Artefact on shadow area ?


I am working on personnal project, and have a nice render, except on 2 or 3 areas. I don’t know why.
It’s clean everywhere, except here.

I join 2 screen, you can see where it’s clean, and where it’s weird.

Do you have any idea about this “artefact” ?

You can see my world setting, Reflect capture are 1024, no post process grain, no hdri. Just direction light and skylight with a white cubemap.
Lightmaps are between 512 and 1024 ( 1024 for the wall )
Light quality : production

this problem appeared when I add 4 or 5 spot light…


Someone have an idea ?

I unchecked “compress lightmap”, an “streaming texture”… same result :confused:

sorry to up again, but I’m still in trouble :confused:

Try increasing indirect lighting quality. Also try using the multi-bounce skylight tweak on here (make sure you lower bounces to 10)

If those 2 options don’t work, you might have to try tweaking settings in BaseLightmass.ini

Hey ZacD !

Thanks :slight_smile: I tried to increase indirect lighting, without result.
I tried the multi bounce skylight, and it’s very nice ! Do you know how to set the bounce number ?

Have a nice day,


Second option under lightmass settings, I think yours is currently set to 100.

Hum I don’t understand.

The “multi bound skylight” is same than the “Num indirect light bounces” ??

If it’s same, what is the usefulness of the new lightmass.exe ?

The impact of each bounce drops off pretty quickly. Having the skylight providing more than one bounce makes up for the less number of bounces over all. Try comparing 10 bounces with the modified exe to 100 without it.