API:Class/WeldConstraint

ExplorerImageIndex94.pngWeldConstraint : Object Icon.pngInstance

WeldConstraints are used to attach two parts together. The constraint makes sure that the parts stay in the same relative position and orientation to one another. This means that if one part moves, the other will move the same amount. Even if the two parts are not touching one another, they can be welded together with a WeldConstraint.

Creating WeldConstraints

The most common way to create a WeldConstraint is through the Studio tool. This tool is in the Model tab under the Create dropdown.

CreateWeldConstraint.png

This tool will act differently based on how many parts are selected when the tool is activated.

No Parts Selected

If no parts are selected when the Weld tool is clicked, the next two parts that are clicked on will be welded together. If the same part is clicked twice no weld will be created.

One Part Selected

If one part is selected when the Weld tool is clicked, the next part that is clicked on will be welded to the selected part.

Multiple Parts Selected

If several parts are selected when the Weld tool is clicked, any parts in that selection that are touching or overlapping will be welded together.

Repositioning Welded Parts

The Roblox handles moving a welded part differently depending on whether the part was moved using its Position or with its CFrame. If a welded part’s Position is updated, the part will move but none of the connected parts will move with it. The weld will recalculate the offset from the other part based on the part’s new position.

-- Create two parts and position them at the same height
local partA = Instance.new("Part")
local partB = Instance.new("Part")
partA.Position = Vector3.new(0, 10, 0)
partB.Position = Vector3.new(0, 10, 10)
partA.Parent = game.Workspace
partB.Parent = game.Workspace
 
-- Weld the two parts together
local weld = Instance.new("WeldConstraint")
weld.Parent = game.Workspace
weld.Part0 = partA
weld.Part1 = partB
 
-- Update the position of the first part. The first part
-- will move but the second will stay where it started. The
-- weld maintain the new offset
partA.Position = Vector3.new(0, 20, 0)

If instead a part’s CFrame is updated, then that part will move and any part welded to that part will also move. These other parts will be moved to make sure they maintain the same offset as when the weld was created.

-- Create two parts and position them at the same height
local partA = Instance.new("Part")
local partB = Instance.new("Part")
partA.Position = Vector3.new(0, 10, 0)
partB.Position = Vector3.new(0, 10, 10)
partA.Parent = game.Workspace
partB.Parent = game.Workspace
 
-- Weld the two parts together
local weld = Instance.new("WeldConstraint")
weld.Parent = game.Workspace
weld.Part0 = partA
weld.Part1 = partB
 
-- Update the cframe of the first part. The second part will
-- also move to maintain the offset of the weld.
partA.CFrame = CFrame.new(0, 20, 0)

Properties

PropertiesmemberhiddenProperties [toggle]

boolEnabled

Toggles the constraint on and off.

|RMD member="API:Class/WeldConstraint/Enabled"|Toggles the constraint on and off.|/RMD|
Ref<BasePart>Part0

The first part connected by the constraint.

|RMD member="API:Class/WeldConstraint/Part0"|The first part connected by the constraint.|/RMD|
Ref<BasePart>Part1

The second part connected by the constraint.

|RMD member="API:Class/WeldConstraint/Part1"|The second part connected by the constraint.|/RMD|
Toggles the constraint on and off.
The first part connected by the constraint.
The second part connected by the constraint.
Inherited from Object Icon.pngInstance:
boolArchivable

Determines if an object can be Clone or saved to file.

|RMD member="API:Class/Instance/Archivable"|Determines if an object can be Clone or saved to file.|/RMD|
stringClassName [readonly]

The unique name of this type of Instance.

|RMD member="API:Class/Instance/ClassName"|The unique name of this type of Instance.|/RMD|
stringName

A non-unique identifier for the object.

|RMD member="API:Class/Instance/Name"|A non-unique identifier for the object.|/RMD|
Ref<Instance>Parent

The hierarchical parent of the object.

|RMD member="API:Class/Instance/Parent"|The hierarchical parent of the object.|/RMD|
intDataCost [LocalUserSecurity] [deprecated] [readonly]

Deprecated. Do not use.

|RMD member="API:Class/Instance/DataCost"|Deprecated. Do not use.|/RMD|
boolRobloxLocked [PluginSecurity]

If true, the object and its descendants cannot be indexed or edited by a Script or LocalScript and will throw an error if it is attempted.

|RMD member="API:Class/Instance/RobloxLocked"|If true, the object and its descendants cannot be indexed or edited by a Script or LocalScript and will throw an error if it is attempted.|/RMD|
boolarchivable [deprecated] [hidden]

Deprecated in favor of Archivable.

|RMD member="API:Class/Instance/archivable"|Deprecated in favor of Archivable.|/RMD|
stringclassName [deprecated] [readonly]

Deprecated in favor of ClassName.

|RMD member="API:Class/Instance/className"|Deprecated in favor of ClassName.|/RMD|
Determines if an object can be Clone or saved to file.
ClassName [readonly]
The unique name of this type of Instance.
A non-unique identifier for the object.
The hierarchical parent of the object.
DataCost [LocalUserSecurity] [deprecated] [readonly]
Deprecated. Do not use.
RobloxLocked [PluginSecurity]
If true, the object and its descendants cannot be indexed or edited by a Script or LocalScript and will throw an error if it is attempted.
archivable [deprecated] [hidden]
Deprecated in favor of Archivable.
className [deprecated] [readonly]
Deprecated in favor of ClassName.

Functions

FunctionsmemberhiddenFunctions [toggle]

Inherited from Object Icon.pngInstance:
voidClearAllChildren ( )

Removes all descendants of the object.

|RMD member="API:Class/Instance/ClearAllChildren"|Removes all descendants of the object.|/RMD|
Ref<Instance>Clone ( )

Returns a copy of the object, including descendants, but only if the object is Archivable.

|RMD member="API:Class/Instance/Clone"|Returns a copy of the object, including descendants, but only if the object is Archivable.|/RMD|
voidDestroy ( )

Sets the Parent property to nil, locks the Parent property, disconnects all connections and calls Destroy() on all children.

|RMD member="API:Class/Instance/Destroy"|Sets the Parent property to nil, locks the Parent property, disconnects all connections and calls Destroy() on all children.|/RMD|
Ref<Instance>FindFirstAncestor ( string name )

Returns the first ancestor whose Name is equal to name, or nil if none can be found.

|RMD member="API:Class/Instance/FindFirstAncestor"|Returns the first ancestor whose Name is equal to name, or nil if none can be found.|/RMD|
Ref<Instance>FindFirstAncestorOfClass ( string className )

Returns the first ancestor whose ClassName is equal to className, or nil if none can be found.

|RMD member="API:Class/Instance/FindFirstAncestorOfClass"|Returns the first ancestor whose ClassName is equal to className, or nil if none can be found.|/RMD|
Ref<Instance>FindFirstAncestorWhichIsA ( string className )

Returns the first ancestor that inherits the class className, or nil if none can be found.

|RMD member="API:Class/Instance/FindFirstAncestorWhichIsA"|Returns the first ancestor that inherits the class className, or nil if none can be found.|/RMD|
Ref<Instance>FindFirstChild ( string name, bool recursive = false )

Returns the first child found with the given name, or nil if no such child exists. If the optional recursive argument is true, recursively descends the hierarchy while searching rather than only searching the immediate object.

|RMD member="API:Class/Instance/FindFirstChild"|Returns the first child found with the given name, or nil if no such child exists. If the optional recursive argument is true, recursively descends the hierarchy while searching rather than only searching the immediate object.|/RMD|
Ref<Instance>FindFirstChildOfClass ( string className )

Returns the first Instance whose ClassName is equal to className, or nil, if no such object is found with that ClassName.

|RMD member="API:Class/Instance/FindFirstChildOfClass"|Returns the first Instance whose ClassName is equal to className, or nil, if no such object is found with that ClassName.|/RMD|
Ref<Instance>FindFirstChildWhichIsA ( string className, bool recursive = false )

Returns the first child that inherits the class className, or nil if none can be found.

|RMD member="API:Class/Instance/FindFirstChildWhichIsA"|Returns the first child that inherits the class className, or nil if none can be found.|/RMD|
array<Instance>GetChildren ( )

Returns an array of the object's children.

|RMD member="API:Class/Instance/GetChildren"|Returns an array of the object's children.|/RMD|
array<Instance>GetDescendants ( )

Returns an array containing all of the descendants of the instance.

|RMD member="API:Class/Instance/GetDescendants"|Returns an array containing all of the descendants of the instance.|/RMD|
stringGetFullName ( )

Returns a string which shows the object's ancestry chain.

|RMD member="API:Class/Instance/GetFullName"|Returns a string which shows the object's ancestry chain.|/RMD|
RBXScriptSignalGetPropertyChangedSignal ( string property )

Returns a signal that is fired when the specified property is changed on this object.

|RMD member="API:Class/Instance/GetPropertyChangedSignal"|Returns a signal that is fired when the specified property is changed on this object.|/RMD|
boolIsA ( string className )

Returns true if the object is an instance of the given class, or if the object's class inherits from the given class.

|RMD member="API:Class/Instance/IsA"|Returns true if the object is an instance of the given class, or if the object's class inherits from the given class.|/RMD|
boolIsAncestorOf ( Instance descendant )

Returns true if the object is an ancestor of the given descendant.

|RMD member="API:Class/Instance/IsAncestorOf"|Returns true if the object is an ancestor of the given descendant.|/RMD|
boolIsDescendantOf ( Instance ancestor )

Returns true if the object is a descendant of the given ancestor.

|RMD member="API:Class/Instance/IsDescendantOf"|Returns true if the object is a descendant of the given ancestor.|/RMD|
Ref<Instance>WaitForChild ( string childName, double timeOut )

Yields the current thread until a child with the given name is found, then returns the child. If the timeOut parameter is specified, this function will time out and return nil if timeOut seconds elapse without the child being found.

|RMD member="API:Class/Instance/WaitForChild"|Yields the current thread until a child with the given name is found, then returns the child.

If the timeOut parameter is specified, this function will time out and return nil if timeOut seconds elapse without the child being found.|/RMD|

stringGetDebugId ( int scopeLength = 4 ) [PluginSecurity] [notbrowsable]

Returns a coded string of the object's DebugId used internally by Roblox.

|RMD member="API:Class/Instance/GetDebugId"|Returns a coded string of the object's DebugId used internally by Roblox.|/RMD|
voidRemove ( ) [deprecated]

Deprecated. Do not use.

|RMD member="API:Class/Instance/Remove"|Deprecated. Do not use.|/RMD|
array<Instance>children ( ) [deprecated]

Deprecated in favor of GetChildren.

|RMD member="API:Class/Instance/children"|Deprecated in favor of GetChildren.|/RMD|
Instanceclone ( ) [deprecated]

Deprecated in favor of Clone.

|RMD member="API:Class/Instance/clone"|Deprecated in favor of Clone.|/RMD|
voiddestroy ( ) [deprecated]

Deprecated in favor of Destroy.

|RMD member="API:Class/Instance/destroy"|Deprecated in favor of Destroy.|/RMD|
InstancefindFirstChild ( string name, bool recursive = false ) [deprecated]

Deprecated in favor of FindFirstChild.

|RMD member="API:Class/Instance/findFirstChild"|Deprecated in favor of FindFirstChild.|/RMD|
array<Instance>getChildren ( ) [deprecated]

Deprecated in favor of GetChildren.

|RMD member="API:Class/Instance/getChildren"|Deprecated in favor of GetChildren.|/RMD|
boolisA ( string className ) [deprecated]

Deprecated in favor of IsA.

|RMD member="API:Class/Instance/isA"|Deprecated in favor of IsA.|/RMD|
boolisDescendantOf ( Instance ancestor ) [deprecated]

Deprecated in favor of IsDescendantOf.

|RMD member="API:Class/Instance/isDescendantOf"|Deprecated in favor of IsDescendantOf.|/RMD|
voidremove ( ) [deprecated]

Deprecated in favor of Remove.

|RMD member="API:Class/Instance/remove"|Deprecated in favor of Remove.|/RMD|
Removes all descendants of the object.
Clone ( )
Returns a copy of the object, including descendants, but only if the object is Archivable.
Sets the Parent property to nil, locks the Parent property, disconnects all connections and calls Destroy() on all children.
Returns the first ancestor whose Name is equal to name, or nil if none can be found.
Returns the first ancestor whose ClassName is equal to className, or nil if none can be found.
Returns the first ancestor that inherits the class className, or nil if none can be found.
FindFirstChild ( string name, bool recursive = false )
Returns the first child found with the given name, or nil if no such child exists. If the optional recursive argument is true, recursively descends the hierarchy while searching rather than only searching the immediate object.
Returns the first Instance whose ClassName is equal to className, or nil, if no such object is found with that ClassName.
FindFirstChildWhichIsA ( string className, bool recursive = false )
Returns the first child that inherits the class className, or nil if none can be found.
Returns an array of the object's children.
Returns an array containing all of the descendants of the instance.
Returns a string which shows the object's ancestry chain.
Returns a signal that is fired when the specified property is changed on this object.
IsA ( string className )
Returns true if the object is an instance of the given class, or if the object's class inherits from the given class.
IsAncestorOf ( Instance descendant )
Returns true if the object is an ancestor of the given descendant.
Returns true if the object is a descendant of the given ancestor.
WaitForChild ( string childName, double timeOut )
Yields the current thread until a child with the given name is found, then returns the child. If the timeOut parameter is specified, this function will time out and return nil if timeOut seconds elapse without the child being found.
GetDebugId ( int scopeLength = 4 ) [PluginSecurity] [notbrowsable]
Returns a coded string of the object's DebugId used internally by Roblox.
Remove ( ) [deprecated]
Deprecated. Do not use.
children ( ) [deprecated]
Deprecated in favor of GetChildren.
clone ( ) [deprecated]
Deprecated in favor of Clone.
destroy ( ) [deprecated]
Deprecated in favor of Destroy.
findFirstChild ( string name, bool recursive = false ) [deprecated]
Deprecated in favor of FindFirstChild.
getChildren ( ) [deprecated]
Deprecated in favor of GetChildren.
isA ( string className ) [deprecated]
Deprecated in favor of IsA.
isDescendantOf ( Instance ancestor ) [deprecated]
Deprecated in favor of IsDescendantOf.
remove ( ) [deprecated]
Deprecated in favor of Remove.


Events

EventsmemberhiddenEvents [toggle]

Inherited from Object Icon.pngInstance:
AncestryChanged ( Instance child, Instance parent )

Fires when the Parent property of the object or one of its ancestors is changed.

|RMD member="API:Class/Instance/AncestryChanged"|Fires when the Parent property of the object or one of its ancestors is changed.|/RMD|
Changed ( string property )

Fires after a property of the object changes.

|RMD member="API:Class/Instance/Changed"|Fires after a property of the object changes.|/RMD|
ChildAdded ( Instance child )

Fires when a child is added to the object.

|RMD member="API:Class/Instance/ChildAdded"|Fires when a child is added to the object.|/RMD|
ChildRemoved ( Instance child )

Fires when a child is removed from the object.

|RMD member="API:Class/Instance/ChildRemoved"|Fires when a child is removed from the object.|/RMD|
DescendantAdded ( Instance descendant )

Fires when a descendant is added to the object.

|RMD member="API:Class/Instance/DescendantAdded"|Fires when a descendant is added to the object.|/RMD|
DescendantRemoving ( Instance descendant )

Fires before a descendant of the object is removed.

|RMD member="API:Class/Instance/DescendantRemoving"|Fires before a descendant of the object is removed.|/RMD|
childAdded ( Instance child ) [deprecated]

Deprecated in favor of ChildAdded.

|RMD member="API:Class/Instance/childAdded"|Deprecated in favor of ChildAdded.|/RMD|
Fires when the Parent property of the object or one of its ancestors is changed.
Changed ( string property )
Fires after a property of the object changes.
Fires when a child is added to the object.
Fires when a child is removed from the object.
DescendantAdded ( Instance descendant )
Fires when a descendant is added to the object.
Fires before a descendant of the object is removed.
childAdded ( Instance child ) [deprecated]
Deprecated in favor of ChildAdded.
|RMD member="API:Class/WeldConstraint"|WeldConstraints are used to attach two parts together. The constraint makes sure that the parts stay in the same relative position and orientation to one another. This means that if one part moves, the other will move the same amount. Even if the two parts are not touching one another, they can be welded together with a WeldConstraint. ==Creating WeldConstraints== The most common way to create a WeldConstraint is through the Studio tool. This tool is in the Model tab under the Create dropdown. CreateWeldConstraint.png This tool will act differently based on how many parts are selected when the tool is activated. ===No Parts Selected=== If no parts are selected when the Weld tool is clicked, the next two parts that are clicked on will be welded together. If the same part is clicked twice no weld will be created. ===One Part Selected=== If one part is selected when the Weld tool is clicked, the next part that is clicked on will be welded to the selected part. ===Multiple Parts Selected=== If several parts are selected when the Weld tool is clicked, any parts in that selection that are touching or overlapping will be welded together. ==Repositioning Welded Parts== The Roblox handles moving a welded part differently depending on whether the part was moved using its Position or with its CFrame. If a welded part’s Position is updated, the part will move but none of the connected parts will move with it. The weld will recalculate the offset from the other part based on the part’s new position.
-- Create two parts and position them at the same height
local partA = Instance.new("Part")
local partB = Instance.new("Part")
partA.Position = Vector3.new(0, 10, 0)
partB.Position = Vector3.new(0, 10, 10)
partA.Parent = game.Workspace
partB.Parent = game.Workspace
 
-- Weld the two parts together
local weld = Instance.new("WeldConstraint")
weld.Parent = game.Workspace
weld.Part0 = partA
weld.Part1 = partB
 
-- Update the position of the first part. The first part
-- will move but the second will stay where it started. The
-- weld maintain the new offset
partA.Position = Vector3.new(0, 20, 0)
If instead a part’s CFrame is updated, then that part will move and any part welded to that part will also move. These other parts will be moved to make sure they maintain the same offset as when the weld was created.
-- Create two parts and position them at the same height

local partA = Instance.new("Part") local partB = Instance.new("Part") partA.Position = Vector3.new(0, 10, 0) partB.Position = Vector3.new(0, 10, 10) partA.Parent = game.Workspace partB.Parent = game.Workspace   -- Weld the two parts together local weld = Instance.new("WeldConstraint") weld.Parent = game.Workspace weld.Part0 = partA weld.Part1 = partB   -- Update the cframe of the first part. The second part will -- also move to maintain the offset of the weld.

partA.CFrame = CFrame.new(0, 20, 0)
|/RMD|