My third attempt at making realistic clouds, this time their less raggedy and more bumpy.
The clouds interacting with the buildings turned out surprisingly well, the only (easily fixable) problem was very minor and involved clouds reflected in the windows (how Blender treats reflected rays going through z-transparent meshes), not the clouds themselves (which I found was probably me having the reydepth too low). There were also some problems with sky showing through at the building edges but that was greatly reduced in the Blender compositor…
You’ll need to see the full size image to see all the detail. But I think this turned out really well, and this time it only took 11 hours and 30 minutes to render.