Mantra ~ 10 min, Arnold ~ 2 min, Redshift ~ 1 min
Mantra ~ 11 min, Arnold ~ 4 min, Redshift ~ 4 min
Mantra ~ 8 min, Arnold ~ 1 min, Redshift ~ 2 min
Mantra (with GGX) ~ 13 min, Mantra ~ 8 min, Arnold ~ 9 min, Redshift ~ 1 min
Mantra ~ 16 min, Arnold ~ 3 min
4 spp (~ 10.3 M points), 3 spp (~ 5.8 M points), 2 spp (~ 2.5 M points), 1.5 spp (~ 1.5 M points)
Mantra ~ 3 min, Arnold ~ 1 min (particles as discs with correct normals), Arnold (using instancing, too slow), Redshift ~ 3 min (as spheres - incorrect speculars, instancing not possible because of VRAM)
Grid volume (~ 800MB, 272M voxels) - 3:30s, frustum volume 1.0 z (~ 800MB, 272M voxels) - 5:20s, frustum volume 0.75 z (~ 600MB, 204M voxels) - 5:21s, frustum volume 0.5 z (~ 400MB, 136M voxels) - 5:27s, frustum volume 0.25 z (~ 200MB, 68M voxels) - 5:42s
1.0 z means scaling of resolution along Z axis (inside of the image)