Particles
Spawn clouds of points for dust, sparks, debris, sand and snow, and let forces, age and collisions carry them.
Particles are the simplest and most flexible simulation here. Feed in a set of points and Particle Sim moves them every frame under gravity, force fields, and optionally collisions with each other. Because particles are points, millions of them are cheap, and they can be dressed afterwards as sprites, impostors or instanced geometry.
Emitting particles
Particles start as points. Anything that makes points can feed the sim: a Points node filling a surface, an imported point cloud, or a primitive's vertices. Wire those points into the Particle Sim node and they become the live particle set.
To emit continuously over time, drive the point source so it adds new points each frame, then carry the simulation across frames in a feedback loop (see Loops & feedback). Solver state persists between frames, so particles accumulate and age rather than restarting every cook.
Each particle carries attributes you can read and animate, including age, velocity and position. Use these in an Expression to fade, colour or scale particles over their lifetime. See Attributes.
Forces and motion
On its own the Particle Sim applies gravity and integrates motion. To push particles around, wire in a Force Field:
Directional for a steady push, like wind.
Point to pull toward or blast away from a position, an attractor or a repulsor.
Vortex to swirl around an axis.
Turbulence, procedural noise, for drifting motion.
Drag to slow particles down over time.
Each force has a falloff (none, linear, quadratic or smooth) so its influence fades with distance. Forces stack: wind plus turbulence plus a gentle vortex all act at once. See Forces & collisions.
A field can drive particles too. A vector volume baked from curl noise acts as a spatially varying wind. See Fields & sampling.
Self-collision: dust against sand
Self-collision is the switch that changes the character of the whole sim.
Off, particles ignore each other and are purely force-driven. They overlap freely and flow like a gas, which is the look for dust, sparks, smoke wisps and debris.
On, which is the default, particles push apart with contact and friction and behave like a granular material. They pile up, form slopes and settle into heaps, which is sand, snow, gravel and grain. A fresh Particle Sim therefore behaves like sand until you turn the switch off.
Particles also collide with colliders in the scene: a Physics Collider surface, a ground plane, or a Distance Field volume used as a collision boundary. Sand pours onto geometry, sparks bounce off walls.
| Parameter | Type | Default | What it does |
|---|---|---|---|
input | Points or Geometries | — | Point cloud (each point becomes a particle) or geometry to sample |
self_collision | Boolean | true | Particles collide with each other (grains pile up). Off = force-driven particles that pass through one another (dust, sparks) but still hit the ground. |
particle_radius | Number | 0.050 | Particle collision radius |
friction | Number | 0.500 | Inter-particle friction (0 = frictionless ice, 1 = high grip rubber) |
restitution | Number | 0.300 | Restitution / bounciness (0 = dead stop, 1 = fully elastic) |
cohesion | Number | 0 | Cohesion — stickiness between particles (0 = dry sand, 0.5 = wet sand, 1 = snow) |
damping | Number | 0.010 | Velocity damping / air drag (energy loss per frame) |
strength | Number | 1 | Effect strength / wet-dry (0 = no effect, 1 = full). Editable, wirable, keyframable. |
Rendering particles
Particles are points, so they draw as dots until you dress them after the sim.
Sprites, textured points that always face the camera. Cheap and fast, and the usual choice for sparks, dust motes and soft puffs.
Impostors, points holding a continuously re-baked 3D look, so they read as solid even up close.
Instanced geometry, a real shape such as a pebble or a snowflake copied onto every particle.
See Sprites, impostors & billboards and Rasterizing.