UV island select won't select contiguous faces when the polygons UV data flips from positive to negative inside an island
Closed, ResolvedPublic

Description

System Information
windows 10, 2600k, gtx 970

Blender Version
Broken: 2.75 onwards
Worked: 2.74

Short description of error
When trying to island select UVs, if a polygon UV is "flipped" compared to the initially selected faced the island select will ignore the flipped face.

by flipped I mean the texture appears backwards or upside down compared to the texture UVs on a non flipped face

Exact steps for others to reproduce the error

Create a box
UV unwrap > project from view
Go to UV window
Island select the box
Move selection
Notice, the box is split in half
Expected, the box keeps together

2.75 onwards = https://dl.dropboxusercontent.com/u/1693140/uvs.gif

2.74 = https://dl.dropboxusercontent.com/u/1693140/uvs2.gif

example of real world usage = https://dl.dropboxusercontent.com/u/1693140/uvleftbehind.gif

notes

it was hard to tell if this is a design decision, if so would be great to have the old select back as an option

This was caused by fix bca4e9c81d86
It seems that the use_winding option of BM_uv_vert_map_create is not working correctly.

Note that for meshes we have option to delimit: Normal, Material, Seam... etc.

If this is made optional would be nice to keep similar convention,
Although we really miss having a redo-toolbar for uv operators.

Bastien Montagne (mont29) triaged this task as "Confirmed" priority.Tue, Jul 4, 5:43 PM