This article describes some workarounds/fixes to temporal reprojection issues encountered when using volumetric fog with UE5’s Lumen lighting system, including artifacts that can appear during object or camera animation, particularly in shaded areas.
https://dev.epicgames.com/community/learning/tutorials/6dJK/unreal-engine-lumen-volumetric-fog-temporal-reprojection-issue-workaround-icvr-lightfall
Still not fixed in 5.5. I haven’t found a single workaround that’s worth it so far, been struggling with this issue in cinematics time and time again. It’s extremely frustrating.
Hi there! The rendering algorithm was modified. The key change was the addition of a tracing system to Lumen, which is very similar to ray tracing—in fact, it’s an RT algorithm. They might need to enable Hardware Ray Tracing, though this option is only available for RT-compatible GPUs. Additionally, the tracing option for Lumen GI should be turned on.