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Understanding Skylights

I am a little confused as to how the skylights work. I have all of my lighting in my scene set up as static, except for my skylight up until now. If I set my skylight to Movable, it fills my scene with a little light, so anywhere I haven’t placed lights, it at least gives it a little bit of ambient light. But if I change it to Static, those areas are now very dark. So basically, when set to Static, it doesn’t really infill dark areas with any ambient light. What causes it to act differently when in Static or Movable? Can I set it Static but still have it infill with some ambient light? Or am I going about that the wrong way and there is a better way?

Have you rebuilt your lighting once you set it to static?

Yes I have. The first “dark” image is right after rebuilding.

Okay, just checking…

I’m no lighting expert and normally use dynamic lighting for everything. However, if you want to inject some extra ambient light into that scene I’d add a lightmass importance volume into your scene (if you don’t already have one) and increase the number of bounces in your lightmass settings.

A movable skylight won’t cast shadows, unless you’re using DFAO (which might look bad indoors like that). If you want the skylight to be static and still shine light inside the building, the skylight needs to not cast shadows (these are calculated when you build the lighting). I believe there is a checkbox called “cast shadows” or something like that in your skylight’s properties. If you uncheck that, it should light up the inside of the building.

EDIT:
Let me add that if you’re going for a realistic look, I would set your skylight and sun to “stationary” rather than movable or static. You can brighten the interior of your building in a variety of ways that won’t have the visual defects caused by a non-shadowing static skylight.

Oh ok. I will try to use both of your tips. I have been trying to understand how to light my interior scenes better, because up until now my lighting has been pretty awful. I appreciate all of the suggestions.

I’d recommend downloading Koola’s lighting study for free: Lightroom: Interior Day Light in Architectural Visualization - UE Marketplace

This way you can see how some of the techniques are done.

There are ceiling lights there, why don’t you just put some static spot lights under each of them? You could even place one spot and one low intensity point light under each of them.

In games people really try to stay away from skylights as they make everything look flat if the intensity is more than 1. In an office like this natural light won’t get all the way to where you took the screenshot from. Skylights are supposed to lighten up the entire scene a bit so you don’t have spots that are pitch black, which would be unrealistic. But they were never meant to lighten up the entire scene. I know many people think differently here but that’s how skylights are used in games and this is a games engine after all.