Hello and Happy Holidays!
Using Unreal Engine 5.5. I’m having a really hard time trying to figure out why a Directional Light is shining through objects/meshes. What setting am I missing to prevent this? Here is an example of 6 cubes creating a closed space:
Outside
Inside
I’ve spent hours searching for a setting and have tried several that were suggested and I just cannot get a 100% dark interior that I can add point lights to.
Hey there @Krotus! Welcome back to the community! Generally there’s a couple measures to help with light bleeding that can mitigate it without extra geometry, but in many cases with large rooms you may want to work out the logistics of disabling the light when underground and only reenabling it when it should be visible again. Using that technique and extra blocking volumes on problematic areas can also help.
Newbie here. But encountered a similar problem. Discovered it was because auto exposure was on with no post effects to counter it. Is that possibly it?
Thanks, but no, that doesn’t appear to be the issue.
Thanks. I had kind of started thinking that turning off the directional light when underground would be the easiest solution, I just wanted to check here first for any setting(s) I may be missing.
The skylight will affect everything unless you’re using something more complete like Lumen or baked lighting. There’s also DFAO which will darken larger areas occluding the skylight, but it’s a more rough approximation.
So your options are:
Use Lumen
Use baked lighting
Turn off the skylight if in occluded areas (or change it to a different HDRI that better represents the scene)
Use DFAO and deal with some of the effect
Use something else for lighting
The engine doesnt have a proper Runtime GI.
Normally, you put “stuff” in the doorways that didables or reduces the skylight settings when yku enter.
Also, a properly made Manifold model will prevent bleeding much better than adjacent or even overlapping objects.
Thats generally why in Modular Kits you make Corners that can be used directly as corners.
In ue4.x you can sort of levarage distance fields to somewaht adjust the bleed by way of forcing more shadow - which somewhat also helps get the room darker when you disable or control auto-exposure.
Using Baked Light mentioned above would fail btw.
As I said, you can’t stack random objects and expect the lightmap to work right after bake.
You need precise models with correct light UVs and honestly, to enclose a room for a light build- not only would the model need to be merged (which is just best practice), but you would probably also have to give it a double shell made of 1m thick engine blocks in order to prevent any light from baking in the exterior of the walls;
Thanks to the total mess that the engine makes of shaders, any light hitting the mesh anywhere will results in light bleeding thorugh to the other side of a double sided manifold mesh…
Additionally, the shadowing artifact you see at the junctures is more a result of TAA than the engine’s light of DFAO/light calcs.
Youd get almost no artefacts in forwardshading mode. Which is something to at least consider…
