No problem, I was with stuff too. Been out of the loop for a few days.
Tracing is scene-independent, so we are looking at voxelization performance. On the memory size, something like 512512512 voxels is about the for a 2 GB card. Not saying you can’t push it higher, actually with that it’s just 16 + 64 mb of memory used for the voxels, but it starts to go down after that, and 512^3 it’s quite a lot in practice. Let’s do some math ( and assume you are centering the grid on the player and making it move with him). Also, do correct me if I make some screw-up.
You have 512512512 = 134217728 voxels. Let’s take a height of 25 m, and a desired voxel size of 0.5 m. With that, we have 134217728/50 = 2684354 voxels per height plane. We then do the square root of 2684354 and get 1638 voxels per side. Multiplying by the voxel size, we get 820 m.
So you could cover a 0.8 - 1.5 km^2 area with a 25 mt height without much problem. Consider that it’s quite unlikely for the character to see 800 at the same time.
After , it depends on the scene complexity. I use the last LOD for voxelization, so if you have some aggressive lod for the last one it should help. Not really sure how will run, but it should be doable.
I do think it will (or at least should) be faster to use HFGI ( no DFGI ) for the terrains instead of AHR, and use AHR for all the others. I mean, not voxelizing the terrain. Haven’t tried . Also, I think that currently terrains aren’t working, like, they don’t get voxelized, should look into it, but like I said, HFGI is probably better for that.