[Baked GI] Severe Lighting Artifacts at UV Seams

Unity Engine
1

As the title indicates, I get severe artifacts at UV seams when using baked GI:


All meshes and the only light source (a directional light, no shadows) are set to static, and I’ve used a freshly created material (standard shader with default values). The two humans have different UV mappings, but both have the problem (it’s even worse when letting Unity create the lightmap UVs). The sphere is a Unity default sphere.
The models look perfect in Maya, the normals are also well defined (letting Unity create the normals / tangents makes no difference). Increasing the quality settings has no effect.

When I switch everything to realtime, the problem disappears - what’s going on here? I find it hard to believe the GI baking system in Unity can’t even handle a simple sphere with 1 directional light, and no ambient / sky light whatsoever… Is this a bug?

Here is a second screenshot (everything the same, only different light direction & view direction):

The issue is not only the seams, but it really seems that complete UV patches are lit wrongly. It almost looks like a SSS effect (the light is shining from above, so the leg illumination is completely wrong).

Here is a screenshot in a more “busy” scene:

Any help would be greatly appreciated, this is a time-critical project.

PS: I’m working with Unity 5.5.0f3 (64 bit) on a Windows 10 machine. I am using the SteamVR plugin in this project, but was able to reproduce the issue in an empty project.

2

Just unwrap your lightmap UV’s as one large island/pelt.

3

Thanks for your answer.

Is that a workaround or the expected workflow? I would honestly be shocked if the second were the case in 2016 - if Enlighten is not able to handle UV patches with halfways acceptable results then I wonder why anyone would use Unity with GI.

I mean, if you look at the second screenshot again, the lighting is completely wrong - this must be a bug, right??

PS: I’m pretty sure that even having a single UV patch will produce wrong results at the seams - e.g. the leg of the model is a single patch, and the lighting does not match at all at the seams. It is also not a bug with the dilation, since the wrong lighting continues towards the middle of the leg…