These have been produced by teams from De Monfort University - formerly Leicester School of Art and then Leicester Polytechnic - for a British Library competition called 'Off the Map'; and they are built, literally, from contemporary maps. First, here's the entry by a team calling themselves Pudding Lane Productions:
Next, this one from the Optimistic Pessimists:
This is cleaner and crisper, not quite so realistic to my eye; but the flow from exterior to interior, and the interior detailing, is, again, inspirational.
And finally, the Triumphant Goat entry, which, frankly, I find most inspirational of the lot:
The actual competition was won by the first of these - Pudding Lane Productions - but they're all very good, especially in view of the quite small teams involved.
All of these models were built using the CryEngine, developed for the Crysis video game; it's a free download, although it's closed source and you have to pay royalties if you use it for any commercial purpose. As far as I can see, none of the teams have made their work available for download - which is understandable but disappointing. It would have been nice to be able to learn from them.
These maps, of course, represent a real city, and there are reasons why a video game environment should not too closely model a real city. It's awkward to navigate very narrow alleys in a video game; it's easier, in a video game environment, to get disoriented than in a real environment - because you have, in fact, many fewer spacial orientation cues.
So what I'm trying to build is algorithms to create environments which have convincing verisimilitude without being real reproductions of real world environments - but nevertheless these environments inspire me.