Just started work on an environment based on this concept. Going to be focused on improving my texture work and producing as much of the art work my self as possible. I discovered something I maybe should have a year or two ago, that I would much rather be an environment artist and make interesting worlds and game art rather than level design. So Recently started working on 3D modeling again and I am slowly picking it up again.

Anyway got the first screenshot below. All the main stuff blocked out so far, going to see if those main walls can remain BSP and if I good texture + normal will be enough. Then break the massive space up with thin supports you can see in the concept. Also the concept is a bit apocalyptic I am going for a more Fantasy, shadow of the colossus type theme. So the modern vents you can see along the bottom of the walls will be of a different nature and purpose.