# Scene Geometry and Spatial Continuity

## Lesson Outcome

A camera changes the viewpoint, not the world. If you do not lock that down, the door, character, prop, and lighting begin separate lives whenever the angle changes. A shot can still look dramatic. It is simply no longer the same room.

In this lesson, you will build a simple spatial map: where characters and fixed props are, where eyelines and movement go, where the light comes from, and what has genuinely changed through an action. You do not need a map for every isolated shot. You need one when the viewer must believe that several shots happen in the same place.

```learner-callout
{"stable_id":"aiv-c052-world-not-frame","role":"key-point","title":"Key point: the scene world is not the frame","body":"The scene world holds positions, landmarks, and state. A frame shows only the portion selected by the camera. An object leaving the image does not mean it left the scene."}
```

---

## Picture the Whole Room First

Take a room with two people, a table, a door, and a lamp. The scene world answers “Where is everything?” The frame answers a different question: “Which part of that place does the camera show now?”

The camera moves closer to a face, and the door leaves the image. The door has not left the room. The next viewpoint can show it again because it observes another part of the same space; it does not rebuild the room between shots.

A separate map is especially useful when a location returns in several shots, sides and distances matter, a character interacts with a fixed prop, matching and reverse angles are used, or a position error would break the action itself. You do not need to file a cadastral map of Mars for one person in an empty field and three seconds of wind.

## What to Lock Before the Next Angle

“The table is nearby” holds almost nothing. Near whom? In front of the character or behind them? A better note is: “The table stands between the characters; the recruiter sits on the far side, the candidate on the near side; the door remains behind the recruiter’s right shoulder.”

Build this map once for a recurring scene:

```template
Fixed landmarks:
Character positions:
Main prop position:
Main line of action:
Which side the camera occupies:
Eyeline and movement directions:
Main light direction:
What has already changed and cannot undo itself:
```

```learner-callout
{"stable_id":"aiv-c052-map-technique","role":"technique","title":"Technique: write relationships, not vague words","body":"Record not just the prop but its relation to other things: between whom the table stands, behind whose shoulder the door sits, which side the camera occupies, and where an eyeline goes. You can check those statements in a new angle."}
```

## Axis, Screen Sides, and Eyelines

You can draw an imaginary line between two people who are speaking or acting. This is the **line of action**, also called the scene axis: a simple boundary that helps the viewer understand who is left, who is right, and whether the eyelines meet.

While the camera stays on one side of that line, the direction remains stable. You may cross the axis when the transition is readable: the camera visibly crosses the line, a character changes position, a neutral shot looks along the axis, or a new wide shot establishes the space again.

```learner-callout
{"stable_id":"aiv-c052-axis-caution","role":"caution","title":"Caution: a random jump is not a technique","body":"If the camera suddenly appears on the other side of the axis without a readable transition, the viewer can lose the screen sides and eyeline direction. It is not an artistic device; it is an accidental jump wearing an expensive coat."}
```

When the image side matters, write “left side of the finished frame” and “right side of the finished frame.” Do not confuse this with the character’s right and left hand. An eyeline works like an arrow too: a person looks beyond the frame edge, and the viewer expects the object on the corresponding side in the next shot.

## Prop Visibility Is Not Prop State

A prop raises two independent questions. First: is it visible in the current frame—fully visible, partly blocked or cropped, or behind the camera and outside this angle? Second: what happened to it in the scene world—unchanged, moved by an action, altered by an action, or removed by an action?

A phone lies on the table. It is absent from a close-up of a face, and it may still be in the same place in the next wide shot. But if it appears in a hand without an action, causality has broken, not merely the composition.

```learner-callout
{"stable_id":"aiv-c052-prop-state","role":"observation","title":"Observation: a frame can hide a prop without canceling it","body":"Mark “out of frame” separately from “changed in the world.” This protects a scene from props that teleport, vanish, or return without an action."}
```

---

## Filled Example: a Short Job Interview

In a short job-interview scene, a rectangular table and two chairs are fixed landmarks. The door is behind the recruiter, and the lamp is by the room’s left wall. The candidate sits on the near side of the table, the recruiter opposite; one sheet of paper lies closer to the recruiter.

The axis runs between their faces along the table. Matching and reverse cameras stay between that axis and the room’s right wall, opposite the lamp. In their single, the candidate looks right; the recruiter looks left. Soft side light comes from the lamp: its side in the image may change with the viewpoint, but the light source stays in the same place in the room.

You can now show the wide view, the candidate, the recruiter, the paper, and a reaction. Each frame reveals different information, but the room remains the same.

![AIS FLOWS case — several approved views of one meeting room](./_assets/apply-vision-pro-owner-case/location-coverage-grid.jpeg)

*AIS FLOWS case: Apply Vision Pro. Several views of one meeting room help preserve the table, door, lighting, and screen sides across changing viewpoints.*

## Practice and Check

Create a map for one recurring scene with the form above. Then describe two different viewpoints and record separately what changed only because the camera moved, what changed in the world through an action, and what temporarily left the frame.

```learner-callout
{"stable_id":"aiv-c052-spatial-practice","role":"practice","title":"Practice: describe two angles without inventing a new room","body":"The first angle can be a wide shot and the second a close-up of one character. Compare the second with the map: did the door, table, eyeline, light source, or main prop state change without a reason?"}
```

```learner-callout
{"stable_id":"aiv-c052-spatial-checkpoint","role":"checkpoint","title":"Checkpoint: the map explains the scene to someone else","body":"You have completed the lesson when another person can use the map to name character and prop positions, eyelines and movement, what stays in place, and which prop disappeared only from the frame. If answers differ, clarify one position or direction and check again."}
```

**Takeaway:** you now have stable scene geography, not a description of a beautiful room that every new shot has to rebuild.