decrease artifacts with compressed lgihtmaps

I’m trying to optimize my lightmaps for my mobile game, and compression is a great way to save myself a lot of file space (it chops 30mb into about 6mb for one level), but I get a ridiculous amount of artifacts. is there a way which i can decrease the likelihood of artifacts occurring in my bakes, or is this just the nature of the beast?

I am currently in the same situation.
I’m afraid it is the nature of the beast…
However, what you can do, is leave the “compress lightmaps” OFF during baking. Then after baking you can manually change compression and resolution of your lightmaps.
I found that if i do this and set the format of a lightmap to rgb 16bit, quality is ok, but still saves MB’s…
Hope it helps.

Hi there,

as the issue still exists in Unity 2020, I wanted to add another solution to this problem.
As far as I am aware, it appears to me, that the compression System might paint parts of the lightmap plain white /black that are not in use.

I have experienced, that when you are changing your scene a lot, then the compression System still paints parts white that are now covered with your newly added object’s ligtmap coordinates. Therefore you get those horrible artifacts.

Solution:
DISABLING the compression, baking lightmaps and ENABLING it again and BAKING AGAIN solved the problem for me.

I am not sure if I really had to bake the lightmap twice as all my artefacts are gone now. Maybe simply disabling and enabling would have done the job, too.

cheers.