As Mark Ruffalo noted, it used to be that all of the work would have to be done away from the normal set in a specially designed volume — an area where the necessary photography could be done.
Thanks to huge advances, however, the volume isn’t necessary anymore, and now the same kind of work can be done in all kinds of different environments, allowing for more impactful performances and aesthetics.
It feels like it was only a few years ago that performance-capture technology was revolutionized by Peter Jackson’s Lord of the Rings films, but the reality is that it has come an incredible distance in the last decade-and-a-half.