1. Exact containment
Every pose is an oriented polygon checked against the outer walls, inside corner and modeled door jambs.
LOCAL 2D PATH LAB · EDITABLE SAMPLE
Will the sofa fit through the door and make the turn?
Drag the start and goal, enter the real corridor and door dimensions, then search for a collision-free rigid path. You get the route—not a vague yes/no.
Editable sample scene
No decision yet. Change any dimension or drag a handle.
Drag · Arrow keys: 10 mm · Shift: 50 mm · Q/E: rotate
DECISION
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Evidence pack
Coverage, unsupported surfaces + exact path
| Step | X | Y | Angle | Clearance |
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CLASSIC MOVING SOFA MATH LAB
The famous problem is stranger than a real sofa.
The mathematical problem asks for the largest connected 2D shape that can turn through an ideal unit-width right-angle hallway. Jineon Baek’s 2024 preprints concern that ideal optimization problem. This tool does something deliberately narrower: it searches a route for one rigid rectangle in your entered dimensions.
Boundary, not marketing
A preprint result is not proof that your sofa fits. Our practical PASS also does not model height, tilt, flex, stairs, hardware, hands or moving safety.
Baek 2024: Optimality of Gerver’s Sofa
Baek 2024: conditional upper bound
WHY THIS RESULT IS DIFFERENT
A route you can inspect, not a confident guess.
2. Whole-transition certificate
A conservative motion bound recursively certifies the space between search states. A sampled route alone cannot PASS.
3. Recheckable handoff
SVG, CSV, JSON, Markdown and no-script HTML bytes are SHA-256-bound by Receipt v1 for independent mutation checks.