extra UV seams where meshes overlap #39879

New Issue

Campbell Barton · 2014-04-24T14:34:36+02:00

trupelo commented

2014-04-24 14:34:36 +02:00

(Migrated from localhost:3001)

When 2 meshes have overlapping UV's, each edge turns into a seam resulting in unnecessary extra UV counts in game engines.
The work-around for me is to export from blender and sew the edges in maya.

I have been experiencing this since 2.68 when i started using Blender, so I'm sure this error is not specific to the new versions.

I have attached screenshots and obj files.
Please do fix this error.
exportFromBlender.obj

SewedInMaya.obj

Thank you so much :)

When 2 meshes have overlapping UV's, each edge turns into a seam resulting in unnecessary extra UV counts in game engines. The work-around for me is to export from blender and sew the edges in maya. I have been experiencing this since 2.68 when i started using Blender, so I'm sure this error is not specific to the new versions. I have attached screenshots and obj files. Please do fix this error. [exportFromBlender.obj](https://archive.blender.org/developer/F85811/exportFromBlender.obj) [SewedInMaya.obj](https://archive.blender.org/developer/F85810/SewedInMaya.obj) ![extra_seams_when_exported_from_blender.png](https://archive.blender.org/developer/F85806/extra_seams_when_exported_from_blender.png) ![after_sewing_uvs_in_maya.png](https://archive.blender.org/developer/F85807/after_sewing_uvs_in_maya.png) Thank you so much :)

trupelo commented

2014-04-24 14:34:36 +02:00

(Migrated from localhost:3001)

Changed status to: 'Open'

trupelo commented

2014-04-24 14:34:36 +02:00

(Migrated from localhost:3001)

Added subscriber: @trupelo

trupelo commented

2014-04-28 06:45:02 +02:00

(Migrated from localhost:3001)

Rin3.obj

here is another example of the same problem

since the model has overlapping uv's, each edge becomes a seam.
The vertex count remains the same but uv count goes up much higher- 653 uvs for 259 vertices while ideally it should be 321 uvs.

[Rin3.obj](https://archive.blender.org/developer/F86243/Rin3.obj) here is another example of the same problem since the model has overlapping uv's, each edge becomes a seam. The vertex count remains the same but uv count goes up much higher- 653 uvs for 259 vertices while ideally it should be 321 uvs.

Campbell Barton was assigned by Sergey Sharybin

2014-04-28 10:10:34 +02:00

Sergey Sharybin commented

2014-04-28 10:10:34 +02:00

Added subscribers: @ideasman42, @Sergey

Sergey Sharybin commented

2014-04-28 10:10:34 +02:00

@ideasman42, any ideas here?

Campbell Barton removed their assignment 2014-04-28 12:53:21 +02:00

Bastien Montagne was assigned by Campbell Barton

2014-04-28 12:53:21 +02:00

Campbell Barton commented

2014-04-28 12:53:47 +02:00

Added subscriber: @mont29

Campbell Barton commented

2014-04-28 12:53:47 +02:00

I expect this is caused by splitting normals, @mont29, could you check on this?

Bastien Montagne commented

2014-04-28 13:02:16 +02:00

Please attach the blend file from which you exported those obj…

Bastien Montagne commented

2014-04-28 13:03:26 +02:00

Also, is this an issue with OBJ exporter? or you have those over-UVs inside Blender?

trupelo commented

2014-04-29 12:05:08 +02:00

(Migrated from localhost:3001)

rin003.blend

Here is the blend file guys..

Blender does not display the uv count of an object. So, I cannot say whether these extra uv seams exist in blender, or they're created while exporting.

Rin3.fbx
Here is a .fbx of the same model exported from blender. It shows proper uv count (194 uvs) and perfect seams even in maya.

I would like to take this opportunity to request for uv count display in Blender alongside vertex, edge and face counts.

[rin003.blend](https://archive.blender.org/developer/F86374/rin003.blend) Here is the blend file guys.. Blender does not display the uv count of an object. So, I cannot say whether these extra uv seams exist in blender, or they're created while exporting. [Rin3.fbx](https://archive.blender.org/developer/F86375/Rin3.fbx) Here is a .fbx of the same model exported from blender. It shows proper uv count (194 uvs) and perfect seams even in maya. I would like to take this opportunity to request for uv count display in Blender alongside vertex, edge and face counts.

Campbell Barton commented

2014-04-30 02:11:41 +02:00

@trupelo - Blender doesn't have a UV count in the same way as Maya does. - So it doesnt really make sense to add this.

trupelo commented

2014-05-01 20:20:58 +02:00

(Migrated from localhost:3001)

Campbell, I do think Blender needs a UV count display. Game engines require optimal uvs for each object. I am eager to see this issue fixed and to see uv count display in blender.

I would like to add that, when we checked in Unity, importing the normals from the object raised the uv count by a few hundreds. But when the normals were not imported, it showed the correct number of vertices as exported from Blender.

Campbell, I do think Blender needs a UV count display. Game engines require optimal uvs for each object. I am eager to see this issue fixed and to see uv count display in blender. I would like to add that, when we checked in Unity, importing the normals from the object raised the uv count by a few hundreds. But when the normals were not imported, it showed the correct number of vertices as exported from Blender.

Campbell Barton commented

2014-05-01 21:46:37 +02:00

@trupelo, well this is beside the point (unrelated to the bug report), I just mention that Blender is not storing this data so its not a simple matter of adding some label to the interface.

blender-admin commented

2014-05-11 22:01:41 +02:00

This issue was referenced by blender/blender-addons@887fad6a01

This issue was referenced by blender/blender-addons@887fad6a0196be41aef358f8c8ff828b10f7898f

Bastien Montagne commented

2014-05-11 22:01:53 +02:00

Mmmmh… Not really a bug, in fact, Maya just create seems as soon as the UV values does not match exactly… :/

For now, will simply reduce the sensibility of the “same UV” test in obj exporter (was using values rounded to sixth decimal, will use values rounded to the forth one now, should be more than enough!

Mmmmh… Not really a bug, in fact, Maya just create seems as soon as the UV values does not match exactly… :/ For now, will simply reduce the sensibility of the “same UV” test in obj exporter (was using values rounded to sixth decimal, will use values rounded to the forth one now, should be more than enough!

Bastien Montagne commented

2014-05-11 22:04:29 +02:00

Changed status from 'Open' to: 'Resolved'

Bastien Montagne closed this issue

2014-05-11 22:04:29 +02:00

Bastien Montagne commented

2014-05-11 22:04:29 +02:00

Closed by commit blender/blender-addons@887fad6a01.

trupelo commented

2014-05-14 04:36:51 +02:00

(Migrated from localhost:3001)

Thank you, mont29.
Will these code changes be reflected in the next builder.blender.org build?

Thank you, mont29. Will these code changes be reflected in the next builder.blender.org build?

Bastien Montagne commented

2014-05-14 11:50:48 +02:00

@trupelo they most likely already are, yes.

Oliver M-H commented

2014-05-14 12:50:04 +02:00

Added subscriber: @malkavian

Oliver M-H commented

2014-05-14 12:50:04 +02:00

I don't think lowering decimal precision is the right way to go.
Maybe you can add an option to the .obj exporter to let the user specify the amount of decimal places? A simple checkbox for 2 presets (like full precision / half precision) would be fine I guess.

I don't think lowering decimal precision is the right way to go. Maybe you can add an option to the .obj exporter to let the user specify the amount of decimal places? A simple checkbox for 2 presets (like full precision / half precision) would be fine I guess.

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extra UV seams where meshes overlap #39879