Components

An entity is a name and a place in the world. Everything else it is or does comes from its components: a mesh to draw, a light, a body for physics, a sound. Add one with Add component at the bottom of the inspector, and take one off with the ... in its header.

Every picture on this page is the editor with an entity of the test scene selected, so the component is open in the inspector on the right.

Group	Components
Every entity	Transform
Drawing	Camera, Mesh Renderer, Sky
Light	Directional Light, Point Light, Spot Light
Physics	Rigidbody, Box Collider, Sphere Collider, Capsule Collider, Mesh Collider, Joint, Character Controller
Sound	Audio Source, Audio Listener
Animation	Skinned Mesh Renderer, Animator
Effects	Particle System, Text
Screen UI	UI Canvas, UI Element
Code	Scripts

Transform

Every entity has one, and it cannot be removed. It is where the entity is, relative to its parent in the hierarchy, or to the world for an entity at the top.

Field	What it is
Position	Where it is, in units. One unit is about a metre. Y is up
Rotation	How it is turned about each axis, in degrees
Scale	How much it is stretched along each axis. 1 is as made

A child follows its parent's transform. Drag the gizmo in the viewport to change these by hand.

Camera

What the game is seen through. The scene draws from the first camera marked Primary. A camera looks down its entity's -Z axis, with +Y up.

The main camera selected, with what it sees in the corner

Field	What it is
Projection	Perspective, where far things look smaller, or Orthographic, where they do not
Field of view	How wide it sees, top to bottom, in degrees. Perspective only
Size	How tall the view is, in units. Orthographic only
Near clip, Far clip	Nothing nearer or farther than these distances is drawn
Primary	The camera the game is seen through

Mesh renderer

Draws a mesh: a built-in Cube, Sphere or Plane, or a mesh from a model you imported.

The ground selected: a plane with a mesh renderer and a box collider

Field	What it is
Mesh	The shape to draw
Material 0, Material 1...	One material for each part of the mesh. An empty slot draws with the default material

Materials are made in the Assets panel and edited in the inspector.

Sky

An HDR picture of the world all round, drawn behind everything. It also lights the scene: the sky's colours fall on every surface, and shiny things reflect it. The scene uses the first sky it finds, and where its entity stands does not matter.

The sky selected

Field	What it is
Environment	An `.hdr` picture, the kind made to wrap round a sphere. Free ones are on Poly Haven
Intensity	How strongly it lights the scene
Rotation	Turns the sky about the vertical axis, in degrees, to put its sun where you want it

Directional light

Light from far away that falls the same way everywhere, as sunlight does. It shines down its entity's -Z axis, so turning the entity moves the sun.

The sun selected, its rays drawn the way it shines

Field	What it is
Colour	The light's colour
Intensity	How bright. 3 is a bright day
Cast shadows	Whether things block it. Only the first directional light with shadows has them

Point light

Light that shines every way from a point, as a bulb does.

The lamp selected, with a sphere as far as its light reaches

Field	What it is
Colour, Intensity	As for a directional light
Range	How far it reaches. It fades smoothly to nothing there
Cast shadows	Off at first, since a point light's shadow costs six pictures a frame

Spot light

A cone of light down its entity's -Z axis, as a torch or a stage light makes.

The spotlight selected, with its cone drawn

Field	What it is
Colour, Intensity, Range	As for a point light
Inner angle	Inside this cone the light is at full strength, in degrees across
Outer angle	It fades from the inner cone to nothing at this one
Cast shadows	Off at first

A scene can have 16 lights in view at once. Twelve shadow maps are shared by point and spot lights: a spot light takes one and a point light six. More in Lights.

Rigidbody

Makes the entity a physics body. Its shape comes from the collider components on the same entity: without one it has no shape and touches nothing.

A crate with a rigidbody, a box collider and a script

Field	What it is
Type	Static never moves, and others bump into it. Dynamic is moved by gravity and by whatever hits it. Kinematic is moved by its transform, from a script or an animation, and pushes dynamic bodies without being pushed back
Mass	In kilograms. Dynamic bodies only
Friction	0 is ice, 1 is rubber on concrete
Restitution	Bounciness. 0 does not bounce, 1 bounces back to where it fell from
Linear damping, Angular damping	How quickly moving and spinning die away on their own
Gravity scale	How much gravity pulls on it. 0 floats

An entity with a collider and no rigidbody is a static body, which is all a wall or a floor needs. More in Rigid bodies.

Box, sphere and capsule colliders

The shape of a physics body, as a simple solid. Several colliders on one entity make one shape together. Sizes are in the entity's own units and follow its scale.

A coin with a sphere collider that is a trigger

Field	What it is
Size	Box: its full size along each axis
Radius	Sphere and capsule: how round
Height	Capsule: from tip to tip, round ends included. A capsule stands up along Y
Center	Where the shape sits, relative to the entity
Is trigger	A trigger blocks nothing and reports what enters it, to a script's `OnTriggerEnter`. Coins and doorways are triggers

Switch on Colliders over the viewport to see every shape outlined.

Collider outlines on, with a crate selected

Mesh collider

A collider with the shape of a mesh, for something a box or a sphere does not fit.

The pyramid with a mesh collider

Field	What it is
Mesh	The shape. Left empty, it is the mesh the entity's Mesh Renderer draws
Convex	The mesh shrink-wrapped, with every dent filled in. Cheaper, and the only kind a moving body can have
Is trigger	As for the other colliders

Not convex, it is the exact triangles, for level geometry that stays put. A body that moves gets the convex shape whatever this says.

Joint

Ties the entity's body to another body, or to the world. The entity needs a Rigidbody and a collider.

The lantern on a distance joint, hanging from the world

Field	What it is
Type	Fixed welds the two together as they are. Hinge lets them turn about one axis: a door, a wheel. Distance keeps two points within a range of distances: a rod, or a rope
Connected entity	The other body. Empty ties it to the world
Anchor	Where the joint sits, relative to this entity
Connected anchor	Distance only: the point on the other body, or in the world
Axis	Hinge only: the direction it turns about
Min distance, Max distance	Distance only. A negative value means the distance they are at when the game starts

Character controller

Makes the entity a game character: it walks along the ground, climbs steps and gentle slopes, slides along walls and never falls over. Scripts tell it which way to walk and when to jump. Its shape is an upright capsule, and colliders or a Rigidbody on the same entity are not used.

The player with a character controller and its script

Field	What it is
Radius, Height	The capsule's size
Center	Where the capsule sits. With the entity at the character's feet, this is half the height, straight up
Slope limit	The steepest ground it walks up, in degrees
Step height	The tallest ledge it walks up without jumping
Mass	How hard it pushes the dynamic bodies it walks into
Gravity scale	How much gravity pulls on it

Audio source

Plays a sound from where the entity is.

The music, an audio source on the Music bus

Field	What it is
Clip	A `.wav`, `.mp3` or `.flac` file
Bus	Music or Sfx. Each bus has its own volume, set in Project settings
Volume, Pitch	Pitch 2 is an octave up and twice as fast
Loop	Starts again at the end
Play on start	Starts when the scene does. Off, a script starts it
Spatial	Heard from the entity's position, louder when near. Off, it sounds the same everywhere, as music should
Min distance, Max distance	Spatial only: full volume within the first, silent beyond the second
Stream	Read from the file as it plays rather than all at once. For music
Loop start, Loop end	In seconds. A looping sound goes back to the start point when it reaches the end point, so music can play its opening once and repeat the rest

Audio listener

Where spatial sounds are heard from. Without one, it is the primary camera. With several, the first one that is Active listens. More in Audio.

Skinned mesh renderer

Draws a mesh that a skeleton bends, such as a character. Importing an animated model sets this up for you.

Field	What it is
Mesh	The mesh, a part of a model
Skeleton	The bones it is tied to, a part of the same model
Material 0...	As for a mesh renderer

Animator

Moves a skinned mesh: through the states of an animator controller, or by playing one clip round and round.

The arm with a skinned mesh renderer and an animator

Field	What it is
Controller	A `.cairnanimator` file: states, and when to go from one to another
Clip	With no controller, this animation plays on a loop
Speed	How fast everything plays
Playing	Off, it holds the pose it is in

Animation plays in play mode only. More in Animation.

Particle system

Gives off small squares that face the camera, move, fade and die: sparks, smoke, dust, magic.

Sparks: an additive particle system

Field	What it is
Playing	Off, nothing new comes out. What is in the air lives on
Looping	Round and round. Off, it runs for the duration and stops
Duration	The length of one round, in seconds
Rate	Particles per second
Bursts	Many particles at once, at a set time in the round
Max particles	It stops giving off more at this many
Lifetime, Speed	Each particle gets a value between the two given
Direction, Spread	Which way they leave, and how many degrees off it they may go
Radius	They start within this distance of the entity
Gravity	1 falls as things do, 0 floats, below 0 rises
Start colour, End colour	From one at birth to the other at death. Alpha is how solid
Start size, End size	The side of each square, in units
Texture	A picture for each particle. Empty is a soft round dot
Blend	Additive adds light, for fire and sparks. Alpha covers what is behind, for smoke

Smoke: an alpha particle system

Particles move while you edit too, so you can tune a system by eye. More in Particles.

Text

Words in the world, on a flat sheet where the entity stands: a sign, a name over a head.

The sign, words standing in the level

Field	What it is
Text	The words. A new line starts a new line
Size	The height of the letters, in units
Colour	The letters' colour
Font	A `.ttf` font from the project. Empty is the built-in font
Align	Left, centre or right
Face camera	Turns to face the camera always

UI canvas

The top of a piece of screen UI: a menu, a HUD. The UI elements under it in the hierarchy are drawn over the game.

The HUD canvas with its script

Field	What it is
Reference size	The screen size the UI was made for. Everything is scaled evenly to fit the real screen
Visible	Off hides the whole UI

UI element

One piece of screen UI, placed inside its parent: the nearest UI element above it, or the canvas.

The HUD's button

Field	What it is
Type	Panel, image, text, button, slider, toggle or progress bar
Visible	Off hides it and everything under it
Anchor	Where in the parent it is fastened, from (0, 0) at the top left to (1, 1) at the bottom right
Pivot	Which point of itself is fastened there, counted the same way
Position	Moved from there by this much, in reference units. Y is down
Size	Its width and height
Stretch	This share of the parent's size is added to Size. (1, 1) with a size of 0 fills the parent
Colour	The rectangle's colour, or the letters' for text
Texture	A picture, for an image, or behind a panel or a button
Text, Font size, Font, Align	The words of a text, or the label of a button or a toggle
Text colour	A button's or toggle's label, and a slider's handle
Interactable	Off, a control is faded and cannot be used
Value	A slider's or progress bar's value, from 0 to 1
Checked	Whether a toggle is ticked

A script on the element hears about clicks through OnClick and OnValueChanged. More in UI.

Scripts

The Lua or TypeScript files that make the entity do things. An entity can have several, each a section of its own in the inspector with the fields its script exposes. See Inspector for the buttons, and Scripting for writing them.

#Components

#Transform

#Camera

#Mesh renderer

#Sky

#Directional light

#Point light

#Spot light

#Rigidbody

#Box, sphere and capsule colliders

#Mesh collider

#Joint

#Character controller

#Audio source

#Audio listener

#Skinned mesh renderer

#Animator

#Particle system

#Text

#UI canvas

#UI element

#Scripts