Smart UV project creates overlapping uv-coordinates I am having a UV-Sphere with 23k vertices and 25k faces. I used the Smart UV project to create UV-Coordinates but I was surpries to see that some of the faces are overlapping.



I was able to reproduce that behaviour with a simple plane, which I subdivided two times and then moved two vertices. The Smart UV Project's angle limit must be 89.00.



Is that a bug? I thought every face should have it's own uv-coordinates as well as texture space.

FYI: The first picture was done with Smart UV project Angle Limit 66.00.

UPDATE

This also happens when I use a Smart UV project on a uvsphere where the vertices are moved along their normal with a value out of a noise function.

This can't be right?
Smart UV Project simply doesn't guarantee non-overlapping UVs.

It doesn't detect or correct self-intersecting UV's within a UV-island.

Using lower angle limit will typically help to avoid this problem, but there are still cases it could happen.

If the possibility of overlapping UV's is unacceptable, you could use Lightmap-pack instead.



Note, in the example given - there is a lot of noise, One way to resolve could mitigate overlapping could be calculate the UV's on a less noisy version of the mesh:


Store the original vertex locations.
Smooth the vertices.
Execute Smart-Project
Restore the vertex locations.