After 10 films and billions of dollars in the bank, Marvel Studios knows a thing or two about how to launch superhero franchises. From its left-of-center casting and director selections to its deep understanding of the Marvel roster, the studio's success owes thanks to a number of factors — but one that doesn't get too much play is its reliance on reshoots.

Marvel Studios President Kevin Feige opened up on the topic of reshoots in an interview with Badass Digest, explaining why it's critical for the success of films like Avengers, Thor and more to build additional shooting into the structure of any given Marvel movie.

"Additional photography is invaluable," he said. "Sometimes it's to fix something that's not working, but most of the time on our movies it's two-fold: sometimes a better or more exciting idea will come along, or more often something will come out of the movie — because it's too long or the movie is stronger without a particular beat or scene or shot, and you need connective tissue."

As an example, there's a scene in Thor: The Dark World that came together after principal photography wrapped, in the form of what Feige and Marvel refer to as "the Three Continent shot."

"It's one shot, with three different actors in it, that was done on three different continents," he said.

In other words, although Joss Whedon has wrapped principal photography on Avengers: Age of Ultron, expect there to be reshoots as the film comes together — because, according to Feige, the movie only truly comes alive once the first wave of shooting ends.

"Post is my favorite part," he said, "because it's easiest to find what's wrong with the movie when you're watching the movie."