An emitter decides where particles come from, when they may exist, and how their starting places are spread inside whatever shape you picked. A Particle Solver has one emitter — but that emitter can fire from up to four layers at once, in any of eight shapes, with any of eleven ways of spreading its spawn sites.
There is no second emitter with its own rate and lifetime; what stands in for one is several sources on the emitter you have.
The emitter
- Emit — Continuous keeps emitting for the whole clip at the rate below; Static fills the system once and never emits again (one cloud, born together). Static is the one for a shatter, a title made of dust, or anything Particle Activation is going to release.
- Emit from — Point, Box, Sphere, Cone, Ring, Path, Block or A layer.
- Position and Size place and size the emitter inside the Solver Box.
- Rate — particles per second.
- Pulses — one-off bursts on top of the rate, each with its own count and Fires at time. They are chips: add as many as you want, remove them down to none, and Spread distributes the pulses you have evenly across the clip while keeping their counts. A pulse emits its whole count in one frame — the launch Speed throws the front out and Drag stops it.
- Spread — the cone angle around Direction, from a tight jet at 0° to every direction at 180°.
- Lifetime / Lifetime ± and Speed / Speed ± — the value and how much it varies per particle.
Ring and Path add their own geometry — a ring has a Radius and Thickness, a path is a spline you draw with up to 64 anchors — and both offer a Launch mode besides the cone: Outward (normal to the shape) or Tangent (along it). A ring firing tangentially is a smoke ring; a path firing tangentially is a stream that follows a drawn line.
Emit from a layer — dissolve a picture into its own pixels
Set Emit from to A layer and pick an image, text or shape layer from the timeline. Particles are then born on that layer’s opaque pixels, and the emitter takes the layer’s real on-screen rect and position — so the dissolve starts as an exact copy of the layer, in its place, at its size.
Picking a layer also sets the system up for a dissolve, because inheriting a drifting preset reads as broken: no pre-roll (the picture must be whole at the start, not already blown apart), the whole particle count in one pulse at frame 0, no launch speed — the forces do the moving — and a ramp that is opaque first and fades later. Dot size is matched to the spacing of the sampled pixels, erring toward overlap so the picture reads solid before it breaks up.
To keep each speck’s own colour, set Colour by to Source in PARTICLE COLOUR. The ramp then drives only the fade, which is what makes it look like the picture coming apart rather than a recolour of it.
The artwork is a snapshot, so the system keeps working if the source layer is trimmed, hidden or deleted. Edit that layer afterwards and the particles stay as they were until you use Update artwork from layer to re-take it. Emit while the layer is on the timeline ties emission to the source clip’s span instead — it is off by default, because the usual recipe picks a layer and then trims the donor away.
The source layer itself stays put — a full dissolve transition, where the layer also disappears as its particles leave, is not part of this yet.
Several layers, one emitter
Stop emitting from this layer removes a source; the row beneath it adds another, up to four. Each source carries its own rect, because two layers do not share one — a word and a mark sit in different places at different sizes, and the emitter’s own Size and Position is only the box the merged result is expressed in.
Sites are shared between the sources by artwork area rather than evenly, so a large shape and a small one both come apart at the same density instead of the small one being over-sampled into a solid blob.
Distribution — how spawn sites are spread
Distribution is orthogonal to the emitter’s geometry: the sampler produces a point in a unit cube and each shape maps it through its own form, so Box, Sphere, Cone, Ring, Path and Block all get every mode. A layer emitter does not use it — its sites are the artwork’s own opaque pixels — and a Point emitter has no extent to spread anything across. Random is the default and is exactly what the emitter has always done, so no saved project moves.
| Mode | What it does |
|---|---|
| Random | Three independent draws — every particle placed knowing nothing about any other, so clumps and holes are not a defect, they are what independence looks like. |
| Stratified | One particle anywhere inside its own cell of a lattice. Keeps the organic look of Random but cannot clump across a cell wall. The drop-in upgrade. |
| Grid (equal) | Exact cell centres. Perfectly regular and perfectly artificial — a dot matrix, a formation, a wall of tiles. |
| Packed | Rows offset by half a cell — hexagonal in plane, tetrahedral through depth. The densest arrangement that is still perfectly even, and the one that reads as a solid surface rather than a grid. |
| Relaxed | Points dropped at random, then pushed off each other until nothing is clumped. Even like a lattice but with no direction and no repeating cell — what “scattered evenly” looks like when nobody is meant to notice the scattering. |
| Low-discrepancy | A quasi-random sequence instead of white noise: looks random, spaces like a lattice, and is even at any count without knowing the total. The one to reach for on a continuously emitting system. |
| Sunflower | The golden angle, 137.5°, one turn per particle — the only way to fill a disc or a sphere perfectly evenly in closed form. It fills centre-outward, which is lovely as a growth and wrong if the shape is meant to be populated all at once. |
| Concentric | Rings evenly spaced by area, each offset from the last so the spokes never line up. Reads as designed rather than scattered: targets, radar, ripples, a dial. |
| Clustered | Cluster seeds scattered first, then every particle born near one of them — clumping as a look. Sparks off an impact, embers, flocks, a debris field. |
| Falloff | Random, but the density is biased along the shape’s radial axis: packed into the core, or hollowed out towards the rim. |
| Shell | The skin only. A sphere becomes a bubble, a disc a rim, a box six faces — every particle at the same depth rather than merely crowding near it. |
Each mode brings its own extra controls where it needs them:
- Spread sites — how many distinct places the pattern has before it repeats. A lattice cannot be built without knowing this, and an emitter never knows how many particles it will ultimately make, so the set is fixed and the next particle lands on the first site again. Auto tracks Max particles, which is the only value at which nothing doubles up.
- Jitter — softens a lattice back towards organic without giving up its coverage. On Low-discrepancy it does something else useful: a per-seed rotation of the whole sequence, so two emitters with the same settings do not spawn in lockstep.
- Fill order — the order a set-based mode walks its own sites in, which only shows itself while the emitter is still filling. Scan is reading order, which fills the emitter one corner at a time on anything that emits over time; Scramble and Shuffle both reach the whole shape immediately.
- Sequence (Low-discrepancy) — R2 is three multiplies and no loop, the cheapest thing that beats white noise; Halton is a shade more even but shows a faint lattice in the first few hundred particles.
- Relax passes (Relaxed) — how many times every point is pushed off its neighbours. Past about fifteen the set has converged and more only costs bake time.
- Rings (Concentric), Clusters and Tightness (Clustered), Bias (Falloff), Skin depth (Shell).
Skin depth is never zero: a mathematically thin surface aliases into a flickering wire as the camera moves.
Where to go next
- Particle Solver — the solver box, presets, look, colour and activation
- Particle Forces, Fluid and Smoke
- Particle Collisions and Packing
- Grow Fill — the arrival sweep Particle Activation borrows
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