Align UV map island with axis or other island I have following UV map!



Those islands are both same, but one of them is mirrored. I can mirror the one of the parts by selecting UVs -> Mirror -> X Axis (Ctrl-M)

however the hard part is they are not aligned and even rotating one does not make it exactly match the other one and it leaves stretched marks when rendering on one side of the model.

I have found this forum post about almost same issue (different blender version) which does not have a proper answer either.

I tried using snap with vertex but still no luck properly overlapping two islands.

Is there anyway to align islands to X, Y axis or other model?
Change the snapping from increment to vertex 

Select an island with L
Choose one of the vertices on the island and match it to the corresponding one on the other island



If they are not aligned due to rotation, continue with these steps


Select the vertex that matches the island you are aligning to. 
Use Shift-S to snap the cursor to the selected vertex
Select the one island with L
Use . to set the pivot point to be the cursor
Rotate the island until R and snap a vertex that isn't lined up with the cursor to the similar one on the other mesh.



If the scale doesn't match proceed further these steps


With the pivot point still at the cursor at the matching vertex, hit S to scale until it snaps into place


If the map is distorted, or something above didn't work right, do these procedures instead of the above steps


Snap each vertex individually to the corresponding vertex using G.



Note: if the snapping doesn't work, try holding down Ctrl