UPrimitiveComponent::OnComponentBeginOverlap

property Engine Blueprint Since unknown

#include "Components/PrimitiveComponent.h"

Access: public Specifiers: UPROPERTYBlueprintAssignable

Description

Delegate fired when another component begins overlapping this component. Requires both components to have overlap responses enabled for the relevant channels.

Signature

FComponentBeginOverlapSignature OnComponentBeginOverlap

Parameters

Name	Type	Description	Default
OverlappedComponent	UPrimitiveComponent*	This component.	—
OtherActor	AActor*	The actor that began overlapping.	—
OtherComp	UPrimitiveComponent*	The specific component on the other actor.	—
OtherBodyIndex	int32	Index of the physics body (relevant for skeletal meshes with multiple bodies).	—
bFromSweep	bool	True if the overlap was detected via a sweep (movement), false if via a proximity check.	—
SweepResult	const FHitResult&	Hit result from the sweep, valid only when bFromSweep is true.	—

Caveats & Gotchas

• Both components must respond to each other's object type with ECR_Overlap (not ECR_Block or ECR_Ignore) for the event to fire.
• Actor-level overlap events (AActor::OnActorBeginOverlap) are fired after the component-level event. Use the component version when you need the specific component reference.
• Dynamically spawned actors may fire OnComponentBeginOverlap during BeginPlay if they spawn inside an existing overlapping volume — handle this case explicitly.

Example

Trigger zone that applies a speed boost C++

void ASpeedZone::BeginPlay()
{
	Super::BeginPlay();
	TriggerVolume->OnComponentBeginOverlap.AddDynamic(this, &ASpeedZone::OnOverlapBegin);
	TriggerVolume->OnComponentEndOverlap.AddDynamic(this, &ASpeedZone::OnOverlapEnd);
}

void ASpeedZone::OnOverlapBegin(UPrimitiveComponent* Comp, AActor* OtherActor,
	UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& Hit)
{
	if (ACharacter* Char = Cast<ACharacter>(OtherActor))
	{
		Char->GetCharacterMovement()->MaxWalkSpeed *= 2.0f;
	}
}

Version History

Introduced in: unknown

Version	Status	Notes
5.6	stable	—

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