4.22 RTX skylights with other lights ray tracing cause edge flicker in sequence renders

Development Rendering
1

so I have this issues where if I have a skylight in a scene (both on or off for raytracing) and another light is on, directional / rect / point with ratracing on
it’ll cause these flickers on the edge when I render a sequencer sequence
anyone know what causes this?

if the renderer were to pause for a bit before each frame capture, the effect would be off, but I’m not sure of a quick fix for that

here’s a link with an animated gif with the issue

2

I think that’s the denoiser at work.

3

thanks for the reply
hmm… I’ll have to fiddle with console settings to test it out later when i have time to see if that’s really the case

4

These are undersampling artifacts that manifest as fireflies and cause issues during denoising. The same denoiser is used for SkyLight as for GlobalIllumination passes. Your comment regarding inclusion of other lights suggests this is something related to GI rather than related to SkyLight. Can you confirm this is the case?

TAA increases convergence rate as time goes on and will also suppress the fireflies. You should be able to accomplish similar goals by increasing the samples-per-pixel at the cost of interactivity. This may be fine if you are working with a sequencer burnout.

5

even upping the samples on the lights or the raytrace GI, it’s still there, and even as the time goes on for the TAA to converge during renders,
the GI if turned off the sparkles still show up,
only if i turn off the skylight does the sparkles turn off, so for a workaround I could just use area lights instead of skylights

I still haven’t tested if it’s just a denoiser issue though

6

Strange, looking at it, that doesn’t look like noise or firefly problems. I’m not sure what it is…

7

Thanks for the information. I’ll be taking a look soon.

8

cool thanks, it seems the issue doesnt show up on really big scenes ( like battling space ships)
only smaller ones like people scale rooms