Particles

Particles give you fire, smoke, sparks, dust, rain and magic: anything made of many small things moving together. This page shows which settings shape the look.

Each particle starts on a shape, flies under gravity and drag, and fades out over its lifetime. Even a thousand particles cost very little.

Add particles

1. Select an object.
2. In the inspector, click + new component and choose Particles.
3. To start from a ready look, open Preset at the top of the component and pick Fire, Smoke, Sparks, Magic, Snow or Fountain. It replaces the current settings.
4. Adjust the settings described below.

A new emitter already shows something

The default settings are a fire preset. So you see what you are changing right away, not an empty object.

How many, and for how long

In the editor	Field	What it does
Particles	count	how many particles exist at once
life, s	lifetime	how many seconds each particle lives
Emitting	emitting	turns the emitter on and off

These two numbers set how many new particles appear each second: count ÷ lifetime.

• A short lifetime with a high count gives a dense, fast effect.
• A long lifetime with the same count gives a slow, sparse one.

Where particles start

Pick a shape (shape):

Shape	Field	Particles start…
Point	point	all from one spot
Sphere	sphere	anywhere inside the Radius (radius)
Box	box	anywhere inside the Extents (extents)
Cone	cone	in a cone around the object's up axis; Spread angle (angle) sets its width

Spread angle is measured from the centre of the cone to its edge, in degrees. 15 gives a narrow jet, and 180 sprays in every direction.

Cone is the default, because it suits fire, jets, sparks and fountains.

How particles move

In the editor	Field	What it does
Speed min · max	speedMin · speedMax	starting speed, picked between the two
Gravity	gravity	a steady pull: negative Y to fall, positive Y to rise
Motion → drag	drag	how quickly particles slow down
Motion → turb	turbulence	how much they wander; this keeps smoke looking natural
spin	spin	how fast they rotate

Gravity can point any way

The default pulls particles up, which makes fire and smoke rise. Sideways gravity gives you wind-blown rain or spray in a draught.

How particles look

In the editor	Field	What it does
Size start · end	sizeStart · sizeEnd	size when a particle appears and when it disappears
Size jitter	sizeJitter	how much sizes vary between particles
Color	colorStart · colorEnd	colour over the lifetime
Opacity start · end	opacityStart · opacityEnd	fading in and out
Particle sprite	sprite	an image; its transparent parts give each particle its shape
Glow (additive) or Normal blending	blending	additive or normal

Blending decides whether an effect looks like light or like matter.

• Glow (additive) adds up brightness where particles overlap. Use it for fire, sparks, magic and anything that glows.
• Normal blending layers particles like paint. Use it for smoke, dust, rain and debris.

Without a sprite, each particle is a soft circle. That works well for smoke and sparks.

Starting points

These are recipes: settings to try by hand. Fire, smoke and sparks are also in the Preset menu. Dust and rain are not, so build them from the recipe.

Effect	In Preset	Settings to try
Fire	yes	cone, narrow angle, upward gravity, additive, yellow to red, shrinking
Smoke	yes	cone, wide angle, gentle upward gravity, normal blending, grey, growing, fading out
Sparks	yes	point or cone, high speed, downward gravity, additive, tiny, short lifetime
Dust	no	box, speed near zero, no gravity, high turbulence, normal blending, long lifetime
Rain	no	box overhead, downward gravity, high speed, low turbulence

The same look for everyone

The same settings give the same look for every viewer. An emitter adds no cost in a multiplayer scene, and it never gets out of step between people.

Seed (seed) controls the randomness. Change it to get a different arrangement from the same settings. Keep it, and everyone sees the same arrangement.

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Next: Cameras — what your visitor looks through.