Fixing Normal Map Seams

Baking normal maps for low-poly models may result in annoying seam lines, as shown in the image below.

Notice the seam lines: along the right arm, across the left shoulder, along the middle of the head.

These lines happen along the edges where I broke the UV. I thought this meant that the cause was related to the UV. The cause turns out to be gamma correction problem: the normal map should be read with gamma 1 instead of the default 2.2.

Reading the normal map with gamma 1.0.

And here is the fixed render.

Seam lines fixed.

Credit: I got this tip from this thread at CG Society forum: http://forums.cgsociety.org/showthread.php?t=1187474

There are many possible causes for a normal map problem. This is just one of them. If you have problems with your normal map, feel free to ask me either by commenting to this post or by sending me an email :)