UActorComponent

class Engine Blueprint Since 1.0

Inherits: UObjectBase › UObjectBaseUtility › UObject › UActorComponent

#include "Components/ActorComponent.h"

Access: public Specifiers: UCLASS

Description

The base class for all actor components. Components are reusable pieces of functionality that can be attached to actors. UActorComponent is the lightest component type — it has no transform. Use USceneComponent for components that need world location/rotation.

Caveats & Gotchas

• UActorComponent has no transform. Use USceneComponent if you need 3D positioning.
• Components are created with `CreateDefaultSubobject<T>()` in the actor's constructor, or dynamically with `NewObject<T>() + RegisterComponent()`.
• Component tick is separate from actor tick. Enable with `PrimaryComponentTick.bCanEverTick = true`.
• Calling `DestroyComponent()` marks the component for GC. Detaches it from the owner actor.

Signature

class UActorComponent : public UObject

Example

Creating a custom component C++

UCLASS(ClassGroup=(Custom), meta=(BlueprintSpawnableComponent))
class MYGAME_API UHealthComponent : public UActorComponent
{
    GENERATED_BODY()

public:
    UHealthComponent();

    UPROPERTY(EditAnywhere, BlueprintReadWrite)
    float MaxHealth = 100.f;

protected:
    float CurrentHealth;

    virtual void BeginPlay() override;
};

UHealthComponent::UHealthComponent()
{
    PrimaryComponentTick.bCanEverTick = false;
}

void UHealthComponent::BeginPlay()
{
    Super::BeginPlay();
    CurrentHealth = MaxHealth;
}

Functions (166)

Lifecycle 46 Transform 2 Collision 1 Networking 34 Rendering 24 Navigation 3 Tags 1 Utility 30 Activation 2 Physics 15 Tick 8

Lifecycle

46 ▼

Access	Type	Name	Description
public	function	UActorComponent::Activate	Activates the component if it is not already active (or if bReset is true).
public	function	UActorComponent::BeginPlay	Called when gameplay begins for this component, either when the owning actor begins play or immediately after the component is created if the actor has already begun play.
public	function	UActorComponent::Deactivate	Deactivates the component if it is currently active.
public	function	UActorComponent::EndPlay	Called when gameplay ends for this component.
public	function	UActorComponent::HasBegunPlay	Returns true after BeginPlay has been called on this component and before EndPlay has been called.
public	function	UActorComponent::IsComponentTickEnabled	Returns whether this component's primary tick function is currently enabled.
public	function	UActorComponent::IsRegistered	Returns true if this component is currently registered with the world, meaning it is active, ticking (if enabled), and has its render and physics state initialized.
public	function	UActorComponent::K2_DestroyComponent	Blueprint-callable version of DestroyComponent.
public	function	UActorComponent::ReceiveBeginPlay	Blueprint implementable event fired when the component begins play.
public	function	UActorComponent::ReceiveEndPlay	Blueprint implementable event fired when the component ends play, generally via the actor being destroyed or the level being unloaded.
public	function	UActorComponent::ReceiveTick	Blueprint-implementable event called every frame when ticking is enabled on the component.
public	function	UActorComponent::SetActive	Sets the component's active state in a single call — equivalent to calling Activate() or Deactivate() based on the boolean, but more convenient when toggling from data-driven logic.
public	function	UActorComponent::SetComponentTickEnabled	Enables or disables the primary tick function for this component.
public	function	UActorComponent::TickComponent	Called every frame to update the component.
public	function	UActorComponent::ToggleActive	Flips the component's active state — activates it if currently inactive, deactivates it if currently active.
public	function	UActorComponent::DestroyComponent	Unregisters the component, removes it from its owner Actor's Components array, and marks it for pending kill.
public	function	UActorComponent::HasBeenCreated	Returns true after OnCreatedComponent has been called and before OnDestroyedComponent has been called.
public	function	UActorComponent::HasBeenInitialized	Returns true after InitializeComponent has been called and before UninitializeComponent has been called.
public	function	UActorComponent::InitializeComponent	Called at level startup or actor spawn after registration but before BeginPlay.
public	function	UActorComponent::IsBeingDestroyed	Returns true if the component has begun its destruction sequence but has not yet been fully destroyed.
public	function	UActorComponent::IsReadyForOwnerToAutoDestroy	Returns whether this component will block its owning actor from auto-destroying.
public	function	UActorComponent::OnComponentCreated	Called when a component is created (not loaded from a save).
public	function	UActorComponent::OnComponentDestroyed	Called just before the component is destroyed.
public	function	UActorComponent::RegisterComponent	Registers this component with the world, creating its rendering and physics state.
public	function	UActorComponent::RegisterComponentWithWorld	Registers a component with a world, creating its visual and physical state.
public	function	UActorComponent::ReregisterComponent	Unregisters the component and immediately re-registers it, rebuilding its render and physics state from scratch.
public	function	UActorComponent::SetTickableWhenPaused	Controls whether this component's tick continues to fire while the game is paused.
public	function	UActorComponent::UninitializeComponent	Called from AActor::EndPlay only if InitializeComponent was previously called.
public	function	UActorComponent::UnregisterComponent	Unregisters this component from the world, destroying its rendering and physics state, but does not mark it for garbage collection.
public	function	UActorComponent::AllowReregistration	Returns whether this component class permits automatic reregistration during `ReregisterAllComponents` calls (typically triggered by live editing or component reconstruction).
public	function	UActorComponent::AsyncPhysicsTickComponent	Override to implement custom logic executed every physics sub-step on the physics thread.
public	function	UActorComponent::GetComponentInstanceData	Called before construction scripts are rerun to capture any component state that should survive the component being destroyed and recreated.
public	function	UActorComponent::IsOwnerRunningUserConstructionScript	Returns true while the owning actor is executing its Blueprint User Construction Script (UCS).
public	function	UActorComponent::IsPreRegistered	Returns true when this component has completed its pre-registration pass and is queued for full registration, but has not yet had its rendering and physics state created.
public	function	UActorComponent::IsPreRegistering	Returns true while this component is in the pre-registering phase — after `RegisterComponent` has been called but before the component is fully registered and its physics/render state has been created.
public	function	UActorComponent::IsPreUnregistered	Returns true after the pre-unregistering pass has completed, meaning the component is no longer active but may not yet have been fully removed from the world's component lists.
public	function	UActorComponent::IsPreUnregistering	Returns true while this component is transitioning through the pre-unregistering phase — `UnregisterComponent` has been initiated but render and physics teardown has not yet completed.
public	function	UActorComponent::OnEndOfFrameUpdateDuringTick	Called by the engine when an end-of-frame render update occurs while a tick is still in progress.
public	function	UActorComponent::PostApplyToComponent	Called after ApplyToComponent has run during construction script re-runs.
public	function	UActorComponent::PreRegisterComponentWithWorld	Pre-registers a component with a world as part of incremental level loading.
public	function	UActorComponent::PreUnregisterComponentFromWorld	Pre-unregisters a component from the world when its level is being incrementally removed.
public	function	UActorComponent::ReceiveAsyncPhysicsTick	Blueprint-implementable event called on each async physics sub-step when bAsyncPhysicsTickEnabled is true.
public	function	UActorComponent::RegisterAllComponentTickFunctions	Calls the virtual RegisterComponentTickFunctions chain to register or unregister all tick functions for this component.
public	function	UActorComponent::SetActiveFlag	Directly sets the internal `bIsActive` flag without triggering any virtual overrides or side effects.
public	function	UActorComponent::SetComponentTickEnabledAsync	Spawns a game-thread task that calls SetComponentTickEnabled, allowing tick state changes to be queued from non-game threads without requiring a mutex.
public	function	UActorComponent::SetupActorComponentTickFunction	Configures a tick function with standard component tick rules: tick after the actor, skip static or template actors, and respect the owner's pause-tick setting.

Transform

2 ▼

Access	Type	Name	Description
public	function	UActorComponent::ApplyWorldOffset	Called by the engine when the world origin is rebased or a level is shifted.
public	function	UActorComponent::UpdateComponentToWorld	Recalculates the component-to-world transform matrix.

Collision

1 ▼

Access	Type	Name	Description
public	function	UActorComponent::OnActorEnableCollisionChanged	Called on each component when the owning Actor's bEnableCollision flag changes.

Networking

34 ▼

Access	Type	Name	Description
public	function	UActorComponent::AddReplicatedSubObject	Registers a UObject subobject to be replicated alongside this component using the registered subobject list.
public	function	UActorComponent::CallRemoteFunction	Sends an RPC call for this component to the appropriate remote endpoint via the owning actor's net driver.
public	function	UActorComponent::DestroyReplicatedSubObjectOnRemotePeers	Stops replicating a subobject and signals connected actor channels to delete their replica of it on the next replication update.
public	function	UActorComponent::GetComponentClassCanReplicate	Returns true if this component class is allowed to replicate at all.
public	function	UActorComponent::GetFunctionCallspace	Determines where a UFUNCTION call should execute — locally, on the server, or on clients.
public	function	UActorComponent::GetIsReplicated	Returns true if replication is enabled on this component via SetIsReplicated.
public	function	UActorComponent::GetLifetimeReplicatedProps	Registers which UPROPERTY members should be replicated and under what conditions.
public	function	UActorComponent::GetNetMode	Returns the network mode of the world this component exists in (dedicated server, listen server, client, or standalone).
public	function	UActorComponent::GetOwnerRole	Returns the network role of the actor that owns this component, or ROLE_None if the component has no owner.
public	function	UActorComponent::GetReplicationCondition	Returns the lifetime condition that controls which connections receive this component's replication data.
public	function	UActorComponent::IsNameStableForNetworking	Returns whether this component's name is stable enough to be used for networked object identification.
public	function	UActorComponent::IsNetMode	Returns true if the component's world is currently running in the specified network mode.
public	function	UActorComponent::IsNetSimulating	Returns true when this component is replicating and the local machine does not have authority over it (i.
public	function	UActorComponent::IsNetStartupComponent	Returns true if this component was owned by a net startup actor during level load.
public	function	UActorComponent::IsReadyForReplication	Returns true once ReadyForReplication has been called on the component, indicating it is fully initialised and safe for the replication system to start replicating its properties.
public	function	UActorComponent::IsReplicatedSubObjectRegistered	Returns true if the given subobject is currently registered in this component's replicated subobject list.
public	function	UActorComponent::IsSupportedForNetworking	Returns whether this component supports networking at all.
public	function	UActorComponent::IsUsingRegisteredSubObjectList	Returns true if this component replicates its sub-objects via the registered sub-object list rather than the legacy virtual ReplicateSubObjects method.
public	function	UActorComponent::NeedsLoadForClient	Returns whether this component needs to be loaded on clients.
public	function	UActorComponent::NeedsLoadForServer	Returns whether this component needs to be loaded on dedicated servers.
public	function	UActorComponent::OnCreatedFromReplication	Called when this component is dynamically created on a client as a result of replication from the server.
public	function	UActorComponent::OnDestroyedFromReplication	Called on clients when a replicated component is removed from the network.
public	function	UActorComponent::OnRep_IsActive	RepNotify called on clients when the replicated bIsActive property changes.
public	function	UActorComponent::OnReplicationStartedForIris	Called by the Iris replication system when this component begins replicating.
public	function	UActorComponent::OnStopReplicationForIris	Called by the Iris replication system just before this component stops replicating.
public	function	UActorComponent::PreReplication	Called by the replication system immediately before this component's properties are replicated.
public	function	UActorComponent::ReadyForReplication	Called on replicated components when their owning actor is officially ready for replication.
public	function	UActorComponent::RegisterReplicationFragments	Registers the component's replicated properties as Iris replication fragments.
public	function	UActorComponent::RemoveReplicatedSubObject	Unregisters a subobject so its properties are no longer replicated.
public	function	UActorComponent::ReplicateSubobjects	Legacy virtual called by the networking system to replicate any UObject subobjects owned by this component.
public	function	UActorComponent::SetIsNetStartupComponent	Sets the bIsNetStartupComponent flag.
public	function	UActorComponent::SetIsReplicated	Enables or disables replication for this component.
public	function	UActorComponent::SetNetAddressable	Marks this component as addressable by name over the network, enabling the replication system to identify it without relying on an object index.
public	function	UActorComponent::TearOffReplicatedSubObjectOnRemotePeers	Stops replicating a subobject and releases ownership of its client-side replica, leaving the client copy alive but no longer driven by the server.

Rendering

24 ▼

Access	Type	Name	Description
public	function	UActorComponent::InvalidateLightingCache	Invalidates the component's cached static lighting with default options.
public	function	UActorComponent::IsRenderStateCreated	Returns true if this component currently has a render state (scene proxy) created and registered with the renderer.
public	function	UActorComponent::MarkRenderStateDirty	Marks this component's render state dirty so the scene proxy is fully recreated or updated at the end of the frame.
public	function	UActorComponent::OnActorVisibilityChanged	Called on each component when the owning actor's visibility state changes.
public	function	UActorComponent::ClearNeedEndOfFrameUpdate	Cancels a previously scheduled end-of-frame update or recreate for this component.
public	function	UActorComponent::DoDeferredRenderUpdates_Concurrent	Processes pending render state, dynamic data, and instance data updates for this component by dispatching the appropriate commands to the render thread.
public	function	UActorComponent::GetScene	Returns the rendering scene (FSceneInterface) associated with this component's world.
public	function	UActorComponent::InvalidateLightingCacheDetailed	Override point for subclasses to discard statically cached lighting information when the component has moved or changed.
public	function	UActorComponent::IsHLODRelevant	Override to indicate that this component should be included in HLOD (Hierarchical Level of Detail) proxy generation.
public	function	UActorComponent::IsReadyForEarlyEndOfFrameUpdate	Returns true if this component was marked for end-of-frame update with the bReadyForEarlyUpdate flag, allowing the engine to process it on a worker thread before the strict end-of-frame point.
public	function	UActorComponent::IsRenderInstancesDirty	Returns true if per-instance render data (such as instance transforms or custom data for instanced meshes) is marked dirty and awaiting an update to the renderer.
public	function	UActorComponent::IsRenderStateDirty	Returns true if the full render state for this component is dirty, meaning the scene proxy needs to be fully recreated or updated on the render thread.
public	function	UActorComponent::IsRenderStateRecreating	Returns true while the render state is in the process of being destroyed and recreated due to a MarkRenderStateDirty call.
public	function	UActorComponent::IsRenderStateUpdating	Returns true while DoDeferredRenderUpdates_Concurrent is actively sending this component's render data to the render thread.
public	function	UActorComponent::IsRenderTransformDirty	Returns whether this component's transform has been modified but not yet flushed to the render thread.
public	function	UActorComponent::MarkForNeededEndOfFrameRecreate	Schedules a full render state recreation at end of frame, destroying and rebuilding the scene proxy.
public	function	UActorComponent::MarkForNeededEndOfFrameUpdate	Schedules a deferred SendRenderTransform_Concurrent / SendRenderDynamicData_Concurrent update for end of frame.
public	function	UActorComponent::MarkRenderDynamicDataDirty	Schedules a lightweight dynamic-data update for this component's scene proxy at end of frame.
public	function	UActorComponent::MarkRenderInstancesDirty	Marks per-instance render data (transforms, custom float data) as dirty so it is flushed to the renderer at end of frame.
public	function	UActorComponent::MarkRenderTransformDirty	Marks the component's transform as dirty so it will be sent to the render thread at the end of the current frame.
public	function	UActorComponent::RecreateRenderState_Concurrent	Immediately destroys and recreates the render state (scene proxy) for this component on the render thread.
public	function	UActorComponent::RequiresGameThreadEndOfFrameRecreate	Returns whether end-of-frame scene proxy recreations for this component must happen on the game thread.
public	function	UActorComponent::RequiresGameThreadEndOfFrameUpdates	Returns whether end-of-frame updates for this component must execute on the game thread.
public	function	UActorComponent::RequiresPreEndOfFrameSync	Returns whether this component needs the engine to sync all outstanding async tasks before end-of-frame updates execute.

Navigation

3 ▼

Access	Type	Name	Description
public	function	UActorComponent::CanEverAffectNavigation	Returns whether this component can potentially influence the navigation system.
public	function	UActorComponent::SetCanEverAffectNavigation	Sets the `bCanEverAffectNavigation` flag and updates the navigation octree if needed.
public	function	UActorComponent::IsNavigationRelevant	Override to indicate that this component actively contributes navigation data.

Tags

1 ▼

Access	Type	Name	Description
public	function	UActorComponent::ComponentHasTag	Returns true if the component's ComponentTags array contains the given tag.

Utility

30 ▼

Access	Type	Name	Description
public	function	UActorComponent::GetOwner	Returns the AActor that owns this component by following the Outer chain.
public	function	UActorComponent::GetWorld	Returns the UWorld that this component belongs to, or null if the component has not been registered with a world.
public	function	UActorComponent::AddAssetUserData	Attaches a `UAssetUserData` payload to this component.
public	function	UActorComponent::AdditionalStatObject	Override to return a UObject (typically an asset) whose name will be appended to this component's readable name in stat displays and debug output.
public	function	UActorComponent::ComponentIsInLevel	Returns true if this component's owning actor is contained in the given level.
public	function	UActorComponent::ComponentIsInPersistentLevel	Returns true if this component is in the world's persistent level.
public	function	UActorComponent::GetAssetUserDataArray	Returns a pointer to the internal array of all `UAssetUserData` objects attached to this component.
public	function	UActorComponent::GetAssetUserDataOfClass	Returns the `UAssetUserData` instance of the specified class attached to this component, or null if none exists.
public	function	UActorComponent::GetComponentLevel	Returns the ULevel that this component belongs to, determined by the owning actor's level.
public	function	UActorComponent::GetReadableName	Returns a human-readable display name for this component, including the asset name if AdditionalStatObject() is provided.
public	function	UActorComponent::IsCreatedByConstructionScript	Returns true if this component instance was created by either the user in the Blueprint editor or by the Simple Construction Script (SCS).
public	function	UActorComponent::IsEditableWhenInherited	Returns true if this component can be modified when it was inherited from a parent actor class.
public	function	UActorComponent::RemoveUserDataOfClass	Removes the `UAssetUserData` entry of the specified class from this component.
public	function	UActorComponent::AddReferencedObjects	Static GC hook that registers additional UObject references held by this component with Unreal's garbage collector.
public	function	UActorComponent::ClearUCSModifiedProperties	Clears the entire UCS-modified properties list for this component, resetting all property change tracking from the User Construction Script.
public	function	UActorComponent::DetermineUCSModifiedProperties	Initializes (or refreshes) the internal list of properties that have been modified by the User Construction Script, comparing current values against the class defaults.
public	function	UActorComponent::GetComponentChildElements	Returns the logical child elements of this component for the Typed Elements hierarchy system.
public	function	UActorComponent::GetMarkedForEndOfFrameUpdateState	Returns the internal state flag indicating whether this component has been added to one of the world's end-of-frame render update lists.
public	function	UActorComponent::GetMarkedForPreEndOfFrameSync	Returns the flag indicating whether this component has been queued for the pre-end-of-frame synchronization pass, which flushes certain render updates before the frame completes.
public	function	UActorComponent::GetUCSModifiedProperties	Populates the provided set with pointers to every FProperty that has been modified by the User Construction Script on this component.
public	function	UActorComponent::GetUCSSerializationIndex	Returns the index used to identify this component's position in the User Construction Script serialization stream.
public	function	UActorComponent::IsOwnerSelected	Returns true if this component's owning actor is currently selected in the editor.
public	function	UActorComponent::NeedsLoadForEditorGame	Returns whether this component must be loaded when running the game from the editor (Play-In-Editor).
public	function	UActorComponent::OnPreEndOfFrameSync	Override to perform work — including awaiting async tasks — immediately before the engine sends end-of-frame update data.
public	function	UActorComponent::PostMigrate	Called after this component has been migrated to a new outer or context via the remote object handle system.
public	function	UActorComponent::PostRename	Called immediately after this component has been renamed.
public	function	UActorComponent::RemoveUCSModifiedProperties	Removes specific properties from the component's UCS-modified property list, indicating those properties should no longer be treated as UCS-overridden.
public	function	UActorComponent::Rename	Renames this component and/or moves it to a new outer, updating the owning actor's component lists accordingly.
public	function	UActorComponent::ShouldIncrementalPreRegister	Returns whether PreRegisterComponentWithWorld should be called for this component when its level is being added to the world incrementally.
public	function	UActorComponent::ShouldIncrementalPreUnregister	Returns whether PreUnregisterComponentFromWorld should be called for this component when its level is being removed from the world incrementally.

Activation

2 ▼

Access	Type	Name	Description
public	function	UActorComponent::IsActive	Returns whether the component is currently active.
public	function	UActorComponent::SetAutoActivate	Sets whether the component should automatically activate when it is registered with the world.

Physics

15 ▼

Access	Type	Name	Description
public	function	UActorComponent::IsPhysicsStateCreated	Returns true if the physics state (e.
public	function	UActorComponent::RecreatePhysicsState	Immediately destroys and recreates the physics state for this component.
public	function	UActorComponent::AllowsAsyncPhysicsStateCreation	Override to return true to allow this component's physics state to be created on a background physics thread instead of the game thread.
public	function	UActorComponent::AllowsAsyncPhysicsStateDestruction	Override to return true to allow this component's physics state to be torn down on a background physics thread.
public	function	UActorComponent::CreatePhysicsState	Triggers creation of any physics engine information for this component by calling OnCreatePhysicsState.
public	function	UActorComponent::DestroyPhysicsState	Shuts down any physics engine structures for this component by calling OnDestroyPhysicsState.
public	function	UActorComponent::GetAsyncPhysicsStateObject	Returns the UObject (typically this component itself) that the async physics state job queue uses to identify and schedule work.
public	function	UActorComponent::IsAsyncCreatePhysicsStateRunning	Returns true if the component is currently in the process of asynchronously creating its physics state on a background scene.
public	function	UActorComponent::IsAsyncDestroyPhysicsStateRunning	Returns true if the component is currently in the process of asynchronously destroying its physics state on a background scene.
public	function	UActorComponent::IsAsyncPhysicsStateCreated	Returns true when the async physics state creation job has completed and the physics state is fully live.
public	function	UActorComponent::OnAsyncCreatePhysicsState	Called on a background physics thread to perform the actual async physics state creation work.
public	function	UActorComponent::OnAsyncCreatePhysicsStateEnd_GameThread	Called on the game thread after OnAsyncCreatePhysicsState returns true, signalling that async physics construction is complete.
public	function	UActorComponent::OnAsyncDestroyPhysicsState	Called asynchronously to destroy the physics state for this component.
public	function	UActorComponent::OnAsyncDestroyPhysicsStateBegin_GameThread	Called on the game thread immediately before async physics state destruction begins.
public	function	UActorComponent::OnAsyncDestroyPhysicsStateEnd_GameThread	Called on the game thread after async physics state destruction completes.

Tick

8 ▼

Access	Type	Name	Description
public	function	UActorComponent::AddTickPrerequisiteActor	Adds a dependency so that this component's tick does not run until the specified actor has completed its tick for the frame.
public	function	UActorComponent::AddTickPrerequisiteComponent	Adds a dependency so that this component's tick does not run until the specified component has completed its tick for the frame.
public	function	UActorComponent::GetComponentTickInterval	Returns the tick interval for this component's primary tick function — the frequency in seconds at which it executes.
public	function	UActorComponent::RemoveTickPrerequisiteActor	Removes a previously added tick dependency on the specified actor, allowing this component to tick without waiting for that actor.
public	function	UActorComponent::RemoveTickPrerequisiteComponent	Removes a previously added tick dependency on the specified component, allowing this component to tick without waiting for that component.
public	function	UActorComponent::SetComponentTickInterval	Sets the tick interval for this component's primary tick function.
public	function	UActorComponent::SetComponentTickIntervalAndCooldown	Sets the tick interval for this component's primary tick function with immediate effect, resetting the internal cooldown timer so the next tick fires on the new schedule.
public	function	UActorComponent::SetTickGroup	Changes which tick group this component's primary tick function belongs to, controlling when in the frame it executes relative to physics and other systems.

Properties

Access	Type	Name	Description
public	property	UActorComponent::ComponentTags	An array of FName tags associated with this component.
public	property	UActorComponent::CreationMethod	Describes how this component instance was created: natively in C++ code, via a Blueprint simple construction script, via a user construction script, or as a native child actor.
public	property	UActorComponent::OnComponentActivated	Dynamic multicast delegate fired whenever the component is activated.
public	property	UActorComponent::OnComponentDeactivated	Dynamic multicast delegate fired whenever the component is deactivated.
public	property	UActorComponent::PrimaryComponentTick	The primary tick function for this component.

Version History

Introduced in: 1.0

Version	Status	Notes
5.6	stable	—

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