---
title: "Why particles become keys"
description: "Understand how one editable emitter becomes motion that an ordinary Lottie player can draw."
canonical: "https://terminal.lottiefiles.com/docs/concepts/particle-baking/"
last_updated: 2026-10-27
---

# Why particles become keys

Understand how one editable emitter becomes motion that an ordinary Lottie player can draw.

Lottie has no particle simulation. Creator Terminal turns the emitter's settings into keyed
copies of its artwork. Players receive those copies and keys, so they can play the flight
without running a particle engine.

You keep one emitter to edit. Its position, direction and other values decide where each
copy is born and how it moves. Changing the emitter recalculates the keyed flight. Clicking
a visible particle selects that emitter rather than asking you to edit hundreds of copies.

There are two kinds of time. The score (the timeline) times the emitter and its controls.
**over life** runs from each particle's birth to its death. A younger particle can still be
large and opaque while an older particle beside it has shrunk and faded.

A particle takes its settings at birth. Keying **Rate** changes the flow for future births.
It does not change how many copies a particle already alive turns into. Shortening
**Lifetime** reduces the number alive together, not the total number born.

The seed makes variation repeatable. The same seed and settings produce the same flight,
which lets you scrub or export the same result. **next** gives another arrangement while
keeping the other settings.

Every copy adds keys and file size. This is why an emitter has a 500-particle cap over its
time, even when only a few are visible at once. Lower the rate or emission time when the
rail says **the most**.

Next: [Particle controls](https://terminal.lottiefiles.com/docs/particles.md#the-rail), or
[use your artwork as particles](https://terminal.lottiefiles.com/docs/how-to/use-artwork-as-particles.md).