I noted down how to get the walls right ( because I could never remember )
– Joining walls
Do you have a importance volume around everything?
In the lightmass settings indirect lighting scale to 0.1-0.15 and 0.6 for smoothness.
– Moveable objects
Lowering the Volumetric Lightmap Detail Cell size under lightmass settings.
The default is 200 ( which is in centimeters ), so with that you get lighting information on movable objects only every 2 meters!
If you go low enough, you’ll have the same quality lighting on everything, including the movable objects too.
I was quoting from @anonymous_user_f26c856c1 there - 