Notes by Lex Toumbourou

An Attachment in Roblox is an object that describes a point and orientation in space relative BasePart's Roblox CFrame.

Consider a Fire that you want to burn from the back of a Part. If I attach a Fire instance directly to a Part, it will always burn from the Part's center of the Part. Instead, I can create an Attachment parented to the Part and position it -2 studs along the X-axis and one stud along the Y-axis from the Part's center.

The Attachment remains in the same place relative to the Part as the part moves.

Here's how it looks in code:

--!strict

-- Create Part.
local part: Part = Instance.new('Part')
part.Anchored = true

-- Create an Attachment behind the Part.
local attachment: Attachment = Instance.new('Attachment')
attachment.Position = Vector3.new(-2, 1, 0)
attachment.Parent = part

-- Attach fire to Attachment instead of Part.
local fire: Fire = Instance.new('Fire')
fire.Size = 1
fire.Heat = 1
fire.Parent = attachment

part.Parent = game.Workspace

-- Code to move Part around below.

A new attachment can be created using Instance.new('Attachment').

An attachment's position can be updated using the Position attribute or editing the CFrame attribute.

There are many items that you can parent directly to an Attachment instead of a Part:

• Any ParticleEmitters can be parented directly to an Attachment.
• Sound objects allow audio to play directly from the Attachment's location.
• PointLight and SpotLight allow light to shine from a specific point on a Part.

Roblox Constraint objects rely on Attachments.

The Roblox Accessory system utilizes attachments to position accessories on a character's body parts.