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Knowledge base
Knowledge base
Free, anonymous browsing of Unreal Engine Blueprint examples, node references, and best practices. The same content the WoalzCraft plugin uses to generate Blueprints.
34 results for connections
When connecting GetVariable or SetVariable nodes, the pin name must exactly match the variable_name field. E.g. variable 'MyHealth' → pin name 'MyHealth'. SetVariable exec input pin is always 'execute', not 'Execute' or 'in'. GetVariable has no exec pins — it is a pure data node.
Why: You wired a '{pinA}' output to a '{pinB}' input — UE5 doesn't know how to convert between them. The compiler refuses to insert an implicit cast for unsafe conversions. Fix: Right-click between the two nodes and look for a conversion node (e.g. ToString, Truncate, Cast To). If converting between Object types, use Cast To. For numeric conversions, use the dedicated converter nodes. If the conversion truly doesn't make sense, the wiring is logically wrong — re-check the design.
1. DIRECT REFERENCE (tightest coupling): Get reference → CastTo<BP_Other> → call function. Use when: actor A always knows about actor B (e.g. Player → HUD). 2. CAST via GetAllActorsOfClass (loose): find → cast → call. Use when: you need to find actors dynamically. 3. EVENT DISPATCHER (loose): Owner calls dispatcher → listeners receive event. Use when: one actor notifies many others (e.g. death notification). 4. BLUEPRINT INTERFACE (loosest): Call interface message → any implementing actor responds. Use when: multiple different actor types should respond to same action (e.g. 'Interact'). 5. GAME INSTANCE (persistent): Store shared data in GameInstance → GetGameInstance → Cast. Use when: data must survive level loads.
K2_AttachToActor.
Attach Actor To ActorUE 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7updated 2mo agoPattern: Pickup actor with SphereCollision(overlap), StaticMesh visual. OnComponentBeginOverlap → CastTo PlayerCharacter → Success: call AddScore/AddItem interface on player → PlaySoundAtLocation → SpawnEmitterAtLocation → DestroyActor(self). Set collision to OverlapOnlyPawn for performance.
UNiagaraFunctionLibrary::SpawnSystemAtLocation. bAutoDestroy=true for fire-and-forget. Use SpawnSystemAttached to attach to a component.
SpawnSystemAtLocationUE 5.3, 5.4, 5.5, 5.6, 5.7updated 2mo agoK2_AttachToComponent. USceneComponent method.
Attach Component To ComponentUE 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7updated 2mo agoPattern: Actor A declares EventDispatcher OnScoreChanged(int NewScore). Actor B (listener) BeginPlay: GetActorOfClass(A) → BindEvent(OnScoreChanged) → custom event handler. Actor A calls OnScoreChanged.Broadcast(Score) when score changes. Bind in BeginPlay, Unbind in EndPlay to avoid dangling references.
Legacy Cascade system. Prefer Niagara (SpawnSystemAtLocation) for new projects.
SpawnEmitterAtLocationUE 5.3, 5.4, 5.5, 5.6, 5.7updated 2mo agoPattern: 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.