WIP. Blender add-on - copy/paste UV islands. Some theory behind.

Here it is example of simple mesh unwrap. As you can see we have 3 pairs of identical UV islands. In most of the cases we can pack each pair in the same UV space thus increasing texture space used for other details.
In 3d-Coat process look like selecting one UV island, pressing Ctrl-C (copy), then selecting similar island and pressing Ctrl-V (paste). Both islands at this moment using the same texture space. If we have more then two islands we can pack them one by one.
The main problem is that we need to find "symmetrical" vertexes for both islands and copy UV coordinates from one vertex to "paired" one.
So how can we do it. After some meditation I found that we need to iteratively compare border loops for both islands vertex by vertex and find shortest path between them - pair with shortest path should be "symmetrical". This concept needs poof code - so I return to this theme as soon as I write simple prototype for future add-on.

WIP. Blender add-on - copy/paste UV islands. Stacking of symmetrical geometry.

There is nice piece of software called 3D-Coat. Studying tutorials I found nice feature it used - namely copy/paste of UV islands. I found lack of this feature in Blender. Following link you can find more details about this, here I quote only essentials.

Stacking of symmetrical geometry - often times geometry that is exactly the same we will want to use the same image/texture data to save memory however, aligning the uv islands so they exactly overlap can be tedious. This would allow automatic alignment of UV islands for mirrored/symmetrical geometry.

I think it can be realized by add-on, and here I will post my WIP on this project.
P.S. for Russian speaking friends I also placed post here.