r.RayTracing.VolumeFogMode=1 does not work in NVRTX5.1

r.RayTracing.VolumeFogMode=1 does not work in NVRTX5.1
Volumetric fog projection cannot be supported when ray traced shadows are enabled.

Don’t you guys have this problem?

Hi there @Bio_Weapon_Re and welcome to the NVIDIA developer forums!

Your Google Drive link is not accessible, you probably need to adjust your sharing settings.

In general, could you tell us a bit more about your setup? Like

  • UE version you are using
  • GPU Driver version
  • NVRTX version and wether you use the plugin or a Github clone of the NVIDIA branch

That might help narrow down whether this is a regression or expected behaviour.


RT shadow cannot cast volumetric fog shadows.
.RayTracing.VolumeFogMode=1 does not work in NVRTX5.1
The UE version I use is NVRTX5.1

GPU Driver version 527.56
My gpu is rtx4090

Thank you for the quick response!

Looks very cool by the way.

Did this work correctly with an older version of NvRTX?
Can you ideally share a shot of the same scene with the intended effect?

I don’t have the old NVRTX5.0 anymore. I can only use virtual shadow maps for comparison.

UE5.1 Virtual shadow maps

NVRTX5.1 RT Shadow r.RayTracing.VolumeFogMode=1

Thanks! I’ll pass it on.

But did it work correctly with previous versions of NvRTX?

This is NvRTX_Caustics-4.27 open r.RayTracing.VolumeFogMode=1

This is NvRTX5.1 open r.RayTracing.VolumeFogMode=1
doesn’t work at all

Hello, I think you can use mode 2 instead, r.RayTracing.VolumeFogMode=2

Hello, are you using the latest nvrtx5.1?

I entered r.RayTracing.VolumeFogMode=2 and there is still no change

NvRTX Caustics 5.1 still does not support r.RayTracing.VolumeFogMode=1.
Ray-traced shadows do not support volumetric fog projection, and Tyndall effects cannot be produced.

Use volumefogmode=2, sorry about the confusion here. Jacky Wang is correct. =)