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Particles and sequences

RocketClick the rocket to launchlive
Rocket: the first frame. Press play to run it live.

Click the rocket (or press launch): smoke, exhaust and sparks are three particle emitters keyed by the launch animation.

Add an emitter

Section titled “Add an emitter”
  1. Select the slot that should emit (usually on a bone you can move, like the rocket’s nozzle).
  2. In the Inspector choose + Particles… and pick a preset: fire, smoke, sparks, confetti, exhaust or coins. Or start empty.
  3. Tune it in the Particles section:
    • Emission: emitting on or off, rate per second, a maximum, duration, loop, prewarm and bursts (a count at a time in each cycle);
    • Shape: point, circle, box or cone, and world or local space;
    • Life: lifetime, speed, gravity, drag;
    • Over life: size, rotation and colour curves;
    • Look: dots, squares, sparks or any image in the document as the particle.
  4. ★ Save as preset… keeps your settings as your own preset, available in every project.
The Rocket mid-launch with exhaust particles below it; the exhaust slot's particles section in the Inspector with preset, emission rate 90, max 200, duration, loop, prewarm and the cone shape; the timeline with emitting and rate keys
The exhaust emitter during the launch. Emitting and Rate are keyed in the timeline, so the animation turns the exhaust on and up.

Particles are seeded, so the editor’s preview, Play mode, the runtimes and the video exports all show the same particles frame for frame.

Drive emitters

Section titled “Drive emitters”
  • Keys: emitting and rate are animatable properties (the ◆ next to them).
  • Listeners: the start particles action bursts an emitter on a click.
  • States: a state’s animation keys the emitters it needs, so the state machine turns them on and off.
Play mode on the Rocket after the launch trigger: the rocket lifting off the pad with smoke and sparks, and the Inputs panel with the launch trigger and the log
Play mode after firing launch: the state machine plays the launch animation, which starts the emitters.

Sprite sequences

Section titled “Sprite sequences”

For effects drawn frame by frame (flames, explosions, a blinking light), use a sequence attachment: + Add → Sequence takes numbered images (fire_0001.png…), a sprite sheet (a grid, TexturePacker or Aseprite JSON) or a ZIP of frames. Each sequence has its own fps and mode (loop, once, ping-pong, hold last), and can be driven by time, by keys or by a number input.

The Campfire: sequence flames in front of logs, with the flame slot's sequence attachment in the Inspector: frame preview 12 of 12, playback controls, fps 15, loop mode, driven by time
Campfire: two flame sequences (additive blend), a bending flame mesh and a clipping mask for the stones in front.
Campfirelive
Campfire: the first frame. Press play to run it live.

OpenBone is MIT licensed and made by UXCentury. The example art, voices and sounds are credited in the repository.