Hi,
I have a scene which uses a standard directional light and a standard skylight.
When used with Lumen i get the nice Global Illumination and we get control of Skylight Leaking via a PostProcess which helps with some of the interior lighting.
For some console platforms we have to disable Global Illumination and as a result the Skylight now floods full strength light into the interiors (in the same way as if LightLeaking was set to 1 - even though its set to 0). The buildings double sided walls dont seem to occlude the skylights lighting.
Is this the expected behaviour? If so, is there a work around please? As currently for the skylight strength to be correct for outside, its too bright for inside.
Thanks,
Leon.
Hello,
Skylight Shadowing and Skylight Leaking is a feature of Lumen, so disabling Global Illumination will disable the shadowing, resulting in full skylight leaking.
Two workarounds you could try:
- Use volumes to control the skylight intensity, to reduce it when inside.
- Use local Post-Process Volumes to correct for the extra light via exposure, color grading, Post-Process Materials, or other art-directed methods
Keep in mind that without proper blending, this can lead to lighting pops. It will also affect the entire scene, meaning, looking into a window in either direction will not match what Lumen does.
Please let us know if this helps.
Hi Stephen,
Thanks for getting back to me. I hadn’t appreciated it was a Lumen specific feature.
What does Cast Shadows on the skylights do please? It doesn’t seem to affect anything whether GI is on or off? I cant even see any subtle changes, maybe I’m missing something.
The problem i have is two fold. 1) is supporting the game on low end platforms where Lumen isn’t available and 2) Lumen disables itself when the screen splits for 3 or 4 players. 1 & 2 is ok. This unfortunately means I get a huge difference in lighting as the third and forth players join a game. This is suggesting i should avoid using Lumen at all which is a shame.
I need to fall to a non-Lumen solution to cover all bases. When using exposure I’m finding its counter intuitive to darken an area when you go into a building as normally the exposure brightens it up and then i have to over do the lights. The volumes to control the skylight sounds to me like my only option.
Are these an actual skylight controlling volume or is it just that i need to setup a BP to control these volumes, adjusting the brightness of the skylight when inside. If i do this will it darken it for all players on the other split screens, even the ones outside the room, or is it associated to just the camera/split thats within the volume? ie so for the players outside the room, that aren’t in the the skylight controlling volume, nothing changes?
It feels like all options have potential issues 
Thanks for your help,
Leon.
Hello,
What does Cast Shadows on the skylights do please?
Cast Shadows on a skylight is used for Distance Field Ambient Occlusion and baked lighting. Can you please check whether DFAO is enabled in your case (“r.DistanceFieldAO”)?
When using exposure … as normally the exposure brightens it up
While authoring, you can try setting the viewport to a constant EV in the Viewport toolbar menu.
Are these an actual skylight controlling volume or is it just that i need to setup a BP to control these volumes
They would be a custom volume you would need to create. For an example, you can look at how Post-Process Volumes use a Brush component. Based on your implementation this could be a client-side scalar that is applied to the Skylight.
Please let us know if this helps.
Thats all very helpful thank you. It was really for some official clarity of how its all expected to work and how others work around this, just in case I was missing anything. Thanks again
Hello,
Thank you for the reply.
Can we close your case? You can always re-open it if you need additional information about the same issue.
yes you can close this for now, thank you Stephen