UBlackboardComponent

class AIModule Blueprint Since 4.0

Inherits: UObjectBase › UObjectBaseUtility › UObject › UActorComponent › UBlackboardComponent

#include "BehaviorTree/BlackboardComponent.h"

Description

A component that stores key-value pairs for AI decision-making. Acts as shared memory between the behavior tree, decorators, services, and C++ game code.

Caveats & Gotchas

• Keys must be defined in the UBlackboardData asset in the editor — you cannot add keys at runtime.
• Get the component via AAIController::GetBlackboardComponent(). It is null until UseBlackboard() or RunBehaviorTree() has been called.
• Key names are FName lookups — typos silently fail and return default values. Prefer caching key IDs with GetKeyID() in production code.

Example

Write and read a blackboard value from C++ C++

UBlackboardComponent* BB = AIController->GetBlackboardComponent();
BB->SetValueAsObject(FName("TargetActor"), EnemyActor);

UObject* Target = BB->GetValueAsObject(FName("TargetActor"));

Functions (6)

Blackboard 6

Blackboard

6 ▼

Access	Type	Name	Description
public	function	UBlackboardComponent::GetValueAsFloat	Returns the float value stored under the given blackboard key.
public	function	UBlackboardComponent::GetValueAsObject	Returns the UObject stored under the given blackboard key, or null if the key doesn't exist or holds no value.
public	function	UBlackboardComponent::GetValueAsVector	Returns the FVector stored under the given blackboard key.
public	function	UBlackboardComponent::SetValueAsFloat	Writes a float value to a blackboard key, which can then be read by behavior tree tasks and decorators.
public	function	UBlackboardComponent::SetValueAsObject	Writes a UObject reference to a blackboard key.
public	function	UBlackboardComponent::SetValueAsVector	Writes an FVector to a blackboard key.

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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