Smart UV Project creates overlapping uv-space #45520

New Issue

Michael Hamburger · 2015-07-22T11:38:48+02:00

Michael Hamburger commented

2015-07-22 11:38:48 +02:00

System Information
Windows 8.1 x64
AMD HD 7870

Blender Version
2.75a x64

Short description of error
I am writing a Add-On which procedurally generates a mesh. The mesh can have a lot of spikes. I used Smart UV Project for creating UV-Coordinates and saw that the texture space is sometimes overlapping with another texture space of a different face. I know that I could mark seams manually but I want that the mesh and the UV-Coordinates are created automatically.
I was able to reproduce this with a simple plane.

Exact steps for others to reproduce the error

Create a Plane at x,y,z = 0
Subdivide the Plane two times
Select one vertex and translate it along the z-axis at position greater than 1.
Select the vertex after the next vertex of the already moved vertex (I hope you understand what I mean) and translate it along the z-axis at position greater than 1.
Select the mesh, use smart uv project with angle limit set to 89.00 (FYI: Normally I use 66.00 but the behaviour can be forced with the limit set to 89.00)
In the UV/Image Editor you can see overlapping texture spaces. I think that isn't correct, isn't it? I thought UV Mapping is a one-to-one mapping.

I posted the bug also on blender.stackexchange.org (http://blender.stackexchange.com/questions/34300/smart-uv-project-creates-overlapping-uv-coordinates)

Blend-File: Smart_UV_Project_overlapping.blend

**System Information** Windows 8.1 x64 AMD HD 7870 **Blender Version** 2.75a x64 **Short description of error** I am writing a Add-On which procedurally generates a mesh. The mesh can have a lot of spikes. I used Smart UV Project for creating UV-Coordinates and saw that the texture space is sometimes overlapping with another texture space of a different face. I know that I could mark seams manually but I want that the mesh and the UV-Coordinates are created automatically. I was able to reproduce this with a simple plane. **Exact steps for others to reproduce the error** 1) Create a Plane at x,y,z = 0 2) Subdivide the Plane two times 3) Select one vertex and translate it along the z-axis at position greater than 1. 4) Select the vertex after the next vertex of the already moved vertex (I hope you understand what I mean) and translate it along the z-axis at position greater than 1. 5) Select the mesh, use smart uv project with angle limit set to 89.00 (FYI: Normally I use 66.00 but the behaviour can be forced with the limit set to 89.00) 6) In the UV/Image Editor you can see overlapping texture spaces. I think that isn't correct, isn't it? I thought UV Mapping is a one-to-one mapping. I posted the bug also on blender.stackexchange.org (http://blender.stackexchange.com/questions/34300/smart-uv-project-creates-overlapping-uv-coordinates) Blend-File: [Smart_UV_Project_overlapping.blend](https://archive.blender.org/developer/F211564/Smart_UV_Project_overlapping.blend)

Michael Hamburger commented

2015-07-22 11:38:48 +02:00

Changed status to: 'Open'

Michael Hamburger commented

2015-07-22 11:38:48 +02:00

Added subscriber: @Haembi

Campbell Barton commented

2015-07-27 04:14:59 +02:00

Added subscriber: @ideasman42

Campbell Barton commented

2015-07-27 04:14:59 +02:00

Changed status from 'Open' to: 'Archived'

Campbell Barton closed this issue

2015-07-27 04:14:59 +02:00

Campbell Barton self-assigned this 2015-07-27 04:14:59 +02:00

Campbell Barton commented

2015-07-27 04:14:59 +02:00

This isn't a bug, in that smart-projection doesn't guarantee no overlapping.

I realize this is a contrived example. and other more subtle cases may still overlap, and it would be nice to detect and correct for this.

However the tool just doesn't support this at the moment.

An alternative is lightmap-pack which ensures no overlap, but won't share UV-vertices.

closing.

This isn't a bug, in that smart-projection doesn't guarantee no overlapping. I realize this is a contrived example. and other more subtle cases may still overlap, and it would be nice to detect and correct for this. However the tool just doesn't support this at the moment. An alternative is lightmap-pack which ensures no overlap, but won't share UV-vertices. closing.

Michael Hamburger commented

2015-07-27 11:49:34 +02:00

I am sorry but that is not a contrived example! I am writing a procedural mesh generator where software agents are moving vertices along their normal. And sometimes two spikes are next to each other.

In the Blender.Stackexchange-Link you can also see a UV Sphere and the error occured there too. And UV Spheres are often used in Low Poly games.

I am sorry but that is not a contrived example! I am writing a procedural mesh generator where software agents are moving vertices along their normal. And sometimes two spikes are next to each other. In the Blender.Stackexchange-Link you can also see a UV Sphere and the error occured there too. And UV Spheres are often used in Low Poly games.

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Smart UV Project creates overlapping uv-space #45520