Particles
A particle emitter is a layer. Create one with Particle System in the toolbar’s New Layer menu. Its controls are the Particle settings section of the Properties panel.
Parameters
| Parameter | Controls |
|---|---|
| Rate | Particles emitted per second |
| Lifetime | How long each particle lives |
| Velocity | Initial speed and direction |
| Gravity | Constant acceleration |
| Turbulence | Noise-driven displacement over the field |
| Size over life | How a particle scales as it ages |
| Colour over life | How it tints as it ages |
The numeric fields are keyframeable. So the emitter’s rate, gravity and turbulence can all animate — a burst is a rate spike, not a separate emitter.
Beyond the basics, the section also holds:
| Control | What it adds |
|---|---|
| Emitter type | Including a sphere emitter |
| Drag / air damping | Particles slow down instead of flying forever |
| Particle collisions, Floor Y, Bounce restitution | In the stateful simulation mode, particles can land and bounce |
| Sub-emitter | A trigger, children per burst, child speed and lifetime — sparks that throw sparks |
| Trails | Trail points and spacing, for velocity streaks |
| Particle shape and sprite | A sprite image, or a sprite sheet with its own frame rate |
| Plexus | Lines and triangles between nearby particles |
| Transfer mode | How particles composite onto each other |
Baking
Animation → Bake → Bake Particles to Layers… converts each particle into its own keyframed layer and hides the emitter. It is how you art-direct a simulation: once baked, a particle is an ordinary layer you can move by hand.
Determinism
The emitter is deterministic: the same frame always produces the same field.
That is not a detail. It means:
- An export is reproducible. Render twice, get identical files.
- A re-render after a crash resumes identical work rather than producing a different-looking second half.
- Scrubbing backwards shows the truth. The field at frame 120 is the same whether you arrived there by playing forward or by dragging the playhead.
- The pixel-comparison test harness can test particles at all, which a wall-clock-seeded emitter could not be.
It follows from the same rule as the rest of the render path: frame time is
index / fps, never wall-clock. See Determinism.
Practical recipes
A burst. Keyframe rate from 0 to a high value for two or three frames, then back to 0. Give the particles a short lifetime and high initial velocity.
Ambient drift. Low rate, long lifetime, low velocity, a little turbulence, gravity at or near zero. Fade with colour-over-life rather than opacity keyframes so each particle fades on its own schedule.
Falling. Emit across the top of the frame, positive gravity, lifetime long enough to cross the composition. Add turbulence so they do not fall in parallel lines.
Cost
A dense emitter is expensive to render. If the viewport becomes sluggish:
- Turn on Draft 3D if the scene is 3D.
- Turn on View ▸ Viewport ▸ Performance HUD to see what the engine is actually spending per frame.
- Reduce rate while animating and raise it before the final render — it is a keyframeable parameter, so remember to check the keys before exporting.