It's actually (supposedly) dusk. This project was done quite some time back. The design had been finalized, and we needed a "hero" shot that would show the buildings uniqueness in some way. I guess the Architect knew as well that the design was not much special from any other building, except that it had these "special" windows. So to emphasize on these, was to have it rendered as a night shot. Of course, the tricky part was to show the building's form as well, and as requested by the developer.
So to create the illusion of a night shot, 3d omni lights were thrown into the interior scene, while maintaining a considerable amount of GI to light the exterior. An overall grading of bluish tone and colour adjustment was done as to get the look i perceived was nice. To further enhance the effect, I had to pick a relatively complimenting sky and background as well.
Modeled with 3D Max 7.0
Rendered with Vray
Post-Processed in Photoshop CS