How can I fix this issue after building light?

[ZulCul]

So I have this issue

As you can see there a noticeable difference in lighting between this two meshes. I use RectLight as lighting source. Mesh has 3 uv channels, so unreal created a fourth one

[Arkiras]

This is variance between individual mesh instances. Lightmass processes each mesh on a separate thread, but they don’t know what the other threads are doing so its possible to get discontinuities between the meshes.

There are two ways to deal with this:

1. Merge the actors into a single mesh so that you can keep seams where they arent noticeable
2. Use higher quality lightmass settings

Here’s a comparison of different settings in one of my scenes, and how they affect build times on my 3900x:

These settings are for my particular scene, your scene may require even higher quality settings. Mostly that means lower the static level lighting scale, and increasing the indirect lighting quality. Again though as you can see, this has a significant impact on lighting build times, so don’t go overboard. If you need it to be perfect, merge the meshes instead.

[ZulCul]

thanks a lot!