[Request] "Region render" for lightmap calc

[Tim_Hobson]

documentation: CPU Lightmass Global Illumination in Unreal Engine | Unreal Engine 5.3 Documentation

Lightmass emits photons based on the size of the level, so those background meshes will greatly increase the number of photons that need to be emitted, and lighting build times will increase. The Lightmass Importance Volume controls the area that Lightmass emits photons in, allowing you to concentrate it only on the area that needs detailed indirect lighting. Areas outside the importance volume get only one bounce of indirect lighting at a lower quality.

I hope this helps explain it a little better and why you’re seeing lower quality outside of the LMV.