Smart UV Project - small faces packed into a single point #48086

Closed
opened 2016-04-08 09:36:33 +02:00 by Marcin Twarowski · 9 comments

System Information
Windows 7 and 10, GeForce GTX 970

Blender Version
2.77a

Short description of error
Small faces are packed into a single point in a left bottom corner of uv space when using Smart UV Project. When the same object is scaled up the problem doesn't occur. The model was originally created in CAD program, and exported from 3ds max to fbx.

Exact steps for others to reproduce the error
Select object "b". In edit mode press "u". Use Smart UV Project. Area weight 0 gives overlapping islands, 1 gives better results, but in both cases there are zero area islands (see picture): smart_uv_project_bug_01.png Object "a" is the same model but scaled up that doesn't produce the same error.
test blend file: smart_uv_unwrap_bug_2.77.blend

**System Information** Windows 7 and 10, GeForce GTX 970 **Blender Version** 2.77a **Short description of error** Small faces are packed into a single point in a left bottom corner of uv space when using Smart UV Project. When the same object is scaled up the problem doesn't occur. The model was originally created in CAD program, and exported from 3ds max to fbx. **Exact steps for others to reproduce the error** Select object "b". In edit mode press "u". Use Smart UV Project. Area weight 0 gives overlapping islands, 1 gives better results, but in both cases there are zero area islands (see picture): ![smart_uv_project_bug_01.png](https://archive.blender.org/developer/F301393/smart_uv_project_bug_01.png) Object "a" is the same model but scaled up that doesn't produce the same error. test blend file: [smart_uv_unwrap_bug_2.77.blend](https://archive.blender.org/developer/F301395/smart_uv_unwrap_bug_2.77.blend)

Changed status to: 'Open'

Changed status to: 'Open'

Added subscriber: @MarcinTwarowski

Added subscriber: @MarcinTwarowski

Added subscribers: @brecht, @mont29

Added subscribers: @brecht, @mont29

You are probably hitting float precision limits here? CAD exports have really horrible geometries…

@brecht maybe you have better insight on possible causes of that issue?

You are probably hitting float precision limits here? CAD exports have really horrible geometries… @brecht maybe you have better insight on possible causes of that issue?

Added subscriber: @ideasman42

Added subscriber: @ideasman42

@ideasman42 wrote this operator I think, I'm not familiar with this code. I don't think float precision limits are the issue here, it's not that extreme a difference in scale.

Selecting just those vertices in the corner and trying to use Smart UV project on those also gives me an error:

Traceback (most recent call last):
  File "scripts/startup/bl_operators/uvcalc_smart_project.py", line 1092, in execute
    self.stretch_to_bounds
  File "scripts/startup/bl_operators/uvcalc_smart_project.py", line 852, in main
    newProjectVec = meshFaces[0].no
IndexError: list index out of range
@ideasman42 wrote this operator I think, I'm not familiar with this code. I don't think float precision limits are the issue here, it's not that extreme a difference in scale. Selecting just those vertices in the corner and trying to use Smart UV project on those also gives me an error: ``` Traceback (most recent call last): File "scripts/startup/bl_operators/uvcalc_smart_project.py", line 1092, in execute self.stretch_to_bounds File "scripts/startup/bl_operators/uvcalc_smart_project.py", line 852, in main newProjectVec = meshFaces[0].no IndexError: list index out of range ```

This is caused by fix for #31598... will see if there is some reasonable limit for small faces that works for both.

This is caused by fix for #31598... will see if there is some reasonable limit for small faces that works for both.

Changed status from 'Open' to: 'Resolved'

Changed status from 'Open' to: 'Resolved'

This issue was referenced by 4ee5ba41bb

This issue was referenced by 4ee5ba41bbd669ae4c9b57129c9711d2def41540
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Reference: blender/blender#48086
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