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.

ForLoop macro pin reference — FirstIndex LastIndex LoopBody Index Completed

Macro from StandardMacros. LastIndex is inclusive (uses <=).

Macro

An inline-expanded subgraph. Like a function but each use creates a fresh copy at compile time (faster, but more bytecode).

IsValid macro — check validity with exec branch outputs

K2Node_MacroInstance from StandardMacros. Has exec pins unlike the pure IsValid function.

CreateDynamicMaterialInstance — create runtime modifiable material

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

FMod — floating-point modulo (remainder)

string

string

CreateDynamicMaterialInstance — create a runtime-editable material copy

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

Format Text — format text with named arguments

K2Node_FormatText. Use {ArgName} placeholders in format string. Adds input pins per argument automatically.

BooleanAND — logical AND

OR=BooleanOR, NOT=Not_PreBool, XOR=BooleanXOR