Details:
18 hours on Mac G4 933 1gig RAM
Settings: Quality, Detail, Variability = high
3 bounces
rpict -vf sponza.vp -x 3072 -y 3072 -pa 0.000 -ps 3 -pt .04 -dp 4096 -ar 91 -ms 0.25 -ds .2 -dt .05 -dc .75 -dr 3 -sj 1 -st .01 -ab 3 -af sponza.amb -aa .08 -ad 1024 -as 512 -av 0.5 0.5 0.5 -lr 12 -lw .0005