You can see how exponentially it grows.  The saving grace is that these are the setups required only if each character interacts directly with every other character and in practice the more characters you have, the less likely it is that they will all interact with everyone else.

Let’s look at where all those angles come from.  Here’s a scene with 3 players arranged in a triangle formation:

So we have 3 lines, each between 2 of the 3 characters in the scene.  If we pretend that we are only dealing with 2 characters, lets say A & C then we have another very simple scene with two setups and one line:

As another example here’s the equivalent with actors A & B and their cameras:

This is also fairly straight forward, two characters and each one has a close up.  To complete the thought process here are B & C:

So for total coverage, all we have to do is put these 3 different, 2-person scenes together and we have a 3-person scene in all it’s glory:

3 Characters, between them 3 of the 180 degree lines and 6 close ups for seven setups if you include a master shot.  Now, any experienced director will tell you that this is a lot of setups for a 3 person scene.  So we try to simplify it, and that works quite well:

Even if you have only directed  a little, this will look more comfortable and familiar.  Here’s an example of that scenario in action.  It has 2 extras who do not have to be considered in the coverage and 2 brothers standing side by side who can be treated as a single character for the purposes of coverage.  This rough cut of a scene from the film McLean’s Money uses a Steadicam shot as the master and then a simplified 3 setup plan from there.  This was directed by Gerald Lawson.

Here’s the exact layout of that scene and it’s coverage:

This level of coverage works well with up to 3 “characters” per scene.  In fact, because we are only prioritizing 2 “characters” in this scene it remains easy to deal with the compromise risk of the simplified setup, which is getting too far off the eye-lines of the main characters. Beyond a 3 person scene, the rules become surprisingly more rigid.

Adding Movement

Of course, all of this also applies to the a character moving between different positions through the course of a scene.  The only difference is that we obviously don’t need the angles between the two positions of the character that moves.  Here’s a simple example:

A simplified version of this scene requires only 3 setups by having camera 4 pan with actor A as they move across:

The trick with this is that camera 1 has to be moved to be on the same side of Line #1 as the reverse. It’s then possible to remove Cam 2 setup.  The upshot of all this is an approach to this scene that is both faster to shoot and easier to cut.

If we wanted to be on the other side of Line #2 for the second half of the scene, maybe because of background issues, it is possible to carry the audience across the line with a dolly or Steadicam move as Actor “A” walks:

As long as the editor stays on Cam 4 while the line is crossed, there’s no problem because the  line is crossed within the shot rather than between shots.  In this situation, cutting directly from Cam 1 to Cam 3 or from Cam 4′s first position to Cam 3 would be very disconcerting for the audience because it crosses the established line (#1) without establishing the new layout of the scene.

Summary

The big thing to remember about the line is that it exists primarily between characters and is only occasionally about the room.  One technique I’ve found useful in getting practice at working out coverage and the line is to look at films and tv shows and simply count the setups in a scene.  If it’s well directed, you will usually be surprised at how many setups there are and occasionally by how few there are.  If it’s not well directed, you’ll probably learn just as much by noticing the flaws and jarring moments!

On the many shoots where I’ve been asked at some point… “will this cut together?”,  the fastest way I’ve found to be sure is to play the scene in my head with the shots we’ve taken or are about to take and see if there’s a moment or a relationship between characters that is missing or jarring.  This takes a lot of concentration but is the fastest way I’ve found to be sure that you’ve got the scene.