UV symmetry?

[mireazma]

Hi there. I marked edges for cut and then unfolded a symmetrical obj. It turned up pretty good with left and right sides symmetrically placed on the UV map as expected. There were some barely visible differences though. When I mirrored one island and placed over the other they didn't match perfectly. If I hadn't mirrored and overlap them I could swear they were perfectly symmetrical.
Question: does anyone know of a trick to make them fit 100%?

[micheus]

I'm not sure that is the right approach, but that is how I use to do when using mirrored objects.

I use to finish it (sometimes I make a backup first), but before I use Tools->Virtual Mirror->Freeze I unwrape the mesh. Just after that I freeze it and then on AutoUV window I cut the half segments and flip them to get the unfolded mesh symmetrical.

Here is a gif showing what I'm talking about: