I’ve encountered an issue in my 3rd person game project in UE5 where a shadow trail appears behind my character whenever it moves in front of a flashlight source I added.
I’ve experimented with various configurations related to lighting and shadows but haven’t been able to resolve the issue. I’m using a movable spotlight for the flashlight with a high intensity and 0 volumetric scattering intensity.
Has anyone experienced something similar or knows what might be causing this shadow trail effect? I’m looking for insights on what this trail is called and how I might gain control over it to either reduce its intensity or eliminate it altogether.
I’ve attached a video of this happening. Any advice or suggestions on settings to check or adjust would be greatly appreciated!
I believe I’m having a similar issue when my metahuman’s right hand moves too closely to the mesh over him.
I believe it has something to do with how it’s colliding with the mesh and not anything with shadows. But I’ve tried increasing the mesh bounds and even disabling shadows in the level outliner, but nothing works. It might also have to do with volumetric shadow mapping, since I see the effect to a greater degree when applying those viewing filters.
that is lumen’s temporal filter. “normal” artefact when you have very dark and very light spots changing quickly. also you should be careful with small emissive materials. the noise isn’t really good.
While the artifacts look very similar, I believe we’re facing different issues. Since mine only happens when moving in front of the light source.
Also, when I set the visibility of that very bright flashlight to false (And increase the sky light), the trail is no longer visible either. So I highly doubt that the issue that I am encountering is related to the meshes themselves.
Yours, on the other hand, given the lighting circumstances, seems like might have a different cause.
Thanks for pointing out the issue with Lumen’s temporal filter. I understand it’s causing the shadow trail, but I’m having trouble finding more details on adjusting it. Any suggestions on tweaking this or potential oversights with my flashlight setup would be great.
Also, thanks for the bonus tip about small emissive materials. Regarding the ‘noise’ you mentioned, can you point out where exactly it is and how do you think it can be avoided?
unfortunately that’s not adjustable. i checked a bunch of cvars the other day. but you can’t get rid of it, really. harsh lighting and gi changes aren’t that great.
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