Instance

The base of every object, with Instance.new to create them.

Every object in a place is an Instance: parts, scripts, folders, interface objects, and the services themselves. Each one has a class name, a name, a place in the tree, and the members its class adds on top of the ones listed here.

Creating one

Call	Returns
`Instance.new(className)`	A new object of that class, with no parent.
`Instance.new(className, parent)`	The same, already parented.

The class name must be one the engine can build on demand:

Group	Names
Parts and models	Part, MeshPart, Model, Folder, Kit
Scripts	Script, LocalScript, ModuleScript
Players and input	Player, InputObject
Networking	RemoteEvent, RemoteFunction
Characters	Humanoid
Interface	ScreenGui, Frame, TextLabel, TextButton, TextBox, ScrollingFrame, ImageLabel, UICorner, UIStroke, UIGradient
Lights	PointLight, SpotLight, SurfaceLight
Animation	Tween

An unknown name raises NotAClass is not a valid class name. Workspace is created with the place and cannot be built again, so Instance.new("Workspace") raises it too.

Members every Instance has

Member	Type	What it does
Name	string	The name shown in the Explorer, used by child lookup and by `FindFirstChild`.
ClassName	string	The class name, read-only.
Parent	Instance or nil	Where the object sits. Setting it moves the object and everything under it.

Reading a member that is not a property, event, or method with an object's name returns its direct child with that exact name, case-sensitive:

local door = workspace.Door          -- same as workspace:FindFirstChild("Door")

A property, event, or method always wins over a child with the same name.

Setting Parent to nil removes the object from the tree. Moving an object into its own descendant raises an error, and so does parenting anything other than a service directly under game.

Events

Every class has these:

Event	Callback arguments	When it fires
ChildAdded	child	A child was parented in.
ChildRemoved	child	A child was parented out.
DescendantAdded	descendant	Anything below this object was added.
DescendantRemoving	descendant	Anything below this object is about to leave.
AncestryChanged	child, parent	This object or a descendant changed parent. `parent` is nil when it left the tree.
Changed	propertyName	A property was written. One write can fire more than one name, such as `CFrame`, `Position`, and `Orientation` for one position change.
Destroying	none	The object is about to be destroyed.

Signals

Connect runs a function every time the signal fires. Once runs it once and then disconnects. Wait pauses the script until the signal fires and returns the arguments the signal sends.

local connection = part.ChildAdded:Connect(function (child)
    print("added", child.Name)
end)

connection:Disconnect()

Signal member	Returns	What it does
Connect(fn)	Connection	Calls `fn` each time the signal fires.
Once(fn)	Connection	Calls `fn` once, then disconnects.
Wait()	the signal's arguments	Yields until the signal fires.

Connection member	Type	What it does
Connected	boolean	True until the connection is disconnected.
Disconnect()	nothing	Stops the callback. Calling it twice is safe.

Connect, Once, Wait, and Disconnect also have lowercase aliases.

Methods

Every instance sees every method. A method only works on the class it belongs to, and calling it on the wrong one raises an error such as GetPlayers is only available on Players.

Method	Works on	What it does
FindFirstChild(name, recursive?)	any	Returns the first child with that name, or a descendant when `recursive` is truthy.
FindFirstChildOfClass(className)	any	Returns the first direct child of that class.
FindFirstChildWhichIsA(className, recursive?)	any	The same lookup as `FindFirstChildOfClass` here; both accept a base class name.
FindFirstAncestor(name)	any	Walks up the tree to the first ancestor with that name.
FindFirstAncestorOfClass(className)	any	Walks up to the first ancestor of that class.
WaitForChild(name, timeout?)	any	Yields until a child with that name exists. Returns nil if the timeout passes first. Without a timeout it waits forever.
GetChildren()	any	A new array of direct children.
GetDescendants()	any	A new array of everything below this object.
GetFullName()	any	The path, such as `Workspace.Door.Hinge`.
IsA(className)	any	Whether the class is that name or derives from it.
IsDescendantOf(ancestor)	any	Whether this object sits anywhere below another.
IsAncestorOf(descendant)	any	The reverse of `IsDescendantOf`.
Destroy()	any	Removes the object and everything under it, and disconnects their signals.
Clone()	any	A deep copy with no parent, or nil for classes that cannot be built on demand.
ClearAllChildren()	any	Destroys every direct child.
GetService(name)	game	Returns a service. See game.
IsServer()	RunService	True on the server.
IsClient()	RunService	True on a client.
IsStudio()	RunService	True when the place is running inside Studio.
BindToRenderStep(name, priority, fn)	RunService	Calls `fn` each rendered frame on the client. Binding the same name again replaces it.
UnbindFromRenderStep(name)	RunService	Removes a binding made with that name.
Build(name)	Kits	Clones the named Kit into Workspace.
GetPlayers()	Players	An array of the players in the game.
SetCoreGuiEnabled(type, enabled)	StarterGui	Shows or hides one of the engine's own interface elements.
GetCoreGuiEnabled(type)	StarterGui	Whether that element is enabled.
FireServer(...)	RemoteEvent	Sends values from a client to the server.
FireClient(player, ...)	RemoteEvent	Sends values from the server to one player.
FireAllClients(...)	RemoteEvent	Sends values from the server to every player.
InvokeServer(...)	RemoteFunction	Calls the server and waits for its return values.
Raycast(origin, direction, maxDistance?, params?)	Workspace	Returns the first thing hit along a ray as a table with `Instance`, `Position`, `Normal`, and `Distance`, or `nil` when nothing is in range.
Explode(center, radius, power, options?)	Physics	Pushes bodies away from a blast. See Physics.
GetMouseLocation()	UserInputService	The mouse position in pixels.
GetMouseDelta()	UserInputService	How far the mouse moved.
IsKeyDown(keyCode)	UserInputService	Whether a key is held.
IsMouseButtonPressed(button)	UserInputService	Whether a mouse button is held.
Create(instance, info, properties)	TweenService	Builds a tween.
Play()	Tween	Starts or resumes the tween.
Pause()	Tween	Holds the tween where it is.
Cancel()	Tween	Stops the tween and leaves the property where it stopped.
GetSunDirection()	Lighting	The direction the sun shines from.
GetMoonDirection()	Lighting	The direction the moon shines from.
Get(key)	Store	Reads a saved value, on the server.
Set(key, value)	Store	Writes a saved value, on the server.
Report()	Perf	Writes timing lines to the Output.

Example

local folder = Instance.new("Folder")
folder.Name = "Loot"
folder.Parent = workspace

local part = Instance.new("Part", folder)
part.Position = Vector3.new(0, 5, 0)

part.ChildAdded:Connect(function (child)
    print("added", child.Name)
end)

print(part:GetFullName())    -- Workspace.Loot.Part