I am having a very strange problem with an imported FBX model. If I place the lights in the model everything is ok but when I bake them the resulting lightmap is severely artifacted exposing the polygon lines. I have included two images below.
No baked lights:
With baked lights:
The horror!
As you can see this just doesn’t work. The lights are simple point lights placed close to the ceiling. They are set to “no shadows” and “bake only”. Everything else is default (color white, intensity 1). I am not doing anything special like ambient oclusion.
I haven’t encountered anything like this while searching the discussion. Why does the lightmap highlight my geometry like that?
My first guess is that the lightmapping UVs are incorrect. Are you sure they are not overlapping and inside UV spaces? What happens if you check “Generate Lightmapping UVs” on the imported model?
It is checked. If I don’t check “generate ligthmapping UVs” in the FBX importer the baked lightmap will just ignore the imported objects. If I put a plane in the scene the lights will pas right through the room and light up the plane as if it’s the only thing in the scene. Hold on I will get a screenshot in 30 minutes when I get to my PC.
Well looking a bit closer it seems like your model also has issues when no lights are baked. Just have a look at the upper left corner where the beam is at the ceiling - you can actually see that the same issues which become more clear on the baked lights version are also visible on the other version. So my next guess is that the normals of your mesh are not lined up, your mesh might even be split up into several parts as it seems. I recommend to check that next.
If that is the case you can actually smooth out the normals even across objects that are split. In 3ds Max you can do that by applying an Edit Normals modifier, go to the “average” tab, put a threshold and smooth them out.
Edit: And if that is the case, try to add some lightmap padding when generating those.
