Damage number popup floating text in world space

Pattern: WBP_DamageNumber widget with TextBlock. On damage dealt: CreateWidget(WBP_DamageNumber) → SetText(Damage amount) → AddToViewport. Tick: ProjectWorldLocationToScreen(DamageLocation + UpOffset) → SetPositionInViewport. Timeline Alpha 0→1 over 1s: SetColorAndOpacity(FadeOut) + move up. OnFinished: RemoveFromParent. Alternative: use WidgetComponent in world space.

Button

A clickable UMG widget. Hook OnClicked in the Graph to handle the press.

EnhancedInputAction — Enhanced Input system action event

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

AddToViewport — display a widget on screen

string

string

Create a Blueprint for a door that opens when the player overlaps a trigger and closes when they leave

Mouse click to world: detect clicked actor or ground position

On Left Mouse Button pressed → GetHitResultUnderCursorByChannel(TraceChannel=Visibility) → Branch(ReturnValue=true) → BreakHitResult → Check HitActor: IsValid(HitActor) → Branch → True: interact with HitActor. Check ground: use ImpactPoint as the world position clicked. GetHitResultUnderCursorByChannel is on PlayerController. Inputs: 'TraceChannel' (ETraceTypeQuery) and 'bTraceComplex' (bool). Output: 'HitResult' (struct) and 'ReturnValue' (bool). Use BreakHitResult to get ImpactPoint, HitActor, etc.

Level transition with loading screen

Pattern: CreateWidget(WBP_LoadingScreen) → AddToViewport(ZOrder=100) → LoadStreamLevel or OpenLevel(NewMapName). For async: AsyncLoadLevel → OnCompleted → RemoveFromParent(LoadingWidget). Store persistent data in GameInstance before transition. Use Seamless Travel for multiplayer.

OnComponentBeginOverlap — overlap event on specific component

Bind to specific UPrimitiveComponent. More precise than actor overlap.

Gate — open/close/toggle flow gate

Macro. Enter only passes through when gate is open.