Light Bake issues, don't know what settings to modify

Hello Everybody!

I have some light bake issues, detail problems but just big enough to make it annoying

Here for example, my building is centric-symmetrical, but the error comes out exactly the same way on all the element. The pattern of these spoches is the same on all of them. Increasing the resolution doesn’t get rid of it, just becomes more defined. There are no errors with the geometry at all, I even streched the uvs there to give it more sample pixels, but the error stays the same.

The second issue is with this slightly curved wall, slight poches appear here as well

Otherwise on geometry details the resolution doesn’t seem to be big enough, even though i gave pretty large lightbake map size to them (128 / 256)

This is my lightbake settings, already increased higher than default.


Please help, this is really out of my reach, I don’t know what setting does what exactly to remove these troubles…


I’m not sure what quality you’re after but 128/256 resolution lightmaps are maybe large in low res games but nowhere else… you set lighting information in pixels here…
Also overlapping meshes like your light switch will never produce clean results…
Again I’m not sure about the quality you’re trying to achieve… your accuracy right now is 1 cm + a lot of blur…
Is your lightmap compression turned on? That also causes “dirty” results…
…also if you could tell what lights are you using in the scene with mobility…

Hello! the lightmap size of 128 / 256 refers to the switches on the wall only, the general lightmap on walls are 2048. That should not be the issue. Compression is off. There are no lights in the scene with mobility. What I would like to know if anybody has some experience with bakes with these kind of errors, because i don’t even know what causes them. I have a light importance volume as well. Doesn’t seems to be related to resolution, I’m baking now with much higher settings, i have to see what comes out. What do you mean by a lot of blur? Smoothness is set to 1. That’s a lot?

Every light has mobility… so I’m guessing from your answer you have only static lights in your scene… ? What lights do you have?
Could you show the lightmap uv of the problematic meshes?
Yes 1 is a lot… specially if you’re doing archviz! 0.6 will keep all your calculated shadows/lighting resolution accurate…

Oh and the switch… it looks like where you have the seams: you have a cut in your lightmap uv too… Try to keep flat/continuous areas together on your uv maps to avoid seams! + don’t use overlapping/polygon snapping meshes…

Yes, sorry, I meant that all my lights are static. Lightmap resolution is 2048

Ok, so I quickly put a 2048 res checker on your uv to show you how low resolution your lightmap is for this mesh!
I could make out exactly what part is what part but around the area your arrow is pointing: your surfaces get like a 5-10 pixel wide information!! …and the tinier ones even lower ones!
If you want to do archviz you should break up your buildings into smaller parts! Not that you can assign lightmap resolution more accurately but the calculation will be faster too since many lower res lightmaps are calculated faster then 1 big one!

Hm, don’t you think 10 pixel is enough for that little stripe? How the light bake looks on it is really fine for me, i just have problem with this spot that generates. Actually i have this piece repeating 8 times, and this issue looks exactly the same on all of them. Once I baked a 4k map on this object, and this spot was still there, just higher resolution.

I streched the uv on this part on purpose to try to give even more pixels for the area, thinking it might solve it, but it didn’t. That’s why it’s compressed looking.

Lightmap density looks totally ok! …just in case you can try it without stretching the area…
…have you tried with some other material? Something plain, no reflection at all?
Could you show the lighting only mode too please?
I see they are also on that circular mesh: are they at the same height as on the window parts?

Those splotches on the circular / arcing pieces above could be skylight cubemap indiscrepancies. Is DFAO enabled in the skylight?

“… all my lights are static…”

Thank you everybody for answering, I fixed it. apparently the Level scale has to be reduced, in my case all errors went away with a level scale of 0.2. Of-course my baking time went up 8x the time, but whatever, at least my baking is clean.

There’s a popular tutorial that claims that Level Scale multiplied by Indirect Quality must be equal to or close to 1. So, 1 x 4 (your settings previously) is 4, which probably stretched / skewed the lighting result in the data mapping to the lightmaps / surfaces. Or something about it messed it up. 0.2 x 4 = 0.8, which is closer to 1. Quality increases the sampling factor, while Level Scale modifies the density at which lighting is projected per unit. So if Level Scale 1 is per 1 Unreal Unit, or 1 centimeter, and Quality is at 4, then perhaps it is too much sampling for that 1 cm scale.