ShotPlots

Guides · Guide 08

The 180 degree rule and the axis of action

The axis of action is an imaginary line between two characters. Keep the camera on one side of it and the audience always knows who is on the left and who is on the right. Draw it on the plan and the whole crew can see where the camera must not go.

Written by Richard Jones, film producer, Australia · Updated 13 October 2026

Two actors facing each other along a dashed 180 degree line, with two cameras placed on the same side of the line, each aimed across at the actor opposite.
Screenshot of the app canvas · two-person scene Axis line, two cameras on one side of it

What the rule says

Picture two people talking. Draw a line through both of them and extend it in each direction. That is the axis. The 180 degree rule says to keep every camera on one side of that line. Cross it, and the two people swap sides on screen. One was on the left looking right, and now she is on the right looking left. The viewer can feel something has shifted, even if they cannot say what.

Why it is 180 degrees

The line divides the room into two half circles, each 180 degrees. Anywhere in the half you chose is a legal camera position: a wide, an over-the-shoulder, a close-up, a profile. They will all cut together smoothly because left and right stay the same.

The axis moves when the actors move

This is where plans help. In a static conversation the line is fixed. When an actor crosses the room, the line between them swings with them. If they walk past each other, the axis rotates, and a camera that was on the safe side can end up on the wrong one. Sketching the line at each mark shows you before you shoot.

Drawing it on a plan

1. Place the actors first

Put both characters where they start, and give them a facing. The line runs through their positions.

2. Draw one long line through both

Extend it well past the actors, to the walls or beyond. A short line gets ignored.

3. Mark the safe side

Put the camera on the side you chose and note it, for example "cameras north of line". Everyone should be able to tell, from the page, which half is allowed.

4. Redraw it for each new position

If the blocking changes the line, draw the new one. Two lines on one plan, labelled by shot, is better than a single line that is wrong half the time.

Two 180 degree lines on one plan. The first runs through Maya and Joel before he moves. The second runs through Maya and Joel's new mark, after he moves toward the bottom of the room. Two cameras sit below the first line.
Screenshot of the app canvas · the axis moves Joel moves from mark 1 to mark 2

Crossing it on purpose

Rules exist so you can break them knowingly. You can cross the axis cleanly in a few ways:

  • Move the camera across within the shot. The audience watches it happen and re-orients.
  • Cut to a neutral shot on the line. A shot straight along the axis has no left or right to confuse.
  • Let an actor change the axis. If a character moves, the line moves, and the new side is now correct.

The plan is where you decide this, not on the day.

More than two people

With a group, use the line between the two characters the scene is mainly about. If the focus shifts, draw a new line for that exchange. A table of four usually has several axes, and the plan should show whichever one each setup is using.

Try it

ShotPlots has a 180 degree line tool: drag it along the line the camera must not cross, and it prints with the plan. Draw one free, no account, nothing to install, or see a finished sheet and its PDF.

Related

How to make a blocking diagram, and Camera angle of view on a floor plan.