The 180 Degree Rule

When making a film, the 180-degree rule is a fundamental editing technique. It is a basic guideline concerning the spatial relationships between characters on screen. It can also be done with a character and an object within a scene. The rule is that every individual in a scene must have the same left-right relationship and the camera stays behind an invisible line which is perpendicular to the cameras viewpoint. A diagram that displays it perfectly is below.