Cycles & BI have broken UVs in some degenerated quads cases #47198

New Issue

Guillaume Lussier-Dulude · 2016-01-18T01:34:56+01:00

2016-01-18 01:34:56 +01:00

System Information
Operating system and graphics card
Windows 10
NVIDIA GeForce GTX 770

Blender Version
Broken: (2.76b f337fea)

Short description of error
The viewport shading texture or material is different from the render after I UV Unwrap my mesh.

Exact steps for others to reproduce the error
1- I create a spin from an edge (in the mesh tool) because a want creates a street in 90 degrees.
2- I UV Unwrap the asphalt part of my street and I adjust the UV to be more rectangle and ajust with the curve of my street.

Every time I UV Unwrap, the render is glitches and it looks like every polygon has its own UV. Even after creating another project.

The only way I discover to “remove” this bug is:
1- Use the mirror modifier and press the apply button.
2- And remove the old mesh or there a bug
So basically, I use the objet create by the modifier because the UV work properly.

Thank you

**Here my file** [Route1.blend](https://archive.blender.org/developer/F275043/Route1.blend) ![ImageDemonstration.jpg](https://archive.blender.org/developer/F275044/ImageDemonstration.jpg) **System Information** Operating system and graphics card Windows 10 NVIDIA GeForce GTX 770 **Blender Version** Broken: (2.76b f337fea) **Short description of error** The viewport shading texture or material is different from the render after I UV Unwrap my mesh. **Exact steps for others to reproduce the error** **1-** I create a spin from an edge (in the mesh tool) because a want creates a street in 90 degrees. **2-** I UV Unwrap the asphalt part of my street and I adjust the UV to be more rectangle and ajust with the curve of my street. Every time I UV Unwrap, the render is glitches and it looks like every polygon has its own UV. Even after creating another project. **The only way I discover to “remove” this bug is:** **1-** Use the mirror modifier and press the apply button. **2-** And remove the old mesh or there a bug So basically, I use the objet create by the modifier because the UV work properly. Thank you

Guillaume Lussier-Dulude commented

2016-01-18 01:34:56 +01:00

Changed status to: 'Open'

Guillaume Lussier-Dulude commented

2016-01-18 01:34:56 +01:00

Added subscriber: @GuillaumeL-D

Bastien Montagne commented

2016-01-19 14:46:12 +01:00

Added subscriber: @mont29

Bastien Montagne commented

2016-01-19 14:46:12 +01:00

Can confirm that issue, with both Cycles and internal, and in current master as well, weird… :/

Bastien Montagne self-assigned this 2016-01-19 14:46:26 +01:00

Bastien Montagne commented

2016-01-19 15:05:53 +01:00

Problem is coming from those degenerated triangles you are creating with those quads-as-tris 'trick'. Looks like during tessellation, UVs from 'degenerated' tri are used, instead of 'good' ones.

Also interesting, if you mirror the mirror copy, you have the issue again.

Problem is coming from those degenerated triangles you are creating with those quads-as-tris 'trick'. Looks like during tessellation, UVs from 'degenerated' tri are used, instead of 'good' ones. Also interesting, if you mirror the mirror copy, you have the issue again.

Bastien Montagne commented

2016-01-19 19:40:39 +01:00

Added subscribers: @Sergey, @brecht, @ThomasDinges

Bastien Montagne changed title from ~~The viewport shading texture or material is different from the render after I UV Unwrap my mesh.~~ to Cycles & BI have broken UVs in some degenerated quads cases

2016-01-19 19:44:14 +01:00

blender-admin commented

2016-01-20 10:03:14 +01:00

This issue was referenced by bf5ddb9728

This issue was referenced by bf5ddb9728ef3eeed680399ab4d0f7aa59fe1fa4

Bastien Montagne commented

2016-01-20 10:17:12 +01:00

Changed status from 'Open' to: 'Resolved'

Bastien Montagne closed this issue

2016-01-20 10:17:12 +01:00

Sign in to join this conversation.

No Label

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Cycles & BI have broken UVs in some degenerated quads cases #47198