does blender not know how to properly mirror UVs?

So I have this model that I created by starting off with a cube, cutting it in half. and then making a duplicate linked, mirror of that half. I then used extrusion modeleing to get the model done.

After I finished I made unlinked copies of each side, placed them in thier own layer, joined them, and then removed doubles. Which results in a complete model with no visible evidence that I “cheated” by mirroring one half.

Well except now when I place textures on it there is visible texture distortion where the 2 halfs meet. I can understand the texture not matching up because it’s not made for tileing. But this is different it’s like blenders uv just end and then it filles in the rest with the last pixel on the end of the uv. This creates a series of stretched lines all along the centerof the model.

I’ve tried high res textures, moveing the UV joints abit at the mirrored edge and it always shows up the same.

Keep in mind when I joined the 2 halfs blender seemed to know what I was trying to do and auto-stitched the UV’s from the 2 halfs together. (which would be awsome, if it worked…) So when I move a UV vertice there is only one, and not another one below it.

Using the mirror modifier would have been easier. That way you can sort out the uv on both half’s at the same time before joining.

As a test, select all the vertices along the centreline of the model, and move them more towards one half. If the distortion on that half is reduced then maybe the centreline vertices were moved at some stage.

Did you remember to remove doubles on the mesh?

That’s what duplicating linked does. Anything you do on one gets copied onto the other.

I also found out that sub-surfing does it, although I have no freaking idea why. it subsurfs the uv’s properly everywhere else on this model except the centerline.