In a fascinating piece for Movie Insider, narrator Abby Tang explains how Marvel movies are started years ahead of filming by partnering The Third Floor, renowned visualization studio in Hollywood. The tool, known as Previs, allows the director to map out action scenes in the virtual world before any actors become involved. It also gives the film crew a good idea of what will be needed during filming.
These rough shots are called previs, short for previsualization. Essentially, this tool allows filmmakers to digitally map out how they want any given scene to look. Directors can then use the previs as a guide for how to film scenes, sometimes frame for frame, once everyone’s on set. …Marvel’s extensive use of visualization has helped the franchise maintain a coherent vision all the way through “Endgame.”