Lightmapping issue, black lines between meshes

Unity Engine
1

Hi, I recently reworked my entire leveldesign to get more performance due occlusion culling so I set up my level modular. I am using an Area Light to light up that room. Now I get the lightmapping not working properly. Between my objects I get black lines. There is definatly no gap between the two objects due to the fact I used maya to lay the level down and check every single vertex between the objects laying to each other. They look kinda there are connected but they are not. There is also no difference in height. As well as I turned off all shadows via quality settings, so if those lines are supposed to be shadows by any chance I dont get it. Here is a screenshot of my problem:

I played around with the lighting settings a lot and just If I crank up Baked Resolution to 100 the lines are getting less visible but the lightmap data increases drastically and that has a bad impact on batching and set pass calls. And I need to be as low as possible regarding draw calls due to the fact its a mobile VR setup! Here my lighting settings:

I also played around with the import settings of my meshes. Under Generate Lightmaps Advanced Tab I changed the settings like here:

Now its way better but I still get those black lines somewhere… no clue what to do next!

As you can see the lines on the floor are barey visible anymore, but there is still a black one between the doors?!?!

Anyone has an idea how to solve this? Before I pull my hair out… :wink:

2

Well, the lightmapper kind of sucks. It doesn’t fill the empty space with nearest neighbor colors, so everything outside it seems to be black, so with a low res it will bleed into your lightmap. Even engines from 1997 don’t have this problem with much lower lightmap resolutions.

Try merging your meshes together into one object, instead of everything being modular. The floor having 2 polygons will also solve it.

Try putting “Baked Padding” to 8 texels, and increasing lightmap resolution.

Try making the lightmap texture’s ansitropic filtering higher. Default is 3. You will see a difference between 0 and 3. Try 9 or something. The lightmap files will be in a folder named after you scene if your disable Auto building.

1 Like
3

Lightmapping with modular pieces must be careful. An ant size offset will make seams appear.
You must separate lightmap UV shell on each faces If your floor / wall model is a cube object.
And make sure the smoothing group / soft-hard edge is separated for all those faces.