Stopping is a coupling problem, not a rendering one
P8 and P10 said the flow was not theirs because nothing could stop it. On the water, holding water is an action with an immediate consequence. In RowSim, stopping is only the absence of drive, resolved by a decay the rower waits out. What specifies self-motion is not motion in the visual field but motion that varies with what the observer does.[128] A display that accelerates on demand and decelerates on its own schedule supplies half of that.
This is not a rendering failure. The field already answers the drive. Wulf’s work on external focus treats consequence as something the mover can aim at;[136] here the missing consequence is arrest. Decay is not hold water. The Concept2 flywheel has the same gap: stopping on a standard erg is coast-down, not a commanded brake. RowSim’s missing arrest is shared with the machine, not unique to the floor. Restoring the missing motion is a coupling problem.[Th.]
- 01DriveThe field rises with the stroke.
- 02DecayThe rower stops. The field keeps moving.
- 03Hold waterA commanded brake would drop the field with the blade. The erg flywheel has no arrest either — only coast-down.
Arrest
Stopping was not commandable.
DriveThe field rises with the stroke.
Starting motion is commandable. Arresting motion is only decay. Hold water is the missing input.
What this floor licenses
Coupling first: the stroke has to answer immediately. Then openness, arrest, register, and goal. Each rests on seventeen participants, one prototype, one palette, one laboratory and a single exposure, so each is an observation with a boundary, not a law. Weiser and Brown doubted calm technology would survive a working body;[128] Pousman and Stasko’s ambient-display patterns largely stayed in offices.[096] The floor is a test of whether that boundary was necessary. Gaver’s ambiguity is still the mapping they were handed.[047]
Design considerations
Coupling first.
01 · CouplingThe stroke has to answer immediately. Palette and completeness can move; the mapping cannot lag.
Coupling as the wall. Openness, arrest, register, and goal occupy the rooms — negotiable, not structural.
Physical continuity, perceptual craft
The field has to be incompressible to read as fluid, and it has to be crafted to remain legible under two projectors on a sheet. Those are facing requirements, not a sequence.
Hybrid model
Two truths, one fluid.
Physics buys continuity; craft buys legibility under projection.
01 · PhysicsStable-fluid advection and pressure projection buy coherent motion — continuity before beauty.
Physical continuity and perceptual craft as facing truths that meet in the floor visualization.
The floor changes the evaluation question
Once the display is on the floor, “working” is no longer only whether the solver is stable. It is whether attention stays in the stroke, and whether the visualization is readable from the seat.
When the display is the floor
Embodiment
The floor changes the question.
01 · WasNecessary — but not what “working” means once the display is on the floor.
When the display is the floor, the evaluation question shifts from solver stability to embodied feedback.
Keep implemented, found, and released apart
The repository can prove kernels, sensing, and host physics. The study can prove what seventeen people did and said. Craft can disclose hybrids and palettes. Those are different kinds of claim. Mixing them is how a companion site becomes a second thesis, or a demo that pretends to be a finding.
Evidence policy
Keep the seam visible.
01 · BuiltSource-grounded technical claims — what the repository can prove today.
Three claim lanes stay separate above a visible integrity seam. The empirical loop is closed.