AActor::AddComponentByClass

function Engine Blueprint Since 4.26

#include "GameFramework/Actor.h"

Access: public Specifiers: UFUNCTIONBlueprintCallable

Description

Blueprint-internal function that creates a component from a class reference rather than a named template, powering the 'Add Component by Class' Blueprint node. Like AddComponent, this should not be called from C++ game code.

Caveats & Gotchas

• The AllowAbstract=false meta restriction is enforced in Blueprint only — abstract classes can still be passed in C++, which will result in a failed NewObject call and a nullptr return.
• This is a Blueprint-internal function (marked 'DO NOT CALL MANUALLY'). In C++ use NewObject<T>() + RegisterComponent() for runtime component addition.
• Unlike AddComponent, there is no template lookup — it instantiates the class directly. Expose-on-spawn properties are not supported through this path unless you use bDeferredFinish=true and set them before calling FinishAddComponent.

Signature

ENGINE_API UActorComponent* AddComponentByClass(UPARAM(meta = (AllowAbstract = "false")) TSubclassOf<UActorComponent> Class, bool bManualAttachment, const FTransform& RelativeTransform, bool bDeferredFinish)

Parameters

Name	Type	Description	Default
Class	TSubclassOf<UActorComponent>	The concrete component class to instantiate.	—
bManualAttachment	bool	If false, auto-attaches to root. If true, caller handles attachment.	—
RelativeTransform	const FTransform&	Relative transform to apply when auto-attaching.	—
bDeferredFinish	bool	If true, delays final registration until FinishAddComponent() is called.	—

Return Type

UActorComponent*

Example

C++ equivalent pattern (preferred over AddComponentByClass) C++

// AddComponentByClass() is for Blueprint nodes. In C++:
UPointLightComponent* Light = NewObject<UPointLightComponent>(this);
Light->SetupAttachment(GetRootComponent());
Light->SetRelativeTransform(RelativeTransform);
Light->RegisterComponent();

Version History

Introduced in: 4.26

Version	Status	Notes
5.6	stable	—

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