Having trouble with Heightfog and the Path Tracer, and could use some help

[Black_Howling (Lucent_Light)]

I’m working on a cinematic in UE 5.2, and the issue I’m having is that the heightfog becomes drastically reduced when using the path tracer renderer. The image shows a comparison between the deferred renderer and PT.

I’ve tried cranking up the fog density, and adjusting where the widget is in world space, but it’s still not dense enough. It’s there, but I can’t seem to get it to match the deferred renderer. Any ideas on how I can get the fog to match while using PT?

Also, does anyone know how to get rid of the harsh black space? I have nothing there, and tried adjusting the ground radius in the Sky Atmo, but it’s still there. I’m using a mirrored skybox, so there should be info there, but something is blocking it.

[Carlos.Cristerna]

@Black_Howling I tried to reproduce your scene and I think there are 2 things happening here.

1. The harsh horizontal line and the black color at the bottom is the “Lower Hemisphere Color” that does not render in Raster but apparently it does in PT
   

   
   
   See below comparison Raster v PT
   
   
   
   Just turn that off in the sky light and it should render the bottom half of your sphere/cubemap
   
   

2. I was having the same issue you were having when the sphere with my background map was “too small” (50 units)
   

   
   
   The solution I found worked for me was to scale the sphere much bigger (5000 units) you should play with this number, I went super high just as a test but it worked
   
   

Last but not least. I was using only a Skylight that is set to Movable with the below modified

Exponential Height fog with Volumetric fog checked only, you should play with the Fog inscattering color if you want something different for your art direction

And here is the graph for the skymap that I mapped to the sphere which the skylight was capturing to light the scene as it was marked “is sky”

Hope this helps

CC

[Black_Howling (Lucent_Light)]

Thank you Carlos, this helps a great deal! Disabling the lower hemisphere also allowed the heightfog to be tuned to work better with PT.

Thanks again for taking the time to respond to this thread!