Source: Roblox Creator Hub · CC BY 4.0 · View source · Code samples: MIT Imported 2026-10-03. Formatting adapted for this site.
Selection
Inherits from: Instance → Object
The Selection service controls the Instances that are selected in Roblox Studio.
This service is particularly useful when developing Plugins, as it allows the developer to access and manipulate the current selection.
Currently selected Instances can be obtained and set using the Selection:Get() and Selection:Set() functions. The Selection.SelectionChanged event fires whenever the current selection changes.
For more information on using Selection and Plugins, see Plugin.
Selection is also often used in the command bar, to set hidden properties or run functions for selected Instances.
Note this class only applies to Roblox Studio and has no applicability to games.
Inherits from: Instance
Memory category: Instances
Tags: NotCreatable, Service
Code samples: View on Creator Hub (Selection1).
Properties
| Name | Type / Returns | Description |
|---|---|---|
| Selection.SelectionThickness | float | The thickness of the selection highlight outline drawn around selected Instances in Roblox Studio's viewport. |
Inherited from Instance
| Name | Type / Returns | Description |
|---|---|---|
| Instance.Archivable | boolean | Determines if an Instance and its descendants can be cloned using Instance:Clone(), and can be saved/published. |
| Instance.archivable | boolean | |
| Instance.Capabilities | SecurityCapabilities | The set of capabilities allowed to be used for scripts inside this container. |
| Instance.IsInSandbox | boolean | Indicates whether the instance is inside a sandboxed container. |
| Instance.Name | string | A non-unique identifier of the Instance. |
| Instance.Parent | Instance | Determines the hierarchical parent of the Instance. |
| Instance.PredictionMode | PredictionMode | Reflects the client-side prediction mode applied to the instance under server-authoritative physics. |
| Instance.RobloxLocked | boolean | A deprecated property that used to protect CoreGui objects. |
| Instance.Sandboxed | boolean | When enabled, the instance can only access abilities in its Capabilities list. |
| Instance.UniqueId | UniqueId | A unique identifier for the instance. |
Inherited from Object
| Name | Type / Returns | Description |
|---|---|---|
| Object.ClassName | string | A read-only string representing the class this Object belongs to. |
| Object.className | string |
Selection.SelectionThickness
The thickness of the selection highlight outline drawn around selected Instances in Roblox Studio's viewport.
This read-only property returns the current outline thickness as a float. The default value is 0.02. The value is controlled by Roblox Studio and cannot be changed through the scripting API.
This property can be read in Plugins to query the current selection visualization setting, such as when drawing custom overlays that need to match the built-in selection appearance.
| Field | Value |
|---|---|
| type | float |
| tags | ["ReadOnly","NotReplicated"] |
| security | {"read":"None","write":"None"} |
| thread safety | ReadSafe |
| category | Appearance |
| serialization | {"can_load":false,"can_save":false} |
| capabilities | ["Basic"] |
Methods
| Name | Type / Returns | Description |
|---|---|---|
| Selection:Add | () | Adds the given Instances to the current selection in Roblox Studio. |
| Selection:Get | Instances | Returns an array of currently selected Instances in Roblox Studio. |
| Selection:Remove | () | Removes the given Instances from the current selection in Roblox Studio. |
| Selection:Set | () | Sets the currently selected objects in Roblox Studio to Instances in the given array. |
Inherited from Instance
| Name | Type / Returns | Description |
|---|---|---|
| Instance:AddTag | () | Applies a tag to the instance. |
| Instance:children | Instances | Returns an array of the object's children. |
| Instance:ClearAllChildren | () | This method destroys all of an instance's children. |
| Instance:Clone | Instance | Create a copy of an instance and all its descendants, ignoring instances that are not Archivable. |
| Instance:clone | Instance | |
| Instance:Destroy | () | Sets the Instance.Parent property to nil, locks the Instance.Parent property, disconnects all connections, and calls Destroy() on all children. |
| Instance:destroy | () | |
| Instance:FindFirstAncestor | Instance? | Returns the first ancestor of the Instance whose Instance.Name is equal to the given name. |
| Instance:FindFirstAncestorOfClass | Instance? | Returns the first ancestor of the Instance whose Object.ClassName is equal to the given className. |
| Instance:FindFirstAncestorWhichIsA | Instance? | Returns the first ancestor of the Instance for whom Object:IsA() returns true for the given className. |
| Instance:FindFirstChild | Instance? | Returns the first child of the Instance found with the given name. |
| Instance:findFirstChild | Instance | |
| Instance:FindFirstChildOfClass | Instance? | Returns the first child of the Instance whose ClassName is equal to the given class name. |
| Instance:FindFirstChildWhichIsA | Instance? | Returns the first child of the Instance for whom Object:IsA() returns true for the given className. |
| Instance:FindFirstDescendant | Instance? | Returns the first descendant found with the given Instance.Name. |
| Instance:GetActor | Actor? | Returns the Actor associated with the Instance, if any. |
| Instance:GetAttribute | Variant | Returns the value which has been assigned to the given attribute name. |
| Instance:GetAttributeChangedSignal | RBXScriptSignal | Returns an event that fires when the given attribute changes. |
| Instance:GetAttributes | Dictionary | Returns a dictionary of the instance's attributes. |
| Instance:GetChildren | Instances | Returns an array containing all of the instance's children. |
| Instance:getChildren | Instances | |
| Instance:GetDebugId | string | Returns a coded string of the debug ID used internally by Roblox. |
| Instance:GetDescendants | Instances | Returns an array containing all of the descendants of the instance. |
| Instance:GetFullName | string | Returns a string describing the instance's ancestry. |
| Instance:GetStyled | Variant | Returns the styled or explicitly modified value of the specified property, or else the default property value if it hasn't been styled/modified. |
| Instance:GetStyledPropertyChangedSignal | RBXScriptSignal | Returns an event that fires when the given style property changes on the instance. |
| Instance:GetTags | Array | Gets an array of all tags applied to the instance. |
| Instance:HasTag | boolean | Check whether the instance has a given tag. |
| Instance:IsAncestorOf | boolean | Returns true if an Instance is an ancestor of the given descendant. |
| Instance:IsDescendantOf | boolean | Returns true if an Instance is a descendant of the given ancestor. |
| Instance:isDescendantOf | boolean | |
| Instance:IsPropertyModified | boolean | Returns true if the value stored in the specified property is not equal to the code-instantiated default. |
| Instance:QueryDescendants | Instances | Returns an array containing all descendants of the instance that match the selector string. |
| Instance:Remove | () | Sets the object's Parent to nil, and does the same for all its descendants. |
| Instance:remove | () | |
| Instance:RemoveTag | () | Removes a tag from the instance. |
| Instance:ResetPropertyToDefault | () | Resets a property to its default value. |
| Instance:SetAttribute | () | Sets the attribute with the given name to the given value. |
| Instance:WaitForChild | Instance | Returns the child of the Instance with the given name. If the child does not exist, it will yield the current thread until it does. |
Inherited from Object
| Name | Type / Returns | Description |
|---|---|---|
| Object:GetPropertyChangedSignal | RBXScriptSignal | Get an event that fires when a given property of the object changes. |
| Object:IsA | boolean | Returns true if an object's class matches or inherits from a given class. |
| Object:isA | boolean |
Selection:Add
Adds the Instances in the given array to the current selection. Instances that are already selected remain selected.
Calling this function fires the Selection.SelectionChanged event if any new Instances are added to the selection.
Note this function can only be used in Plugins or the command bar. For setting the selection to an entirely new set of instances, see Selection:Set(). For removing instances from the current selection, see Selection:Remove().
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| instancesToAdd | Instances | An array of Instances to add to the current selection. |
Returns
| Type | Description |
|---|---|
| () |
| Field | Value |
|---|---|
| security | PluginSecurity |
| thread safety | Unsafe |
| capabilities | ["Basic"] |
Selection:Get
Returns an array of currently selected Instances in Roblox Studio.
If no Instances are selected, the array returned will be empty. This function can be used in conjunction with the Selection.SelectionChanged event to get the selection whenever it changes.
Note, this function can only be used in Plugins or the command line.
For changing the current selection, please see Selection:Set().
Returns
| Type | Description |
|---|---|
| Instances | An array of currently selected Instances. |
| Field | Value |
|---|---|
| security | PluginSecurity |
| thread safety | Unsafe |
| capabilities | ["Basic"] |
Code samples: View on Creator Hub (Selection1, Selection-SelectionChanged1).
Selection:Remove
Removes the Instances in the given array from the current selection. Instances that are not currently selected are ignored.
Calling this function fires the Selection.SelectionChanged event if any Instances are removed from the selection.
Note this function can only be used in Plugins or the command bar. For adding instances to the current selection, see Selection:Add(). For replacing the selection entirely, see Selection:Set().
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| instancesToRemove | Instances | An array of Instances to remove from the current selection. |
Returns
| Type | Description |
|---|---|
| () |
| Field | Value |
|---|---|
| security | PluginSecurity |
| thread safety | Unsafe |
| capabilities | ["Basic"] |
Selection:Set
Sets the currently selected objects in Roblox Studio to Instances in the given array.
Calling this function will cause the Selection.SelectionChanged event to fire, unless the new selection set is identical to the previous selection.
Note this function overwrites the existing selection. However, using Selection:Get() an Instance can be added to the existing selection like so:
Parameters
| Name | Type | Default | Description |
|---|---|---|---|
| selection | Instances | An array of Instances to set the current selection to. |
Returns
| Type | Description |
|---|---|
| () |
| Field | Value |
|---|---|
| security | PluginSecurity |
| thread safety | Unsafe |
| capabilities | ["Basic"] |
Code samples: View on Creator Hub (SelectionSet1, Selection-Set).
Events
| Name | Type / Returns | Description |
|---|---|---|
| Selection.SelectionChanged | Fires when the Instances selected in Roblox Studio changes. |
Inherited from Instance
| Name | Type / Returns | Description |
|---|---|---|
| Instance.AncestryChanged | Fires when the Instance.Parent property of this object or one of its ancestors is changed. | |
| Instance.AttributeChanged | Fires whenever an attribute is changed on the Instance. | |
| Instance.ChildAdded | Fires after an object is parented to this Instance. | |
| Instance.childAdded | ||
| Instance.ChildRemoved | Fires after a child is removed from this Instance. | |
| Instance.DescendantAdded | Fires after a descendant is added to the Instance. | |
| Instance.DescendantRemoving | Fires immediately before a descendant of the Instance is removed. | |
| Instance.Destroying | Fires immediately before (or is deferred until after) the instance is destroyed via Instance:Destroy(). | |
| Instance.StyledPropertiesChanged | Fires whenever any style property is changed on the instance, including when a property is set to nil. |
Inherited from Object
| Name | Type / Returns | Description |
|---|---|---|
| Object.Changed | Fires immediately after a property of the object changes, with some limitations. |
Selection.SelectionChanged
Fires when the Instances selected in Roblox Studio changes.
Note this event does not give the new selection. Developers will need to use the Selection:Get() function to obtain the current selection.
Although this event can be used outside of plugins and the command bar, it only applies to the selection in Roblox Studio and therefore has no functionality outside of Studio.
To change the selection use the Selection:Set() function.
| Field | Value |
|---|---|
| security | None |
| capabilities | ["Basic"] |
Code samples: View on Creator Hub (Selection-SelectionChanged1).