Set up script days
Script days are story days, not shooting days. SceneMatch can work them out from the script automatically — a new day begins wherever the clock goes backwards — and keeps flashbacks separate.
A script day is a day in the story. Scene 12 and scene 40 might be shot three weeks apart and still be the same afternoon as far as the audience is concerned — which is exactly why continuity cares.
They are not shooting days, which are days of the production's life. Nearly every continuity error comes from confusing the two.
Why they matter
Script days are what tell you that a character has to look the same in two scenes. If scenes 12 and 40 are both Day 3, the hair, the costume and the state of the cut on his cheek must match — regardless of when they were filmed.
Once scenes carry script days, that question stops being someone's memory and becomes something the production can look up.
Generating them from the script
You do not have to assign these by hand. SceneMatch can build the script days from the screenplay, and the rule it uses is simple enough to predict:
It reads each scene's time of day — morning, day, evening, night — in script order, and starts a new script day whenever the clock goes backwards. A night scene followed by a morning scene means the story has moved to the next day. A run of morning-to-night scenes stays on one.
That is the same reasoning a script supervisor applies, which is why the result is usually close to right on a first pass.
You can generate starting from a chosen day number, which matters for a season where episode 2 continues counting from where episode 1 finished rather than restarting at Day 1.
Flashbacks are recognised
A scene whose location is marked as a flashback is not folded into the running day count. It becomes a flashback script day of its own, keyed to that scene, so it does not silently absorb the scenes around it or push the numbering along.
There are three types in total: day, flashback and flashforward. Numbers only have to be unique within a type, so Day 1 and Flashback 1 can both exist.
Your assignments are respected
Auto-generation only fills in scenes that do not already have a script day. A scene you have assigned by hand keeps what you gave it, and the generator works around it.
So the practical workflow is: generate, then correct the handful the script was ambiguous about — and generate again later, after a revision, without losing your corrections.
Seasons
A script day can carry a season — winter, spring, summer or autumn. On a production that spans a year in the story, this is what stops a summer scene being matched against a winter one.
The thing that is not obvious
Auto-generation is a reading of the script, not a fact about it. It works from time-of-day markers in the slug lines, so a script that is vague about them produces vague script days. Scenes with no time of day at all simply continue the current day.
It is worth a read-through after generating, particularly around any scene where the story jumps. The generator cannot know that three months pass between scene 60 and scene 61 unless the slug lines say so — that is the kind of thing you correct once and it stays corrected.
On a season
Script days live at the season level and each episode contributes its own, so the season has one continuous timeline rather than each episode restarting. Generate per episode; the production's list grows to hold all of them. See building a season.