Components

An Actor by itself is an empty shell — it exists in the world but doesn't do anything. Components are the LEGO pieces you snap onto an Actor to give it shape, behavior, and personality.

Want your Actor to have a 3D model? Attach a StaticMeshComponent. Need it to play sounds? Add an AudioComponent. Want it to collide with things? Slap on a CollisionComponent.

Common Component Types

Component	What it does
StaticMeshComponent	Gives the Actor a visible 3D model
SkeletalMeshComponent	A 3D model with a skeleton for animation
BoxCollisionComponent	Simple box-shaped collision detection
SphereCollisionComponent	Spherical collision detection
AudioComponent	Plays sounds in 3D space
PointLightComponent	Emits light from a single point
CameraComponent	Adds a camera viewpoint
CharacterMovementComponent	Handles walking, jumping, falling, swimming

Adding Components

In HELIX Studio, you can add components visually in the Blueprint editor's Components panel — hit Add and pick what you need. You can also add them at runtime through code:

Blueprint

// In Blueprints, use "Add Component" nodes
// Or in the Components panel of the Blueprint editor, click "+ Add"

// C++ equivalent:
UStaticMeshComponent* MeshComp = CreateDefaultSubobject<UStaticMeshComponent>(
    TEXT("MyMesh")
);
MeshComp->SetupAttachment(RootComponent);

Lua

-- Add a static mesh component to an actor
function MyActor:Initialize(Initializer)
    local mesh_comp = Initializer:CreateDefaultSubobject(
        "MyMesh", UE.UStaticMeshComponent
    )
    self.RootComponent = mesh_comp
end

JavaScript

// Add a static mesh component to an actor
class MyActor extends ue.Actor {
    Constructor() {
        let meshComp = this.CreateDefaultSubobject(
            "MyMesh", ue.StaticMeshComponent
        );
        this.RootComponent = meshComp;
    }
}

The Component Hierarchy

Components form a tree. Every Actor has a Root Component at the top, and other components attach underneath it. When the root moves, everything attached moves with it — like a puppet on strings.

MyCharacter (Actor)
├── CapsuleComponent (Root)
│   ├── SkeletalMeshComponent
│   │   └── AudioComponent
│   └── CameraComponent
└── CharacterMovementComponent

Building Blocks, Not Monoliths

The beauty of components is reusability. Instead of creating a totally new Actor class for every object, you mix and match components. A treasure chest and a mailbox might share the same InteractableComponent — different look, same open/close behavior. Build small, compose big.

tip

If you find yourself copying logic between Actor classes, that logic probably belongs in a shared component instead.