Unreal Engine 4 General

Question 1

UCLASS macro

Question 2

USTRUCT macro

Question 3

Why UCLASS and USTRUCT are empty macroses, what are they doing, when to use which?

Question 4

Why does Unreal Engine has it’s own containers?

Question 5

Delegates in Unreal Engine - single, multicast, dynamic, events - what is the difference?

Question 6

UE Interfaces - what is the difference between CPP interfaces?

Question 7

Is there anything special if you call BP Interface in cpp?

Question 8

What is UObject? What abstractions does it represent?

Question 9

What is the difference between UObject and AActor? What is the principal difference?

Question 10

Can UObject do the same functions as AActor?

Question 11

Why AGameState and APlayerState are actors?

Question 12

Why AGameMode and AHUD are actors?

Question 13

Why do we need to use UPROPERTY

Question 14

How to solve cyclical dependencies?

Question 15

When will UObject be destroyed?

Question 16

How to safe object from garbage collector?

Question 17

How actor tick works?

Question 18

What are the main tick groups?

Question 19

AActor lifecycle

Question 20

UActorComponent vs USceneComponent vs UPrimitiveComponent - what is the difference and when to use them?

Question 21

FName vs FString vs FText - what is the difference and when to use them?

Answer 21

FName is hashed and non-case sensitive. Used for IDs, bones, Rownames etc
FString is just string, array of characters + usefull methods for string operations + standard way to interact with other services and APIs. Also used in stringtables as Id
FText used for localization, contains namespace

Question 22

What is CDO

Answer 22

Class Default Object

Question 23

What containers there are in Unreal Engine?

Answer 23

TArray
TSet
TMap

Question 24

What are the fields of usage for different UE containers?

Question 25

What is the difference between Emplace() and Add()

Question 26

Unreal Engine smart pointers - what are the types and how they are working in UE?

Question 27

What creates references between blueprints?

Question 28

UObject* vs TSoftObjectPtr - what is the difference and when to use?

Question 29

TSubclassOf vs TSoftClassPtr - what is the difference and when to use?

Question 30

What are the main threads in UE?

Question 31

Which tasks are working parallel and which are not?

Question 32

How does tick groups work?

Question 33

What actions can be done in their own parallel threads?

Question 34

What actions can’t be completed in parallel threads?

Question 35

How to sync threads with main thread?

Question 36

How to async load resources?

Question 37

What will happen if loadsyncronous called during overall async flow

Answer 37

It will flush the async load, create a stutter