How are dual-role films shot?

Question

How are dual/double role films shot in which the actor is shown on the screen at the same time in the same or different z-index planes and are in a fight scene in which one actor is punching the other, especially on the face?I've heard of split filming and stitching the scene, green screen, and lastly computer processed overlays of the actor's face on another actor's body with the same build. The last one I've seen in The Social Network but I'm referring to films that were shot pre 2005.And it looks very real.

Answer 1

Most of these scenes are handled in less high-tech fashion. Simply put, the main actor is on-screen but the angle is such that you can't clearly see the face of his/her "double." This is especially true in action scenes, like the fistfights you mention. Usually, the "double" is played by a stunt person who resembles the main performer.

You're right, though, that CGI and compositing effects can now be used fairly inexpensively to make there scenes more realistic. BTW, in The Social Network, those twin brothers actually are twin brothers! They were "played" by the actual real-life rivals of Zuckerberg.