I'm trying to get some more crispy images with more relief and contrasted light.
Definitely impossible using only DL mode 3, so this time I opted for DL mode 4 trying to increase the light by adding emits on the windows. Quite slow but I think it is the only way to get something more realistic from light point of view. Not yet the result I expect but not so far, I'll investigate a bit more.
Render time : about 1h on two gtx580
Postpro : mix with a DL mode 3 render to increase light on some areas and to get more white walls.
I also tried using PMC but after about 2 hours I stoped, too noisy.
More to come ...