Mechanisms, written as code

Describe a machine.
Watch it move.

A CSS-like language for mechanisms. Say how the parts connect, drive one, and GearScript animates the rest in 3D, right in your browser.

Open the Studio See an example
Free · open source · no sign-up · nothing to install
01 · Paths

Send parts along a path.

Give a part a curve and a lap time, and it follows. GearScript works out where it is at every moment.

r(θ) = a(1 − e²) ⁄ (1 + e cos θ)
θ = 0°r = 0 kmv = 0 km/s
Probe { forever: along: Orbit 12s; }
02 · Timing

Say when, not every frame.

Give a start time and an end time. GearScript fills in every moment in between, with the easings you know from CSS.

Probe {
  0s..4s: rotate: 0deg -> 180deg ease-in-out;
}
t = 0.00 srotate = 0°
Drag the slider: the satellite turns exactly as the rule says.
03 · Connections

Connect parts and they move together.

Hinges, sliders, gears, belts and pins are built in. Swing the first panel and the rest follow.

Wing2::Plate { hinge: edge.left on Wing1.edge.right; }
Mast::Rod    { slider: axis on Body.face.top; }
04 · Light and sound

Add light and sound.

Parts can glow, and sounds play on cue. Every sound is generated, so all of it is free to use.

Beacon { luminosity: 0 -> 100%; }
Probe  { sound: Ping every 1.5s; }
05 · Examples

Real machines, no keyframes.

Open any one to watch it run and read its code.

8 LOOPS
A V8 engine with eight pistons on one crankshaft
V8 engineclosed loops, one belt
 46 PARTS
A skeleton wall clock with its pendulum and weights
Pendulum clockassembles, then ticks
 WALKS
A humanoid robot walking on a treadmill
Walking robotlegs and arms in step
 STEAM
A steam locomotive with coupling rods
Locomotiverods, crosshead, valve gear
 LIGHT
A lighthouse at dusk with a turning beam
Lighthouseluminous lamp and beam
 ORBITS
The solar system with planets on their orbits
Solar systemorbits within orbits
06 · Errors and AI

Errors that tell you the fix.

Every message says how to fix it, so AI assistants can fix their own code too.

W0560 Probe and Shield pass through each other at 3.2 s.
fix: move one of them, or connect them with a hinge.
07 · Get started

Start with one line.

Crank { forever: rotate: 180deg/s; }   // half a turn every second

Try an example, then export a video, a GIF or a 3D page.

Open the Studio Read the documentation
Intro