Interface: implement and call Blueprint interface function

SETUP: Create a Blueprint Interface asset (BPI_Interactable) with a function 'Interact'. IMPLEMENT: In the actor BP, go to Class Settings → Interfaces → Add → BPI_Interactable. Then implement the 'Interact' event that appears in the event graph. CALL: Get actor reference → 'Does Implement Interface(BPI_Interactable)' → Branch → True → 'Interact (Message)' node (the interface call). Key: Interface calls are 'Message' type nodes. Use 'Does Implement Interface' before calling to avoid crashes on actors that don't implement it.

AddForce — apply continuous force to physics body

Continuous force — apply every frame. Use AddImpulse for one-shot.

AddImpulse — apply instant impulse to physics body

One-shot force. bVelChange=true treats Impulse as velocity change.

AddImpulse — apply an instant velocity change to a physics body

bVelChange=true treats Impulse as direct velocity change (ignores mass). bVelChange=false treats it as a force impulse (mass-dependent).

EnhancedInputAction — Enhanced Input system action event

K2Node_EnhancedInputAction. ActionValue type depends on InputAction (Bool, Float, Axis2D, Axis3D). Triggers: Started, Ongoing, Triggered, Completed, Canceled.

Enhanced Input setup: add mapping context and bind actions in UE5

SETUP (once per project): 1. Create Input Mapping Context (IMC_Default) in content browser. 2. Create Input Actions (IA_Move, IA_Jump, IA_Look) — set Value Type. 3. In IMC_Default, map keys to each IA. IN CHARACTER EventBeginPlay: GetController → CastTo<PlayerController> → GetSubsystem(UEnhancedInputLocalPlayerSubsystem) → AddMappingContext(IMC_Default, Priority=0). IN EVENT GRAPH: Right-click → search IA_Move → 'IA_Move (EnhancedInputAction)' node appears with Triggered/Started/Completed exec outputs and 'Action Value' data output. For 2D movement: IA_Move → GetAxis2D(ActionValue) → X to AddMovementInput(GetActorRightVector, ScaleValue=X), Y to AddMovementInput(GetActorForwardVector, ScaleValue=Y).

AddForce — apply a continuous force to a physics body each frame

EnableInput — allow this actor to receive input events

Must call EnableInput(GetPlayerController(0)) before BindAction/BindAxis events fire on the actor.

PlayMontage — play an AnimMontage on a SkeletalMeshComponent

Call on the SkeletalMeshComponent. Get it via GetMesh() on Character. Returns montage length. Exec out is 'then'.

AddMappingContext — add input mapping context to Enhanced Input subsystem

UEnhancedInputLocalPlayerSubsystem::AddMappingContext. Get subsystem via GetEnhancedInputLocalPlayerSubsystem.