A Digital Manhattan in 'The Avengers'
Jeff White, visual effects supervisor for The Avengers, explains how a digital New York was created for the film in a slideshow on The New York Times.
He says, "One of the real challenges is that you’re somewhat limited in what you can do in New York. The last third of the movie is action-packed and filled with a lot of explosions and there are quite a few restrictions in terms of pyrotechnics and road closures, so to tell the kind of story that Joss Whedon wanted to tell, it eventually became too difficult to try and pull off in New York.”
See it here.