So I finally found some settings that’ll make the Archvis crowd stop complaining about noise under indirect light, especially in reflections. Maybe I’m late to the party here and someone else found this, but here it is:
Default:
r.LumenScene.Radiosity.Temporal.MaxFramesAccumulated 4
r.LumenScene.Radiosity.HemisphereProbeResolution 4
Default (Low) Probe Resolution, Very High Temporal Count:
r.LumenScene.Radiosity.Temporal.MaxFramesAccumulated 32
r.LumenScene.Radiosity.HemisphereProbeResolution 4
High Probe Resolution, Moderate Temporal Count:
r.LumenScene.Radiosity.Temporal.MaxFramesAccumulated 8
r.LumenScene.Radiosity.HemisphereProbeResolution 16
This cost me about 1 ms in editor at native 4k in this test on a 3080. Basically, the quality issue appears to be a combination of trying to get away with both low probe resolution and low temporal accumulation. The sweet spot for quality here seems to be at spatial * temporal = 128
But I’m guessing it’ll vary by scene.
Going too low on temporal, even with very high spatial does not work well because you need enough frames for things to become stable. 4 frames was basically never enough for a temporally stable image.
Ultimately, scaling this up is definitely real time viable so for anyone looking to get cleaner reflections, here ya go.