Never Cross the Line: The "180 Degree Rule"

180-Degree Rule

What is "Crossing the Line?", and why should animators never (or, almost never) cross it?

"Crossing the Line" is also known as the "180-Degree Rule", and it is one of the fundamental rules of cinematography.

Like most rules of film-making, the only way to really understand the 180 Degree Rule is to break it, figure out what went wrong - and then work out how to fix it next time.

Let's say you have a shot with two characters talking to one another. Draw an imaginary line between the two characters. This is the "line" that we should not cross.