Texture distortions near a seam WITH some Mean Bevel Weight applied #91798

New Issue

Santiago Luib III · 2021-09-29T03:14:10+02:00

Santiago Luib III commented

2021-09-29 03:14:10 +02:00

System Information
Operating system: Windows 10 64-bit
Graphics card: GTX 1080Ti

Blender Version
Broken: 2.93.3
Worked:

On a concave surface, texture distorts near a seam edge with a bit of Mean Bevel Weight applied.

Create a curvy concave vessel/cup/pot with thickness.
Add Bevel modifier 0.1m amount, segments 2, Weight method
Make the mouth rim edges to be seams, and apply about 0.10 - 0.25 mean bevel weight
you can do the same on the base outer edge
UV unwrap, create image, better with 2048 and with UV Grid to see effect, apply to mesh

Notice the texture distorts near the outer seam edge of the concave surface (the outer skin of the pot/cup)
Setting the Mean Bevel Weight back to 0 removes this phenomenon but defeats the bevel purpose.
I made 3 blender files and all exhibit same "problem".

bugreport2.blend

**System Information** Operating system: Windows 10 64-bit Graphics card: GTX 1080Ti **Blender Version** Broken: 2.93.3 Worked: On a concave surface, texture distorts near a seam edge with a bit of Mean Bevel Weight applied. 1) Create a curvy concave vessel/cup/pot with thickness. 2) Add Bevel modifier 0.1m amount, segments 2, Weight method 3) Make the mouth rim edges to be seams, and apply about 0.10 - 0.25 mean bevel weight 4) you can do the same on the base outer edge 5) UV unwrap, create image, better with 2048 and with UV Grid to see effect, apply to mesh Notice the texture distorts near the outer seam edge of the concave surface (the outer skin of the pot/cup) Setting the Mean Bevel Weight back to 0 removes this phenomenon but defeats the bevel purpose. I made 3 blender files and all exhibit same "problem". [bugreport2.blend](https://archive.blender.org/developer/F10660662/bugreport2.blend)

Santiago Luib III commented

2021-09-29 03:14:10 +02:00

Added subscriber: @SantiLuib3

Santiago Luib III commented

2021-09-29 03:16:28 +02:00

Hi,

Please look into this, what I think is a bug? Thanks!

Cheers
Santi

Hi, Please look into this, what I think is a bug? Thanks! Cheers Santi

Richard Antalik commented

2021-09-29 16:52:51 +02:00

Added subscriber: @iss

Richard Antalik commented

2021-09-29 16:52:51 +02:00

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

Richard Antalik commented

2021-09-29 16:52:51 +02:00

Can confirm, ths looks like a bug though not 100% sure about that

Germano Cavalcante commented

2021-09-29 17:02:29 +02:00

Added subscribers: @Sergey, @mano-wii

Germano Cavalcante commented

2021-09-29 17:02:29 +02:00

@SantiLuib3, have you tried the different UV Smooth options?
See https://docs.blender.org/manual/en/dev/modeling/modifiers/generate/subdivision_surface.html#advanced

However some UVs apparently don't slide as expected.
I'm also not sure if it's really a bug.
If I'm not mistaken, @Sergey has worked on this subdvision UV area before.

@Sergey, (when you have time) can you confirm if this is a bug?

@SantiLuib3, have you tried the different `UV Smooth` options? See https://docs.blender.org/manual/en/dev/modeling/modifiers/generate/subdivision_surface.html#advanced However some UVs apparently don't slide as expected. I'm also not sure if it's really a bug. If I'm not mistaken, @Sergey has worked on this subdvision UV area before. @Sergey, (when you have time) can you confirm if this is a bug?

Sergey Sharybin commented

2021-09-29 17:25:35 +02:00

Seems more of a limitations of the currently supported UV smoothing.
The smoothing is done by OpenSubdiv. The Keep Boundaries is the closest to our own algorithm from 2.79, and the 2.79 has similar distortion.

There might be some other algorithm which will preserve the UV map, but looking into it and implementing it is not really a part of bug fixing.

Seems more of a limitations of the currently supported UV smoothing. The smoothing is done by OpenSubdiv. The `Keep Boundaries` is the closest to our own algorithm from 2.79, and the 2.79 has similar distortion. There might be some other algorithm which will preserve the UV map, but looking into it and implementing it is not really a part of bug fixing.

Philipp Oeser removed the

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Texture distortions near a seam WITH some Mean Bevel Weight applied #91798