Virtual camera system are required for fourth person view.
  In computing subsequent suggested virtual camera shots, the system analyzes the visual compositions and editing patterns of prior recorded shots to compute suggested camera shots that conform to continuity conventions such as not crossing the line of action, match placement of virtual characters so they appear to look at one another across cuts, and favors those shots which the human operator had previously used in sequence
== Real-time recording and motion tracking ==Virtual cameras have been developed which allow a director to film motion capture and view the digital characters movements in real time in a pre-constructed digital environment, such as a house or spaceship

