In-Game Solid Modeling

5 min

Detailed Articles/3D Modeling with Parts|solid models can be created using the Union and Negate tools, not only in Studio but also while your game is being played. This can be used to create some truly unique game concepts.

Solid Modeling APIs

UnionAsync()

The BasePart/UnionAsync|UnionAsync() function must be called on a BasePart. It requires an array of one or more parts (otherParts) to union with the calling BasePart.

			
				Expected Output
			
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			local part = workspace.Part1
local otherParts = {workspace.Part2, workspace.Part3, workspace.Part4}

-- Perform union operation
local newUnion = part:UnionAsync(otherParts)
		
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SubtractAsync()

The BasePart/SubtractAsync|SubtractAsync() function also requires an array of one or more parts to subtract from the calling BasePart.

			
				Expected Output
			
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			local part = workspace.Part1
local otherParts = {workspace.Part2, workspace.Part3, workspace.Part4}

-- Perform union operation
local newUnion = part:SubtractAsync(otherParts)
		
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In-game solid modeling is an asynchronous operation, meaning it can be somewhat expensive. For best in-game performance, you should not perform a lot of these API calls at once.

The following properties from the calling part will be applied to the resulting part:

Color
Material
Reflectance
Transparency

Anchored
CanCollide
Density
Friction

Elasticity
FrictionWeight
ElasticityWeight

Basic Demonstration

Let’s test out in-game solid modeling with a quick demo script! You can copy and paste this into a Script within ServerScriptService, or wherever is most convenient.

Solid modeling APIs only work on the server side (they will not work in a LocalScript).

			
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			-- Create a basic window part
local window = Instance.new("Part")
window.Size = Vector3.new(10, 16, 0.5)
window.Material = "Glass"
window.BrickColor = BrickColor.new("Persimmon")
window.Reflectance = 0.2
window.Transparency = 0.5
window.Position = Vector3.new(0, 8, 0)
window.Anchored = true
window.Parent = game.Workspace

-- Create a part to subtract from window
local subBlock = Instance.new("Part")
subBlock.Size = Vector3.new(4, 4, 4)
subBlock.Material = "SmoothPlastic"
subBlock.CanCollide = false
subBlock.Position = Vector3.new(0, 8, 0)
subBlock.Anchored = true
subBlock.Parent = game.Workspace

wait(2)

-- Subtract smaller block from window
local success, newUnion = pcall(function()
	return window:SubtractAsync({subBlock})
end)

if success and newUnion then
	newUnion.Position = window.Position
	newUnion.Anchored = true
	newUnion.Parent = game.Workspace
	-- Remove original parts
	window:Destroy()
	subBlock:Destroy()
end
		
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In this script, a basic order of operations occurs:

A red glass window is created in the center of the place (lines 2-10).
A smaller block is created in the center of the window part (lines 13-19).
After 2 seconds, BasePart/SubtractAsync|SubtractAsync() is called on the window, using the smaller block as the part to subtract.

There are a few reasons why an in-game solid modeling operation may fail (see the API docs). Because of this, you should always use pcall() to catch any unexpected errors.

If successful, the resulting part is returned with a name of Union. This instance will not be parented to the workspace, so it’s your job to parent it back into the game world.

The original parts remain in the game, including both the instance that the operation is called on (window) and the parts that are added to or subtracted from it (subBlock). As a result, these parts are explicitly destroyed following a successful modeling operation (lines 33-34).

Solid Modeling Playground

Now that you understand basic in-game solid modeling, experience it within a sample place.

Rotating Windows

Blast pieces out of rotating windows or fuse new material onto them. Includes a helper module script that rebuilds mechanisms with constraints and attachments!

Tags:

model
parts
union
negate

In-Game Solid Modeling

In-Game Solid Modeling

Solid Modeling APIs

UnionAsync()

SubtractAsync()

Basic Demonstration

Solid Modeling Playground

Rotating Windows

Related Articles

Solid Modeling – 3D Modeling With Parts