Preview identical to the file
Preview and export call the same simulation and drawing functions. That equality is checked frame by frame, with zero pixel tolerance.
Physics simulation that becomes a finished video
Tune the parameters, watch the simulation live and export an MP4 with synced audio. What you see in the preview is exactly the file you get.
- Nothing to install
- No uploads
- Preview identical to the file
Three steps, no uploads
- 01
Pick the scene and the seed
Every seed is a whole variation of the simulation. The search evaluates dozens in the background and shows which ones end well.
- 02
Tune it while it runs
Changing a parameter re-simulates from the start, and the first new frame shows up in under 150 ms.
- 03
Export the MP4
WebCodecs encodes faster than real time, with a soundtrack derived from the collisions.
Enough to publish, and nothing more
Export without a server
WebCodecs encodes in your browser. Unlimited, with a discreet watermark.
Seed curation
Simulates without drawing, scores the outcome and ranks the candidates. Never spends credit.
Deterministic audio
Every collision becomes a note in the chosen scale, synced to the impact that produced it.
Server-side render
When the browser cannot encode — or you want it without a watermark — the same recipe runs in an isolated lane and returns the same file.
Determinism
The same seed produces the same video on any machine
On every change, the project compares the simulation state after 2,000 steps against recorded vectors — in Chromium, Firefox, WebKit and Node. If one hash diverges, the merge does not happen.
That is what makes “the preview is the file” a structural property rather than a synchronisation effort.
| simulation | seed | hash |
|---|---|---|
| bouncing-ball-in-circle | 0 | 59170d19a860a390 |
| bouncing-ball-in-circle | 1 | c57360956b8649b4 |
| bouncing-ball-in-circle | 42 | aa2b8b98d9e7ec20 |
Preview and export are free and unlimited
The render happens on your computer — so it costs us nothing, and we do not need to charge for it. An account is only needed to save projects and for the paid features.
Start without an account