32. Instances and the Explorer

Chapter 31 showed that a Roblox experience is a tree of Instances. This chapter zooms in: what an Instance is, how to see it in the Explorer, and how to make and change one from code -- all in a Studio Script.

The Explorer is the tree

Open Studio with the Baseplate template. The Explorer panel (top right) shows the experience as an expandable tree:

game
 ├─ Workspace
 │   ├─ Baseplate
 │   └─ SpawnLocation
 ├─ Players
 ├─ ServerScriptService
 └─ ... more services

Every line is an Instance: a Part, Folder, Script, or service. Each has a ClassName (its kind, like Part), a Name shown in the Explorer, properties, and a Parent -- the Instance it lives inside.

Making an Instance from code

Instance.new("ClassName") creates an Instance. It is not in the world yet -- it sits alone until you give it a parent:

local part = Instance.new("Part")
part.Name = "Platform"
part.Size = Vector3.new(8, 1, 8)
part.Position = Vector3.new(0, 5, 0)
part.Anchored = true
part.Parent = workspace

Make a Part, set its name, size, and position, anchor it against gravity, then place it in workspace. Setting Parent makes it appear in the world and the Explorer.

Vector3.new(x, y, z) is a 3D value for sizes and positions: x is left/right, y up/down, z forward/back.

Set the properties before Parent. Once parented a Part is live; setting size and colour first avoids a flicker where it looks wrong.

Properties worth knowing

A Part has many properties. The ones you reach for first:

Property What it controls
Name The label in the Explorer.
Size A Vector3 — how big it is.
Position A Vector3 — where its centre is.
Anchored true = ignores gravity and stays put.
BrickColor Its colour, e.g. BrickColor.new("Bright red").
Transparency 0 = solid, 1 = invisible.
CanCollide true = solid to players; false = walk through. 
part.BrickColor = BrickColor.new("Bright yellow")
part.Transparency = 0
part.CanCollide = true

Walking the tree from code

Find Instances the way you read the Explorer -- walk down from game or workspace:

  • workspace.Platform -- the child named Platform (errors if missing).
  • workspace:FindFirstChild("Platform") -- the same, but returns nil when missing instead of erroring -- safer to test with if.
  • instance:GetChildren() -- a list of direct children, to loop over with ipairs.
  • instance:Destroy() -- removes an Instance for good.
  • instance:Clone() -- makes a copy you can re-parent.
local coin = workspace:FindFirstChild("Coin")
if coin then
    coin:Destroy()
end

These use the colon because they are methods on the Instance -- the obj:method() form from Chapter 26.

Homework

These do not run in a terminal. Treat them as written exercises: write the code, then check the solutions page. To test for real, paste each into a Script under ServerScriptService and Play.

Problem 1 — Build a platform

Open exercises/32/homework/01-platform.lua. Create an anchored Part named Platform, size 10, 1, 10, at 0, 8, 0, coloured Bright green, parented to workspace.

Problem 2 — Set the properties in order

Open exercises/32/homework/02-order.lua. The snippet sets Parent first, size and colour after. Reorder so every property is set before Parent, and add a one-line comment explaining why.

Problem 3 — Safe find

Open exercises/32/homework/03-safe-find.lua. Using FindFirstChild and an if, destroy a Part named OldWall in workspace only if it exists; otherwise print nothing to remove.

Challenge — A row of pillars

Open exercises/32/homework/04-pillars.lua. Using a for loop, create five anchored pillars (tall thin Parts) in a row, a few studs apart along the x axis. Set each pillar's Position from the loop counter.

Stuck or finished? Open the homework solutions page.