In filmmaking, the 180-degree rule is a basic guideline regarding the on-screen spatial relationship between a character and another character or object within a scene. The rule states that the camera should be kept on one side of an imaginary axis between two characters, so that the first character is always frame right of the second character. Moving the camera over the axis is called jumping the line or crossing the line; breaking the 180-degree rule by shooting on all sides is known as shooting in the round.
The 180-degree rule enables the audience to visually connect with unseen movement happening around and behind the immediate subject and is particularly important in the narration of battle scenes.
