AddToViewport — add widget to the game viewport

UUserWidget::AddToViewport.

Create widget and add to viewport for HUD

Pattern: BeginPlay → CreateWidget(WidgetClass, GetPlayerController(0)) → store as variable → AddToViewport(Widget, ZOrder=0). Remove: RemoveFromParent(Widget). Toggle: SetVisibility(Collapsed/Visible). Create once, toggle visibility — never recreate every frame. For interaction: SetInputModeUIOnly + SetShowMouseCursor.

Create widget, add to viewport, and store reference

Pattern: EventBeginPlay → CreateWidget(OwningPlayer=GetPlayerController, WidgetType=WBP_MyWidget) → SetVariable(HUDWidget=ReturnValue) → CastTo<WBP_MyWidget>(HUDWidget) → Cast Succeeded → AddToViewport(ZOrder=0). Always store widget reference in a variable. CreateWidget inputs: 'OwningPlayer' (PlayerController) and 'WidgetType' (class). Exec in='execute', exec out='then'.

RemoveFromParent — remove widget from viewport

AddToViewport — display a widget on screen

GetPlayerViewPoint — get camera world location and rotation

Outputs are 'Location' and 'Rotation' — NOT ReturnValue. Used for line traces from camera.

Camera

Defines a viewpoint into the world. The active PlayerController's view comes from one camera at a time.

SetVisibility — show or hide a scene component

SetFieldOfView — set camera field of view angle

UCameraComponent method. Default 90.

Line trace raycast for interaction system

Pattern: Input trigger → LineTraceSingle(CameraLocation, CameraLocation + ForwardVector * Distance, Visibility, false, MakeArray(Self), None) → Branch(ReturnValue) → True: BreakHitResult → HitActor → CastTo InteractableInterface → call Interact. End pin is world POSITION not direction. Use DrawDebugType ForOneFrame during dev.