Event Dispatcher: create, bind, and call with custom data

SETUP: In your BP, create an Event Dispatcher (e.g. 'OnPlayerDied') in the My Blueprint panel. BIND (in another BP): Get reference to actor → Bind Event to OnPlayerDied → connect a Custom Event as the target. CALL (in owning BP): Call OnPlayerDied (appears as a pink node) → this broadcasts to all bound listeners. Key: Event Dispatchers are called with 'Call <DispatcherName>' (not 'Broadcast'). Binding is done via 'Bind Event to <DispatcherName>' which has an 'Event' exec-like pin.

Blueprint function vs custom event vs macro: when to use each

BLUEPRINT FUNCTION: - Has its own execution context, can have inputs/outputs/return value. - Cannot have Delay, Timeline, or latent nodes inside. - Best for: pure logic, calculations, data transformation. - Can be overridden in child BPs (if not pure). CUSTOM EVENT: - Lives in event graph, can be called like a function. - CAN have Delay, Timeline, latent nodes. - Can be Replicated (Server/Client/Multicast). - No return value. Best for: triggered behavior, RPC calls. MACRO: - Inlined at call site — like a code template. - CAN have multiple exec inputs AND outputs. - CAN contain latent nodes. - Best for: reusable flow patterns (e.g. 'IsValidAndCast' check-and-cast pattern). PURE FUNCTION: checked 'Pure' — no exec pins, evaluated on demand. Best for getters.

CreateDynamicMaterialInstance — create runtime modifiable material

UPrimitiveComponent method. Store result in variable and reuse. Create once in BeginPlay.

CreateDynamicMaterialInstance — create a runtime-editable material copy

Must call this before SetScalarParameterValue/SetVectorParameterValue. Store the result in a variable for reuse.

Custom Event

A user-defined event you can call from elsewhere in the same graph. Like a function but with an exec output for graphs.

Create dynamic material and animate a parameter at runtime

Pattern: EventBeginPlay → GetMesh → CreateDynamicMaterialInstance(ElementIndex=0) → SetVariable(DynMat=ReturnValue). Then on Tick or timer: SetScalarParameterValue(ParameterName='Opacity', Value=SinWave). Or for color: SetVectorParameterValue(ParameterName='Color', Value=MakeLinearColor). Key: CreateDynamicMaterialInstance is called on the COMPONENT (GetMesh), not the actor. Must store the result before using Set*ParameterValue. ParameterName MUST match the name in the Material asset exactly.

Cast to player character subclass and access custom variables

Pattern: GetPlayerCharacter(PlayerIndex=0) → CastTo<BP_MyCharacter>(Object=ReturnValue) → Cast Succeeded → Get/Set variables on 'As BP_MyCharacter' output pin. Key: CastTo exec input='execute', exec output='Cast Succeeded'/'Cast Failed'. The cast output pin is named 'As BP_MyCharacter' (or whatever your class is). Connect this output to any node that needs the typed reference.

UserWidget

Parent class for Widget Blueprints. Override Construct, Tick, OnPaint, etc.

BuildString — build formatted string with prefix, suffix, and value

Also: BuildString_Int, BuildString_Name, BuildString_Vector, etc.

MakeColor — construct FLinearColor from R G B A