Lighting not even across adjacent planar objects

Whenever I have multiple meshes that live on the same plane and they are right next to eachother, the lighting never evenly spreads across the objects after I build the lighting. It is almost finding the average for each object and it looks posterized. Any ideas on why, and how I might fix it?

Hi, this is a very well known problem. Lightmass calculates the lighting per object, as you mentioned already. Because your left wall is closer to the window it will be a bit brighter overall. This isn’t great for Arch Viz but you can easily avoid it by making this wall one mesh and not two.

Hi!

Go with 0.1 indirect lighting level scale and 0.6 with smoothness and those shading differences will disappear!