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I have a mesh which is generated by another program with 100's of thousands of faces. I'd like to UV unwrap this mesh. All of the unwrap options take a very long time. So long that I'm quitting Blender before they complete. Which unwrapping method should finish the fastest?

The surface is created from an airflow simulation and is an iso-surface from a 3D flow like this:

enter image description here

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  • $\begingroup$ It could be that it would depend upon the mesh and the desired UV layout. $\endgroup$
    – brasshat
    Mar 24 '16 at 18:23
  • $\begingroup$ Can we get more info here? Such as what is the subject that you are trying to unwrap (a large scan data dump from something like meshlab), can it be simplified 1st (can you live with less info), etc... I personally do not know how to benchmark the methods of UV unwrapping, however some her on BSE may get you to your ultimate desired end result. $\endgroup$
    – Rick Riggs
    Mar 24 '16 at 18:26
  • $\begingroup$ The UV mapping is for baking colors to vertices, then using the colors to decimate the mesh. The UV mapping can be relatively poor as long as all vertices are mapped. Because of the mesh size, I need the fastest method that can be used on the mesh. $\endgroup$
    – Ed Tate
    Mar 24 '16 at 18:26
  • $\begingroup$ The mesh is an iso-surface from an airflow simulation. $\endgroup$
    – Ed Tate
    Mar 24 '16 at 18:27
  • $\begingroup$ @EdTate, Check this link, and see if the Z-Pass method would seem to help you. $\endgroup$
    – Rick Riggs
    Mar 24 '16 at 18:42
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The built in automatic method that takes the least time to complete is almost always "Unwrap." For a simple mesh of 300,000+ polys, it took about 10 seconds. "Light map pack" took about 20 seconds, and "Smart UV Project" took longer than 1 minute.

For your mesh, I don't doubt that it will take longer, but it shouldn't be hours (I'd think). It may actually help speed up the process to mark some arbitrary seams. If you can, select two points, then choose Select -> Shortest Path. That will give you a contiguous line of edges that you can then mark as a seam. Mark a couple of seams lengthwise to split it into dorsal and ventral halves, then maybe even into quarters. Splitting things up this way, usually helps "Unwrap" work faster, but doesn't have any effect on any of the other methods.

Hope that helps!

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