Maniphest T48086

Smart UV Project - small faces packed into a single point
Closed, Resolved
Actions

Assigned To
None
Authored By
Marcin Twarowski (Tvaroog)
Apr 8 2016, 9:36 AM
Tags
  • BF Blender
Subscribers
Bastien Montagne (mont29)
Brecht Van Lommel (brecht)
Campbell Barton (campbellbarton)
Marcin Twarowski (Tvaroog)

Description

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):

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.blend3 MBDownload

Revisions and Commits

rB Blender
rB4ee5ba41bbd6 Fix T48086: Smart UV Project fails w/ small faces

Related Objects

Event Timeline

Marcin Twarowski (Tvaroog) created this task.Apr 8 2016, 9:36 AM
Marcin Twarowski (Tvaroog) raised the priority of this task from to 90.
Marcin Twarowski (Tvaroog) updated the task description.
Marcin Twarowski (Tvaroog) added a project: BF Blender.
Marcin Twarowski (Tvaroog) edited a custom field.
Marcin Twarowski (Tvaroog) added a subscriber: Marcin Twarowski (Tvaroog).
Bastien Montagne (mont29) lowered the priority of this task from 90 to 50.Apr 8 2016, 4:14 PM
Bastien Montagne (mont29) added subscribers: Brecht Van Lommel (brecht), Bastien Montagne (mont29).

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

@Brecht Van Lommel (brecht) maybe you have better insight on possible causes of that issue?

Brecht Van Lommel (brecht) added a subscriber: Campbell Barton (campbellbarton).Apr 9 2016, 12:14 AM

@Campbell Barton (campbellbarton) 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
Campbell Barton (campbellbarton) added a comment.Apr 20 2016, 3:10 AM

This is caused by fix for T31598... will see if there is some reasonable limit for small faces that works for both.

Campbell Barton (campbellbarton) changed the task status from Unknown Status to Resolved by committing rB4ee5ba41bbd6: Fix T48086: Smart UV Project fails w/ small faces.Apr 20 2016, 3:49 AM
Campbell Barton (campbellbarton) added a commit: rB4ee5ba41bbd6: Fix T48086: Smart UV Project fails w/ small faces.