Stage Blocking & Sightline Director

Blocking

Actors on stage 4

Formation cue

Focal actor (who draws focus)

Actor 1

Set Piece

Set piece position (SL ↔ SR) center

Audience Readouts

Sightline coverage

Composition balance (SL / SR)

50% / 50%

Stage depth used

How it works

A director blocks a scene by placing actors so every seat can see the storytelling moment, and so the stage picture is visually balanced. This simulator scores both, live.

Sightline test (per seat, top-down):
d = distance from occluder center
    to segment(seat → focal actor)
seat is BLOCKED if d < occluder radius
    for any other actor or set piece
        strictly between seat and focus

Composition balance:
weight(actor) = 0.7 + 0.6 · depthFactor
   (a downstage actor reads "heavier"
    than one lost upstage)
SR% = Σweight(x>0) / Σweight(all)

Formation cues — classic blocking shapes (line, triangle, diagonal, scatter); actors walk to their new marks over ~1.5s, the way a stage manager calls a blocking change.
Focal actor — the performer the scene is built around right now (marked with a gold ring). Sightline coverage is measured to this actor specifically.
Sightline coverage — the seats colored green in the auditorium have an unobstructed line to the focal actor; red seats are masked by another actor or the set piece, exactly the problem a director checks for by walking the house.
Set piece — a furniture flat you can slide stage-left to stage-right; watch coverage drop as it crosses the sightline cone.
Composition balance — the rule-of-thirds instinct made numeric: how much of the stage's visual weight sits stage-right vs stage-left of centerline.

Clear sightline Blocked sightline Focal actor

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