At this point I have tried everything suggested in other threads related to this topic.
I’ve even found a solution when using cascaded shadow maps:
On the directional (sun) light slightly reducing the shadow amount from 1.0 to something like 0.98 fixes this issue immediately.
However, we would like to use Virtual Shadow Maps on highest graphics settings, so this isn’t really a solution for us.
So are there any solutions we could try to make Lumen’s interior lighting less dark?
I’ve attached three screenshots, one shows the interior lit by Lumen, one the Lumen scene and one the interior lit without lumen.
The reason I chose to include the lumen scene is that in other threads the OP often had obvious mistakes in their lumen scene, but I could not find any in ours.
Finally, I’ve attached two screenshots with the same settings but of an exterior view, both with and without Lumen. Here, the exterior scenes look nearly identical!
I hope this helps with showcasing the issue we face with Lumen.
Another good option would be to increase the base color of your materials so that they bounce more light into the room.
More work but it helps to design your levels with larger windows when using Software Lumen, because the global distance field will close them up.
Those are the most natural looking options.
For unnatural looking options; If you don’t care about glossy reflection quality you can use SkyLight Leaking in the post process volume.
If you do then you can use the Albedo Boost in the Post Process Volume, or increase the Indirect Lighting Intensity in your light settings (NOT the Post Process Volume)
I second all of this, although I’ll add you should expect to author lighting (and other content) differently with Lumen/RT.
Real medieval homes were not very bright places, due to having small windows. The human eye will adapt to these conditions (simulated by change the exposure), or if needed they seek additional light. For example poorer homes used cheap lights like tallow soaked rush, while wealthier homes used candles.
This is arguably more of an art problem revealed by tech, than a tech problem. I’d explore how the more realistic lighting might effect the characters and environment of the gameworld.
Ask yourself how the resident of that house would deal with it. Would they care, what kind of lighting do they have access to (cost, resource availability, technological level), etc.
add a bit of skylight. the only source of external light is the lil bit of the directional light coming thru the door and bouncing off the floor. ofc this is not gonna do much. might aswell add a brighter lamp for the chandalier and fireplace. artist direction. not necessarily a technical issue.
First of all thank you very much for all the responses guys!
I’ve tried the suggestions that I had not tried before.
The Albedo / Diffuse Boost in PP volume seems most promising so far.
Although this affects the entire game world, not just interiors, so it’s not directly a solution to the problem at hand. It succeeds in making the lumen shadow results brighter, which is nice.
At the moment I am not looking for an art direction solution yet, that would be the next step.
Right now I’m still trying to figure out if / how much this can be solved on a technical level.
The problem I see is that both without Lumen on, and with the Pathtracer view the scene appears to be brightly lit, as it should be on a sunny day with the lighting settings we chose.
I’ll share two screenshots below of what I mean, the first is with the original settings I used in the screenshots I shared before.
The other is with the lighting adjusted a bit and the settings disabled that we already used to brighten up the Lumen scene.
This second screenshot shows roughly how I would like Lumen to light the scene.
Give the interior its own post process volume? Not like you have to stick with just a global PPV.
Also this situation is pretty much the textbook example of why auto-exposure exists. Any scene with a high dynamic range (such as a mix of interiors/exteriors) is inevitably going to require adjusting the exposure depending on what’s in view to get decent results.
100%. The majority of the time the game camera is meant to either simulate our eyes, or a film camera. Both of those things will adapt their exposure in changing lighting, so we generally should expect to do so in the game camera too.
We are making a Third Person Action RPG so we definitely don’t want to simulate eye adaptation like in a first person perspective game.
In my experience these effects can be quite jarring for the player in a third person game.
My main goal with this thread was to check if an actual solution to the problem that Lumen darkens interior scenes more than it should exists.
At least from the potential fixes proposed in this thread, I wouldn’t call any of them a solution.
So I have since implemented our fallback hotfix to this situation that I decided on a while ago in case no better solution comes up.
We have a custom actor component on the player camera that detects whether it is in an interior space, or outside.
While in interior:
On Low + Medium Global illumination settings we darken the scene by reducing the intensity of the sky light, sun light etc.
On High+ settings with Lumen we do the opposite and brighten the scene by increasing the intensities.
To further enhance this effect we adjust Ambient occlusion strength, local exposure shadows setting, sky light leaking etc. in post processing for each of these two “interior lighting settings”.
This is the best way I have found so far to ensure that the interior scenes are rendered with consistent lighting with and without Lumen.
Of course if somebody has a better solution, I’m all ears!
Increasing the literal brightness of lights is not really any different than increasing the perceived brightness of light due to changes in exposure. You can simply just manually increase the exposure if the character is indoors if you have an aversion to eye adaptation specifically - but despite the name it’s not just for 1st person. A camera has “auto exposure” too, and films shot with cameras will adjust exposure just like our eyes adapt.
It seems to me like you are trying to avoid using the wheel by reinventing the wheel but with extra steps.
That said it is perfectly reasonable to adjust some settings based on context to achieve the desired image result… I just wanted to clarify that there is really no difference between increasing the literal brightness of light vs increasing the perceived brightness of light.
@BananableOffense agreed. even AAA thrid person titles use exposure changes in situations that require it.
the natural way to light up the interiors is just adding more light levels, which op doesn’t wanna do either. so they juggle lumen instead of doing the easy thing. hmm…
It doesn’t. How a scene looks to the viewer is only partly to do with the light, the other part is the exposure.
A candle can look as bright as the sun, and the sun can look as dim as a candle, depending on where you set your exposure. The amount of light they emit is the same regardless, the only difference is how much of it is hitting the sensor: That’s the exposure.
It’s your project, if you don’t want to change the exposure that’s fine. But this is not a problem with Lumen, and refusing to adjust the exposure eliminates easily the most powerful tool you have at your disposal for addressing this issue while still producing a natural looking result. Everything else is just a hack.
As a final word of caution, I leave you with this excerpt from a post by Bart Wronski who worked on God of War in his article about local tonemapping (this feature is called Local Exposure in UE5):
Some artists would desperately suggest “let’s boost the GI!” “let’s boost bounced lighting!” “let’s boost just the ambient/sky lighting intensity!” and sometimes you could get away with that on previous generation of consoles and non-PBR workflows, but in PBR pipeline, it’s almost impossible not to destroy your scene this way. Why? Large family of problems it creates is balance of specular and diffuse lighting.
If you hack just diffuse lighting component (by boosting the diffuse GI), your objects will look chalky or plastic and your metals will be too dark; other objects sometimes glow in the dark. If you boost also indirect speculars, suddenly under some conditions objects will look oily and/or metallic; your mirror-like glossy surfaces will look weird and lose sense of grounding.
Finally, this is not only GI specific, but applies to any hacks in PBR workflow – when you start hacking sun/sky/GI intensities, you lose ability to quickly reason about material responses and the lighting itself and debugging them – as you can’t trust what you see and many factors can be the source of the problem.
