Hey guys. Just experimenting with importing a UE4 4.26 project into UE5 and everything is looking fantastic apart from the shadows. I know this a common issue as I have seen a few posts about it (all of which I am following) but I haven’t yet seen any responses to them.
I have highlighted the worst areas in the scene with a red circle and the blue arrow shows that each wall is its own mesh. (See yellow outline).
I have a PostProcess volume in the scene but whether Enabled or Disabled the shadows are still an issue.
The scene is set up to use Lumen and I have restarted the engine after editing the preferences.
The lighting is using the SkyAtmosphere system and there are no other lights in the scene.
The list of things I have tried is rather extensive, but before I go into listing everything out (and turning this question into a novel!) perhaps someone might be able to point me in the right direction of what I could do to resolve this?
So you just have a SkyAtmosphere and no directional light or local area or point or spot lights in the scene? it looks like you might have a directional.
try it with a directional, SkyAtmosphere, skylight and volumetric clouds.
make sure the skylight is set to realtime and raytraced shadows enabled. make sure everything is movable in the lighting system and not stationary or static. make sure the directional light is set to be the sun and sky light. also, check the mesh distance fields and see if they are detailed enough.
I should have clarified my lighting setup a little clearer, my apologies.
Sorry, when I said I didn’t have any other lights in the scene, I mean’t like spotlights, point lights or rec lights which could have been clashing with the main directional light.
I have also gone through and checked everything is set to moveable and that raytraced shadows are enabled, which they are and unfortunatley there is no difference in the scene.
I’ve also noticed that I am getting splotchy shadows around the scene. The worst is in one of the upstairs rooms where it looks a real mess.
Try turning hardware raytracing off I’ve been fighting shadow artifacts for a few days now and the culprit seems to be the RTX raytracing doesn’t play that nicely yet with Lumen. switching it off and just using lumen seems to solve it… if anyone has any other suggestions the please let me know as well.
This can happen when light has to bounce many times to get to a certain spot or when using emissive surfaces as light. On both cases the amount of rays is limited thus the denoiser can be very visible.
Suggest adding more direct light, bigger windows or secondary light sources to try and hide this.
“Increase the “Final Gather” Setting in your Post Process Volume to get rid of the splotchy GI. 5 works good on my system, moving it to 6 really hits the performance”.
It seemed to make no difference in clearly up the splotchy results with a setting of 5…6…8…12…30…75…or even 100! (pictured)
(The Post Process is definitely enabled as the setting to adjust Final Gather becomes disabled if its not. Ive also tried it on a confined volume and an infinite unbound, and still no difference in the results?).
Next, I went back to the kitchen shot and tried:
“You can try adding a plane or box just above the ceiling and/or enable double sided materials.”
So I tried absolutely blowing out the lighting to see if I could nuke that noise, but even at 80.0 lux, the noise is still there!
As for option 2, unfortunately the design is fixed and I cant make any structural changes to the build.
I think maybe the secondary light might help, (I haven’t tried that yet). I was really trying to find a way to tweak the setings to get a natural response from Lumen without having to help it or fake lighting to get the right result.
(I guess the next question is, are people still using rec lights to help their interior scenes?)
That final gather slider seems to be broken to some folk, probably related to ported projects. It doesn’t do anything for me either, no visual or performance difference no matter if its 0 or 5000 but it does seem to fix it in projects created in ue5
DId you ever solve this? Ive notice the same in that situation with units that are just off the cieling. My read on it is that those sort of areas are only lit by quite a lot of bounce light and so it’s harder to get that smooth quality there.
One solution I found the helped a bit is to use rectangle light in the windows instead of just relying on the sky and sun but that does depend on the window sizes a bit. You could always fake it and add a couple of rectangle light on top of the units just to bounce light up to the cieling