How to apply ambient lighting in cave environment


I am curious as to how you guys go about illuminating a cave or similar indoor environment in a open world map that includes sky lights and the like. Currently I am not able to get light to fill my cave through holes in the cave. What settings or volumes would help to provide light from the outside to fill my cave too? I’d like to use the directional light as much as possible.

Here is my current setup:

As you can see, there doesn’t seem to be any light bounces at all, helping to light the cave. (also the exp fog looks odd)



Directional Light:


Post Process 1:

Post Process 2:

Lightmass Importance:

im no lighting expert, but think there needs to be a light near the reflection sphere for it to really be utilized. you can also add a skylight to help simulate inside light and turn it down really low. also, adding ambient occlusion maps to the materials on your floors and walls will help make them more visible in the dark.

@ViceVersa There is a hole in the cave right near the first capture, i have two more captures down a small ways near other holes. I added another screenshot to show this. The light does not directly fall on the captures though.

Adding a skylight in the cave works, but the light looks faked and it affects the entire world. That makes everything brighter which id like to avoid if possible. Lastly, these are assets i migrated from example content and sadly there are no AO maps for the cave walls and the floor. I am too new to know how to create those on my own at the moment. Thanks for the input so far!


Well your skylight is movable so you won’t get any bake information from that! …are you trying dynamic lighting?
I don’t really see any of your settings… but if you have enough openings for the light then you could bake your cave! With higher bounce settings (5?) on static/stationary lights…
There is a fake ambient lighting… with a single point light set it not to cast shadows and play with the inverse squared falloff settings! It will fill your whole scene with fake light…

Good luck!

@Makigirl I would like to try and keep the lighting dynamic. I’m going for a day night cycled , open world. So during the day I’d like the cave to be lit from the holes, then at night be dark. How, at a high level, can I bake just the cave with a move able skylight?

I can post my settings for everything tomorrow to help you guys /gals out.

Oh I see! :slight_smile: I can’t help you with dynamic lighting sorry! :S
…maybe you could bake your “ambient light” (which you would always have in the cave) and add the main dynamic lighting to it… I don’t know if there’s a point! :wink:
…you could still try the point light with inverse falloff and not casting shadows… it would fill up your whole scene… or maybe add a really small emissive to your cave material…

Good luck! :slight_smile:

@Makigirl Baking the lighting first then changing the directional light to moveable actually did work somewhat. There are spots where it’s clear a light was shining down into the cave, even at night. Is there a way to keep the bake for only the cave? I don’t want to lose the light baking due to the moving sun light. This is a decent workaround for the time being. I can also try faking the lighting with a spot light like you and Vice suggested. Take a peek:

Looks cool! :slight_smile:
Maybe the “infinite” light will do the job! That would be the easiest! :wink: :smiley: …but fake! :wink:
Maybe you could bake the “ambient light” to the cave… the minimal light you want to have evening time… With a skylight… and your sun can be movable for the extra light… maybe you can tweak the fog too to get more out of it…
I’m just guessing! :wink: :smiley: