Scene
Closing gate
Escape the ring plus the shrinking circle: the gap spins while the radius shrinks. Every near miss costs time, and time is space.
Open Closing gate in the editor
Parameters
The same controls as the editor, with the same range. The default is what the example page uses.
| Parameter | Range | Default |
|---|---|---|
| Shrink rate | 0 – 1.5 | 0.14 |
| Gap | 10 – 120 | 40 |
| Angular speed | -8 – 8 | 1.4 |
| Balls | 1 – 8 | 1 |
| Gravity | 0 – 40 | 12 |
| Bounciness | 0 – 1 | 0.95 |
| Minimum radius | 0.5 – 4 | 1.2 |
| Initial speed | 0 – 30 | 4.5 |
| Growth per collision | 0 – 0.2 | 0 |
How it usually ends
Measured by the engine with the default configuration over a fixed sample of seeds. No number here is an estimate.
- Seeds in the sample
- 40
- Escapes
- 98%
- Settles
- 3%
- Times out
- 0%
- Collisions (median)
- 5
- Duration (median)
- 4.2 s
- Climax (median position)
- 44%
- The fraction of the video where event density peaks. Close to 100% means the best moment is at the end.
Seeds that end well
The five best in the sample by the same heuristic the editor's search uses. Each link opens exactly this variation.
- seed2630570score 74 out of 10051 collisions20.4 ssettledOpen seed 2630570 in the editor
- seed1583280score 61 out of 1008 collisions8.1 sescapeOpen seed 1583280 in the editor
- seed3782589score 58 out of 10012 collisions9.2 sescapeOpen seed 3782589 in the editor
- seed1897467score 55 out of 10010 collisions7.2 sescapeOpen seed 1897467 in the editor
- seed3887318score 51 out of 10016 collisions12 sescapeOpen seed 3887318 in the editor
Watch
Videos of this scene published by the channel, each with the recipe that produced it.
Four Balls, a Shrinking Gate — Simbounce
Closing gate · Sep 12, 2026
The gate kept spinning and the arena kept closing in around four growing balls. It took 95 hits, with everything deciding in the very last moments before the space ran out. Physics simulation, no cuts, no scripting.
scene95 collisionsView the video and the recipeFour Balls, One Closing Gate — Simbounce
Closing gate · Sep 10, 2026
Four balls chased a single rotating gate while the arena kept shrinking around them — 94 hits later, there was no room left to move. Physics sim, no cuts, no scripting.
scene94 collisionsView the video and the recipeThe Gate Never Opens In Time — Simbounce
Closing gate · Sep 9, 2026
Three balls chased a single rotating gate as the arena kept closing in — the opening never quite lined up. 117 hits later, there was nowhere left to go. Physics sim, no cuts, no scripting.
scene117 collisionsView the video and the recipe
Frequently asked questions
How do I make a Closing gate video?
Open the scene in the editor, adjust the parameters, try a few seeds and export to MP4. Rendering happens in your browser and costs nothing.
Why does the same seed always give the same video?
The simulation is deterministic: fixed-step physics and seeded random numbers. The same seed with the same parameters reproduces the same video on any machine.
How long is a Closing gate video?
The video ends when the scene ends. The median duration measured in the sample is in the outcomes section, and the seed search shows each candidate's duration before rendering.
Can I use the video on TikTok, YouTube and Instagram?
Yes. The export is a vertical video with audio, ready for Shorts, Reels and TikTok. On the free plan it carries a discreet watermark.
How do I pick a seed that ends well?
Use the editor's seed search: it simulates dozens of variations without drawing and ranks the ones with a late climax. The seeds on this page came from the same heuristic.
Make your own variation
Open the scene in the editor with one of the seeds above, or let the search find another.
Open Closing gate in the editor