Is unity ok with symmetrical overlapping uv’s?
Further explanation…
I take a model and I lay out it’s uv’s. Then I delete half of it and then apply symmetry. This results in the uv’s for the left half of the body to rest directly over the right half of the body.
This saves space and allows you to have more detail in most cases.
Does unity have any kind of problem with this technique?
I’m not sure what you mean by “delete half”, but you can do whatever you want with UVs. I understand the result you’re talking about; overlapping presents no problem. I just don’t know what you’re deleting.
i guess you mean 3ds max symmetry modifier? or any common symmetry.
and yes it works.
its lightmap that you should not overlap.
i have had no problems with uv’s overlapping on color map.
So unity doesn’t mind if you overlap uv’s?
Hah, I made an edit while you typed. 
No problem whatsoever.
A “lightmap” is just a texture that gets multiplied in based on another UV set. It doesn’t generally make much sense to do overlapping here, especially if you’re baking in an external 3D app based on a lighting rig, but there’s nothing that specifically presents a problem here, if you care to control your overlap for whatever reason.
An alternative to overlapping is to place the UVs that would overlap somewhere outside 0-1, but it’s not necessary. And it’s not desirable, if you can avoid it, because that will actually double up the vertex count for anything along the line of symmetry.
You will be twice as fast with your modeling work if you model with a symmetry modifier from the start. That way you only have to model half of your object and lay out half your uv’s. If you just don’t like to model that way at least delete half your model before laying out the uv’s then add the symmetry modifier.
I"m having problems. I’m going to bump this thread.