Unreal Engine Blueprints Functions, Events, and Macros 2 — Questions and Answers
Question 1: What happens when you call a Function node that has no Return Node in Blueprints?
- The function returns a default value for each output pin type (Correct answer)
- The compiler throws a fatal error and the Blueprint cannot be compiled
- The function executes but skips any code after the call site
- Unreal Engine automatically inserts a Return Node at compile time
Correct answer: The function returns a default value for each output pin type
If a Blueprint function has output pins but no Return Node, those outputs return default values (0, false, empty string, etc.).
Question 2: Which keyword correctly describes a Blueprint Macro's execution pins compared to a Function's execution pins?
- Macros can have multiple input and output execution pins; Functions have exactly one of each (Correct answer)
- Functions can have multiple input execution pins; Macros have exactly one
- Both Macros and Functions are limited to one input and one output execution pin
- Macros have no execution pins; only data pins are allowed
Correct answer: Macros can have multiple input and output execution pins; Functions have exactly one of each
Blueprint Macros support multiple input and output execution pins, making them suitable for branching logic, unlike functions which have a single entry and exit.
Question 3: In Blueprints, what is the primary reason Custom Events can be called from other Blueprints while standard graph events (like BeginPlay) cannot be triggered externally?
- Custom Events appear as callable nodes when you reference another Blueprint's object (Correct answer)
- Standard events are marked private by default and cannot be exposed
- Custom Events compile to public functions in the underlying C++ class
- Standard events require a delegate binding before they can be called externally
Correct answer: Custom Events appear as callable nodes when you reference another Blueprint's object
Custom Events generate a callable node that appears in other Blueprints when you have a reference to the owning actor, making cross-Blueprint calls straightforward.
Question 4: What does checking 'Pure' on a Blueprint Function do?
- Removes execution pins so the function can be used inline like a getter (Correct answer)
- Prevents the function from modifying any variables in the Blueprint
- Marks the function as thread-safe for multithreaded execution
- Forces the function to be inlined at every call site by the compiler
Correct answer: Removes execution pins so the function can be used inline like a getter
Marking a function Pure removes its execution pins, allowing it to be wired directly into data inputs without needing an execution wire.
Question 5: A Blueprint Macro is placed in a MacroLibrary asset. Which statement about this macro is TRUE?
- It can be used by any Blueprint that includes the MacroLibrary without needing an object reference (Correct answer)
- It requires an instance of the MacroLibrary to be spawned in the level
- It can only be used by Blueprints that inherit from the same parent class
- It must be re-compiled each time the Blueprint using it is opened
Correct answer: It can be used by any Blueprint that includes the MacroLibrary without needing an object reference
Macros in a Blueprint MacroLibrary are accessible globally to any Blueprint that has the library referenced, with no object instance required.
Question 6: Which of the following CANNOT be done inside a Blueprint Function that is marked as 'Const'?
- Setting a variable that belongs to the owning Blueprint (Correct answer)
- Reading a variable that belongs to the owning Blueprint
- Calling another Const function on the same Blueprint
- Returning a computed value based on input parameters
Correct answer: Setting a variable that belongs to the owning Blueprint
A Const function guarantees it will not modify the object's state, so setting any member variable is disallowed inside it.
Question 7: When using the 'Delay' node inside a Blueprint, where must it be placed and why?
- Inside a Custom Event or standard event graph, because Delay uses latent actions which require an event context (Correct answer)
- Inside a Function, because Functions run on a separate thread that can be paused
- Inside a Macro, because Macros support asynchronous execution natively
- Anywhere in the graph; Delay works identically in Functions, Macros, and Events
Correct answer: Inside a Custom Event or standard event graph, because Delay uses latent actions which require an event context
Delay is a latent node that relies on the game's tick system and can only be used in event graphs or Custom Events, not inside Blueprint Functions.
Unreal Engine Blueprints Functions, Events, and Macros 2
What happens when you call a Function node that has no Return Node in Blueprints?