I had a second serious try with the Blender to Octane integrated plugin, this time in an interior environment.
For this exercise I mainly focused on the lighting, playing with emitter planes behind the windows to increase the light entering in the room. I also avoid the usual mix of hdr and sun renders to get the result in one single pass.
I mainly used direct lighting diffuse and a bit of pathtracing, render time was relatively fast, about 30min to 1h in a quite small res of 1200x900 on two gtx580.
All the images were post processed mainly to get a better contrast. As usual everything was modeled with Blender.