Increasing the voxel grid dencity for Light Propagation Volumes

Development Rendering
1

I never know what to write when I’ve written all I would in the title.

I know LPVs are experimental tech with missing features and bugs here and there but I would like to still use them despite all of their drawbacks. ((I just really hate making Shadow map UVs))

Anyhow, I have a really fast CPU and GPU and I would like to play with higher densities for the LPV voxel grid.I have tried the Size property but that just controls the size and not density. I would like a modest size to fill a room but also have a higher density to lit smaller details. Is that exposed as a variable or setting somewhere? Or would I have to go to the source code to increase it?

2

You can’t adjust the number of voxels currently.

3

If you haven’t already, you can experiment with these CVars:


r.LPV.RSMResolution=1024
r.LPV.NumPropagationSteps=4

I didn’t end up being super happy with the performance cost of these vs. what they actually added, but your mileage may vary?

That said, I still use LPVs in my scene and am, overall, happy-ish with them.

This may elucidate their purpose:
https://answers.unrealengine.com/questions/307258/light-propagation-volume-distance-and-fade-inout.html

4

Heh thanks for the answers, I am not entirely sure what RSMResolution does, it actually seems to break my lighting allowing the skylight to shine though but I am sure that’s just a matter of settings. At least I now know where to look for LPV Cvars. Thanks!