So i knew the rooftop had to be situated in New York but still needed to think about the layout, who would use it, what condition would it be in. To get ideas i began browsing the net and using Google Maps over New York to get a good idea of the average rooftop design.
A smart thing to do would be to look around existing game levels because the idea was going to be used for a in game shooter. I had a look at multi player levels because these would need the most diverse and interesting cover and structure, essentially being an arena it would be intreresting from wherever you were on the level.
In the brief our tri count was heigh enough for us to get creative but the texture budget was going to be a challenge. This really limited me to what i could have in the way of unique 'hero' assets but was something i could work with easily and was happy to accept the challenge.
After exproring plently of images of high rise buildings and rooftop gardens i settled on an industrial style building, not the highest but high none the less. And possibly with a rooftop appartment that the player could look down into giving it an edge on most basic rooftops.