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.

LineTraceByChannel — raycast along a line and return first hit

TraceChannel: ETraceTypeQuery::TraceTypeQuery1=Visibility, TraceTypeQuery2=Camera. DrawDebugType: None/ForOneFrame/ForDuration/Persistent.

LineTraceSingle — raycast single hit by channel

UKismetSystemLibrary::LineTraceSingle. WorldContextObject is hidden. End pin is world position, not direction.

Create a Blueprint for a simple FPS weapon that shoots raycasts and deals damage

LineTraceMulti — raycast returning multiple hits

DeprojectScreenToWorld — convert 2D screen position to 3D world ray

Pure node. WorldDirection is the ray direction — multiply by large number and add WorldLocation to get the trace end point for mouse-to-world ray casting.

DeprojectScreenPositionToWorld — convert 2D screen coords to 3D world ray

APlayerController method. WorldDirection is the ray direction for line traces.

Object pooling pattern for frequently spawned actors like projectiles

Pattern: PoolManager with Array<AActor*> AvailablePool. Init: loop SpawnActor N times → SetActorHiddenInGame(true) → SetActorEnableCollision(false) → Array_Add to pool. GetFromPool: Array_Length > 0 → remove last → SetHidden(false) → SetCollision(true) → SetActorLocation → return. ReturnToPool: SetHidden(true) → SetCollision(false) → Array_Add back.

PlayAnimation (widget) — play a Widget Animation

PlaySoundAtLocation — play a 3D positional sound at a world location