Simulations
A simulation is a live model on the slide — a pendulum, a wave, a spring — that runs at full frame rate while you present, and that the audience watches move.
Adding a simulation#
Insert a simulation (S) and choose a model in the inspector — pendulum, wave, spring, and more. Set its physical parameters (length, gravity, speed) and it begins to animate on the slide.
Unlike a chart, a simulation is not a snapshot of a result; it is the result, running. It keeps animating in the editor, in present mode, and in the audience window you share into a call.
A new simulation arrives as a running, looping pendulum, so the slide is alive the moment you place it. Resize the object and the model re-lays itself into the new box rather than scaling like a picture: the pivot stays at the top of the stage, and the readout keeps its own size underneath.
The five models#
Model is a segmented control at the top of the inspector, and switching it swaps the drawing and the physics together. Each model shows only the knobs it actually has: offering a pendulum its eccentricity would be offering a number that changes nothing.
| Model | Its own physics | What it draws |
|---|---|---|
| Pendulum | Length ℓ and gravity g | A bob on a rod from a fixed pivot, swinging with period 2π√(ℓ/g). |
| Spring | Stiffness k, mass m, amplitude | A mass on a dashed spring line oscillating at ω = √(k/m). |
| Orbit | Eccentricity and frequency | A body on a conic path around a fixed centre. |
| Projectile | Launch speed v₀, angle θ, gravity g | One flight from launch to landing, scaled into the object's box. |
| Wave | Amplitude and frequency | A bead riding a standing waveform. |
Pendulum, spring and wave also take Damping — the fraction of amplitude lost per second, zero being undamped.
Under the animation, a Readout line reports the numbers that matter for that model as it runs: ℓ 1.0m · g 9.8 · T 2.01s for the pendulum, k 8 · m 1 · ω 2.83 for the spring, e 0.35 · T 2.9s for an orbit. Turn it off when the slide should carry the point on its own.
Controls#
The inspector controls the model and its parameters:
- Speed — how fast it runs.
- Loop — whether it repeats, or plays once and rests.
- Trace — leave a path behind the moving body.
Because a simulation renders itself frame by frame, it costs almost nothing to keep on screen — you can leave it running through a whole talk.
Playback holds the rest: a Status badge reading live or ready, a Play / Pause button, the speed, and Repeat set to Once or Loop. On Once the model completes one cycle and stops itself — a derived change, so it never lands in your undo history. Display adds Grid, Colour and a Caption beside the trace and readout switches.
A dot beside the readout lights while the model is running, so a paused simulation never reads as a broken one. Pausing returns the body to its starting position rather than freezing it mid-swing, and clears the trace — so pressing play always begins the path afresh.
Simulations and parameters#
A simulation's inputs can be tied to parameters, so dragging a slider changes the model live — scrub gravity and watch the pendulum's period change in front of the room.
Each model offers exactly its own knobs as binding slots, in the units an audience reads them in, plus playback speed:
- Pendulum — length in m, gravity in m/s², damping.
- Spring — mass in kg, stiffness in N/m, damping.
- Projectile — launch angle in degrees, launch speed in m/s, gravity in m/s².
- Wave — amplitude, frequency in Hz, damping.
- Orbit — eccentricity.
Wiring a slider to one of these re-homes it: connect a fresh parameter to a pendulum's length and the slider adopts the range that length is meaningful over, instead of yanking the pendulum to whatever the slider happened to be created with.
A simulation is at its best as the thing you return to: set it running, talk through the theory beside it, then point back at it with the laser.
Bind the same parameter to two objects and they move together: gravity feeding both a pendulum and a projectile makes one slider the single fact both models obey.
While you present#
The editor's presenter view supports live simulation controls, subject to the parameter panel's presentation policy. Shared links and embeds use a read-only slide viewer: an animation may render, but viewers cannot drive the same live parameter-and-computation workflow. See Who may move a parameter and Collaboration.
Next#
- Reactive documents — drive a simulation from a parameter.
- Presenting — the simulation stays live while you talk.