The final film story that the city built for wasn't ready till well into the production of the film. The story and the 3D modeled city were being designed and growing together but the world art had about a 2 month head start. My plan to try and deal with this was to create city with modular parts and textures. Textures for nice buildings in the rich area with more grungy textures in the lower city being applied to the same geometry. Then to have modular parts such as chimneys, stairs and walls that could be added onto buildings to create a more diverse city.
The end result of this was after the shots and angles for the film were finalized I got to have fun playing in a dollhouse kind of situation. I was placing stairs here and chimneys there moving buildings close together to create wider or more narrow streets based on my imagined history of the city. I spent about three weeks on this part of the production and as always I wish there was more time but that's life.