I haven’t been able to find threads about this specific issue, but from time to time, bright colored flashes (often red, green, blue, or a mix) appear in the volumetric fog. GI doesn’t seem to be impacted, but I haven’t noticed this bug when disabling Lumen. It has unfortunately been really hard to reproduce consistently. These flashes appear both in editor and in shipping builds.
I’m using SWRT Lumen and reflections, no Mega Lights, no VSM, no Nanite.
I captured one instance and made a GIF. I’m only using spots and point lights, and there are no emissive materials contributing to Lumen near the artefact (I’m using the node “Ray Tracing Quality Switch Replace = 0” in most materials). If anyone has any idea what it is and how to fix it, it’d be awesome!
Thanks for the reply, but setting TemporalReprojection to 0 made the fog super stuttery (it’s very dense in my scene). The solution and tips suggested are aimed at virtual production and sacrifice performance for visual quality, while I’m working on a game, so I can’t afford to tank performance
Though I did have the smearing issue they’re talking about in this post. Setting r.VolumetricFog.HistoryWeight to a lower value helped a lot! I found this Steam discussion, which also helped.
