The making-process consisted of making quite quick and basic render and doing all the rest in Photoshop as a part of post-process (#doitinPOST). You are welcome to read a break-down article about it at http://www.learnarchviz.com/#!PHOTOSHOP-BREAKDOWN-Modern-Office-Building/c8sb/56c2573f0cf2fe0269b1c308.
