Particles
Emit many small elements and let forces move them.
A particle system spawns elements over time from an emitter, gives each a lifetime, and moves them with forces until they die. You direct the statistics — rate, spread, speed, lifetime — rather than animating individuals.
An emitter can be a point, a shape, or another layer's silhouette, which is how a logo disintegrates into sparks.
When to reach for it#
- Sparks, embers, smoke, confetti, snow, dust, magic.
- Disintegration and assembly.
- Trails behind moving objects.
Parameters#
Particles per second. With lifetime, this sets how many exist at once — rate × lifetime is roughly the steady-state population.
How long each particle lives. Add variation or every particle dies at the same moment and the system pulses.
Initial speed and the cone it is fired into. Zero spread is a beam; 360° is an explosion.
Constant downward force. Negative floats things upward, which is most of what you need for smoke.
Particles that shrink as they age read as dissipating; ones that grow read as expanding gas.
A ramp sampled by age. Hot to cool is the whole of a convincing spark.
Things that catch people out#
Rate times lifetime is what you are actually asking for. Doubling the lifetime doubles the population even though the rate did not change.
See also#
Something here wrong or missing? Tell us in the community.