44 +01:00

Added subscribers: @PratikPB2123, @Chris_Blackbourn

Pratik Borhade self-assigned this 2023-02-07 05:45:44 +01:00

Pratik Borhade commented

2023-02-07 05:45:54 +01:00

Changed status from 'Resolved' to: 'Confirmed'

Pratik Borhade reopened this issue

2023-02-07 05:45:54 +01:00

Pratik Borhade removed their assignment 2023-02-07 05:46:03 +01:00

Philipp Oeser commented

2023-02-07 09:57:20 +01:00

Added subscriber: @lichtwerk

Philipp Oeser commented

2023-02-07 09:57:20 +01:00

Think this is because in the UV Editor, faces are actually selected by their center dot (unlike the 3D View).
@Chris_Blackbourn : can you confirm?

Think this is because in the UV Editor, faces are actually selected by their center dot (unlike the 3D View). @Chris_Blackbourn : can you confirm?

Ludvik Koutny commented

2023-02-08 10:09:03 +01:00

Think this is because in the UV Editor, faces are actually selected by their center dot (unlike the 3D View).
@Chris_Blackbourn : can you confirm?

Yes, but the issue here is that it doesn't make any sense in 2D space. Ngons can have their face center wildly outside their face area, so face selection becomes frustrating "find Waldo" game.

> Think this is because in the UV Editor, faces are actually selected by their center dot (unlike the 3D View). > @Chris_Blackbourn : can you confirm? Yes, but the issue here is that it doesn't make any sense in 2D space. Ngons can have their face center wildly outside their face area, so face selection becomes frustrating "find Waldo" game.

Philipp Oeser commented

2023-02-08 10:32:17 +01:00

Think this is because in the UV Editor, faces are actually selected by their center dot (unlike the 3D View).
@Chris_Blackbourn : can you confirm?

Yes, but the issue here is that it doesn't make any sense in 2D space. Ngons can have their face center wildly outside their face area, so face selection becomes frustrating "find Waldo" game.

I am with you here :)

> > Think this is because in the UV Editor, faces are actually selected by their center dot (unlike the 3D View). > > @Chris_Blackbourn : can you confirm? > > Yes, but the issue here is that it doesn't make any sense in 2D space. Ngons can have their face center wildly outside their face area, so face selection becomes frustrating "find Waldo" game. I am with you here :)

Chris Blackbourn commented

2023-02-08 23:37:08 +01:00

Think this is because in the UV Editor, faces are actually selected by their center dot (unlike the 3D View).
@Chris_Blackbourn : can you confirm?

Yes, this is indeed an issue.

I actually already have a "fix" for this :

https://archive.blender.org/developer/D15796

Any changes to selection are contentious. The question is do we :

A) Keep UV selection the same as 3D selection.
B) Change UV selection in 2D to work differently from 3D
C) Provide an option in preferences to choose either behavior.

From the code side, I can't really choose between the three options. Is there a way to reach a decision from the design side?

(In the interim, I'll fast-forward D15796 to master and import it in to the new system)

> Think this is because in the UV Editor, faces are actually selected by their center dot (unlike the 3D View). > @Chris_Blackbourn : can you confirm? Yes, this is indeed an issue. I actually already have a "fix" for this : https://archive.blender.org/developer/D15796 Any changes to selection are contentious. The question is do we : A) Keep UV selection the same as 3D selection. B) Change UV selection in 2D to work differently from 3D C) Provide an option in preferences to choose either behavior. From the code side, I can't really choose between the three options. Is there a way to reach a decision from the design side? (In the interim, I'll fast-forward D15796 to master and import it in to the new system)

Ludvik Koutny commented

2023-02-09 00:38:06 +01:00

It's a bit sad to see a "Needs design" response to https://archive.blender.org/developer/D15796

That usually means this will never be fixed and never make it to master. "Needs design" is universal Blender response to avoid responsibility for making a decision to fix something :(

Face center selection can be useful in the UV editor if multiple faces overlap, but are counter productive when there are no overlapping faces at the point of the click. Would it be possible to use following heuristic?:

If there is only one face under the mouse cursor click point, use the face area.
If there are multiple overlapping faces under the mouse cursor click point, use the face center which is nearest out of all the cursor hit faces.

I am not sure what the performance implications would be though.

It's a bit sad to see a "Needs design" response to https://archive.blender.org/developer/D15796 That usually means this will never be fixed and never make it to master. "Needs design" is universal Blender response to avoid responsibility for making a decision to fix something :( Face center selection can be useful in the UV editor if multiple faces overlap, but are counter productive when there are no overlapping faces at the point of the click. Would it be possible to use following heuristic?: 1. If there is only one face under the mouse cursor click point, use the face area. 2. If there are multiple overlapping faces under the mouse cursor click point, use the face center which is nearest out of all the cursor hit faces. I am not sure what the performance implications would be though.

Chris Blackbourn commented

2023-02-09 01:06:41 +01:00

I think performance for UV selection is a red herring, none of the proposals here are slow, and in the unlikely situation something is slow on large meshes, that would just be a bug that we would fix.

I think your proposal might interact with the "penalty" system, i.e. :

If you click on a face to select it, it should select it
If you the click on the exact same spot again, it will deselect that face, and choose the next best one instead.
Maybe this generalizes to more than one face? Not sure?

My understanding is that's how selection works in 3D, but TBH, I'm not using the software in this kind of way, nor do I use other 3D packages, so I'm not just familiar enough with how it ought to work.

TL;DR I'm a coder, not an artist.

I think performance for UV selection is a red herring, none of the proposals here are slow, and in the unlikely situation something is slow on large meshes, that would just be a bug that we would fix. I think your proposal might interact with the "penalty" system, i.e. : * If you click on a face to select it, it should select it * If you the click on the exact same spot again, it will *deselect* that face, and choose the next best one instead. * Maybe this generalizes to more than one face? Not sure? My understanding is that's how selection works in 3D, but TBH, I'm not *using* the software in this kind of way, nor do I use other 3D packages, so I'm not just familiar enough with how it ought to work. TL;DR I'm a coder, not an artist.

Philipp Oeser removed the

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UV Editor face select mode fails to select ngons reliably #104374