Lighting studies, with some modular level architecture and props thrown in.
Lit in two passes - I lit with "fill" lights first, to make sure the mood was what I wanted and the rooms were lit to the extent I wanted, then the "key" lights made heavy use of LightFunctions to simulate the projections. Shadow-casting and attenuation ranges were kept to minimal values while still enabling me to more-or-less replicate the look and feel of my reference.
The first room has a couple of "rim" static lights to brighten up areas where the other lights weren't reaching, and in cases where increasing bounced lighting would lighten peripheral level architecture too much.
Heavily inspired by Nonotak Studio: