Unity 5 lightmap: Why it's generating dark lines showing the model's wireframe?

This happens when I change object’s resolution. It was happening on another object, then I changed it’s resolution than it fixed, but messed up with this ones below. I’m sure the UV is correct and there are no polygons touching the bounds or overlapping, because it worked fine on Unity 4.6 and sometimes it works on Unity 5 as well, depending on the object resolution.

Is there a workaround for this?

It’s directional lightmaps, but this spots show on intensity and directional lightmap.


I had the same problem until I found the following post where dns says to go into the Import Settings of your imported models and turn on Generate Lightmap UVs. Immediately fixed the issue and lightmaps generate perfectly now.


Had the same problem too. It;s most likely due to the uv problem. Try to turn on generate lightmap uvs or turn off Preserve UVs & adjust auto UV distance in Lighting panel should fix that problem