My new Olympus TG-850 has this diorama mode as one of its "art filters". So I am basically shooting the scene and the camera is doing all the work for me. The key to a realistic fake City picture is having a high view point of a street view with people and cars, ideally not moving fast that they are blurred. No fake city model ever has fast moving static cars, got it??!!
Here are some of my attempts.
Just for fun I wondered through the city mall to see if that's viable too. One thing I lacked in both scene's was people. I managed to convince 3 'random' persons to wander through my mall scene though!!!