My question is related to all the meshes that have been created with the modifier mirror.
Let's take an easy example:
This mesh can be divided in 2 parts, PART A & PART B: equal shape.
In order to optimize the space for my Normal map
1) i delete the PART A of my low poly / high poly
2) In this way, having only PART B, i unwrap PART B and bake it with the high poly
the results is this one; not so good but it's not the point of my question
3) i mirror my mesh in order to create again my PART A and i have now this one
4) as you can see the Uv map of PART A overlap, in the same position for each island, the uvmap of PART B and then they share the same portion on normal map
When i watch the final render however i saw this result
There is a line that cut my mesh in the half. Is it possibile to fix this problem? Does this prove that it's impossible to overlap two identical uv maps?