How to light many rooms without performance issues?

[BrokenBluescreen]

Hey, I am having a problem of inexperience with unreal engine, following situation: I have a building in a level with like 50 rooms, and every room would need lighting, meaning I would have at least 50 static lights in my scene. I am using unreal engine 5.3, and I realised that I need a bit more optimization, as in my level, which so far is just the enviroment build with no blueprints whatsoever, on a device tested had like 40 fps, which is not acceptable yet. I am now currently working on redoing whatever mess I had created when placing the lights for the first time.
Now the following problem:

To have my room look good lighting whise, like this, I have to increase the attentuation radius to around 800, which then makes the room look good, but it causes the lights radius to go over the walls into the next room, and well, there they intersect and then cause this

This is a screenshot from the same room, but as you can see in lighting complexity mode. Now, I already dont have much in my scene, around 4000 actors for a whole building with 50 rooms, and this is already running at 40 fps on target hardware, meaning I am trying to optimize this as much as possible.
But to have the room look good lighting whise, I need to have the radius increased which then causes this overlap, meaning performance issues.
Does someone have an idea how this could maybe be solved?

[glitchered]

in the advanced light options you could disable the square falloff and dial in the falloff exponent. that gives you shorter attenuation range while maintaining brightness. it’s a tradeoff between performance and realism.

or…

you gotta limit how far lights are rendered if they are not “in camera” or not on the same floor or occluded somehow. so… only a part of the level is actually lit.

or…

if it’s static scenery, you could bake it using lightmass. it will take time to optimize but does not have overlap at all. you only require a small amount of attenuation to cast dynamic shadows properly.

dev note: i don’t remember if 5.4 will have stochastic lighting/shadows already, but 5.5 is defo coming later that could increase performance for this localised lighting scenario. hmmhmm

[EliasWick]

Rect lights are quite expensive to use. Cheapest one to use is a spot light. You should be fine to have 50 rooms with lights in them however. If the layout is setup so that you allow culling between the rooms to work, it shouldn’t be too expensive.

Also, combine assets into Packed Level Actors.