NvRTX for UE 5.2 - Raytraced Volumetric Fog not working

[eidolon64]

I just built the new 5.2 version of the NvRTX branch and I think there is something off with the Raytraced Volumetric Fog.

I added a spot light with volumetric shadows enabled and volumetric fog in the scene.

This is what it looks like when I set the Cvar r.RayTracing.VolumeFogMode to 2:

You can see that the volumetric shadow cast by the sphere is not aligned with the light and there is a dark artifact around the sphere.
Additionally, setting the Cvar to 1 doesn’t have any effect.

I think this is a regression compared with previous versions of NvRTX, where the RT volumetric shadows with VolumeFogMode set to 2 matched the raster shadows.

[eidolon64]

For reference, this is what the scene looks like with raster shadows (the “correct” version). See how the volumetric shadow cast by the sphere matches the direction and falloff of the spotlight

[MarkusHoHo]

Hi there @eidolon64, welcome to the NVIDIA developer forums!

Thank you for bringing this up!

I forwarded to the team and will hopefully get some feedback soon.

Thanks!

[MarkusHoHo]

Hi again @eidolon64, good news.

Issue reproduced, identified and fixed. It might take a couple of cycles until it passes our QA, but it should come to github soon.

Thanks!

[eidolon64]

Wonderful, thank you for the super quick fix!

[ehart]

Just to close the loop, The hotfix was pushed to github today.

[eidolon64]

Awesome, I just tested it and it works great, thank you!