180 Degree Rule

In filmmaking, the 180° rule is a guideline that shows that two characters in the same scene should always have the same left/right relationship to each other. If the camera passes over the imaginary axis it connects the two subjects, it is called crossing the line. The new shot, from the opposite side, is known as a reverse angle. Problems caused and solution of the 180 degree rule enables the audience to visually connect with unseen movement happening around and behind the subject and is important in the narration of battle scenes.

If you can imagine an actor walking or running in a direction then you can picture the path they are following as a line. If two actors are talking to each other then draw a line to connect the two places where they are standing and extend the line in each direction to the edges of the set. Even if there are many actors in the scene you can still draw a line connecting the two opposing sides of the action. All coverage should be shot from one side or the other of this imaginary line. The audience subconsciously forms a mental map of where the actors are located in the scene.