(New Lumen in UE5) Why is the ceiling of my parking garage so dark?

[PerCat]

Hello all! I am trying to put some basic square lights in my parking garage for a cityscape area type thing.

But no matter what I do I can’t seem to figure out how to make my ceiling light up properly. They are rectangular lights pointing downwards so they won’t light up very much anyways.

But is there a way for light bounce to it? Maybe make another rectangle light facing towards the ceiling?

These are dynamic lights, I do not have any other lighting or post processing effects as of now.

I want the dark areas to stay dark but I want the parts with lights to actually look how lights would look in this scene, lights usually light all around it.

I don’t really want auto exposure cause I absolutely despise how it looks when you go from exteriors to interiors or even dark to light areas.

What I got

Vs

What I want

Any help or tips appreciated, thank you!

[Suthriel]

Your rect light is pretty weak compared to the lights in your example photo. How does it look with increased strenght?

However, you probably will run into trouble with so many small lights, if they are so close together. I kinda rebuilt your scene and placed some rect lights, and almost all got a crossed out icon, because too many lights in a certain radius (they still enlightened the scene way better than your test, so not sure, what this icon means, but it def have a meaning ^.^)

So maybe retry it with fewer but bigger lights, or throw in some cubes with emissive materials.
Got pretty good results with that, but again, Lumen requires objects with emissive materials to be above a certain minimum size, or they will be ignored by Lumen, and will only work for the fallback screen space stuff.

Test video, with just emissive blocks, all rect lights were disabled (also notice, how far away blocks get ignored too and light-wise pop into existence, if you get closer):

UE5 - Lumen Emissive Object Size

This is a standard Lumen scene, no raytracing involved.

Edit: Just for completion, i did another test, where i positioned rect lights right below each emissive mesh, and made them as big as the cubes are. then just some balancing between their brightness and the intensity of the emissive material, and you get really nice looking results
The rect lights give you all the sharper shadows, that Lumen fail to create with emissive materials, while also hiding that popping in effect, if an emissive block is too far away.
On the other hand, the emissive blocks cover some stuff in close ups, where the rect lights fail, most noticeable at the light at the ramp.

So i would say, with a combination of those both (fewer and bigger lights overall), you should get really good results.
Also, that crossed out icon didn´t matter and vanished, once i set all rect lights to moveable. It seems to be an indicator for light baking and static lights, which we don´t use with Lumen.

UE5 - Rect Light and Emissive Mesh

Have a hopefully enlightened day ^.^

[bjgil2]

In one of the Valley of the Ancients videos the devs mentioned that the albedo of the surfaces dramatically affects how much bounce light is contributed to Lumen. Your walls are much darker than the concrete in your reference picture so try applying a lighter grey colour and see if it makes a difference.

[FrankieV]

not working with 5 yet but looks like an indirect lighting intensity is not high enough

- YouTube

[PerCat]

This is a really good reply and I thank you, but my I think I figured out what my issues stem from.

So your lights jut out from the ceiling which makes the emissive material and light, light up the ceiling by itself… Is there a way to accomplish something similar without making my lights jut out? I’m trying to make them flush with my ceiling but can’t quite figure it out, bumping it up to even ridiculous strengths(50k+) does nothing to help.

And my lights are already quite big 100x100 so I don’t want them even bigger.

I ended up using point lights instead of rectangle lights unfortunately, they don’t look as good when casted into the world but I can’t make the lights get the ceiling like I want it and be flush.

Thank you for your reply and time. Much appreciated.

[Suthriel]

@PerCat

Is there a way to accomplish something similar without making my lights jut out? I’m trying to make them flush with my ceiling but can’t quite figure it out, bumping it up to even ridiculous strengths(50k+) does nothing to help.

I ended up using point lights instead of rectangle lights unfortunately,

I tested it with almost hidden lights, and the scene got really dark, if just the emissive material was active. In this case, the additional rect lights below the emissive blocks were absolutely necessary to compensate for all the missing emissive surface.

So with flush lights, at least for now, you seem to really need an additional light source below them/below the ceiling, that can send out light in all directions, unless you have really big emissive surfaces.

First image is emissive only, second is emissive and rect light (they moved up to, the distance between the emissive blocks and rect lights is still the same as in the video), third and fourth is rect lights only. Fourth only to show the rect light position, and that they have flat and spread out barn doors (they are at 90 degrees).

[PerCat]

Thank you, I’ll give this a try