Choosing a C++/BP Parent Class in Unreal Engine

Most used classes

None

• Default constructor and destructor, nothing more

The list below is based on the Inheritance Hierarchy, which basically means that each inherited class just extends a functionality of its parent class for own extra features, see the list below.

• UObject
  • UWorld

    UWorld is a base class representing a game world in Unreal Engine. Each project usually has one main instance of UWorld, in which all levels (ULevelStreaming) and activities of the game are located. UWorld contains information about the game environment, such as current players, current cameras, characters and objects in the game world.

  • AActor

    • Can be placed in the world
    • Can have a visual representation (Mesh, ...)
    • Has function for spawning to the world
    • Has functions for processing movement

    A at the start of class names below refers to the information that the classes are inherited from the Actor class.

    • APawn

      • Anything that can be possessed as a player, by a Controller
      • Handles movement input

      • ACharacter

        • It has Character movement component with a bunch of predefined movement modes (flying, swimming, crouching...) for bipedal characters. It offers also usefult functions such as e.g. IsFalling() for setting e.g. an custom airborne variable that is used for switching between State Machine animations.
        • As mentioned, ACharacter is usable especially for bipedal characters. In a case of other characters, it is usually better to inherit from APawn and define the movement logic on your own.

    • AInfo

      • AGameModeBase

        • Ideal for keeping rules, such as win condition
        • Sets default Pawn class
        • Starting / ending the application
        • Can be set as defualt GameMode at Project Settings → Maps & Modes → Default GameMode

        • AGameMode

          • Match state concept for Multiplayer Matches

    • AController

      • APlayerController

        Class for controlling the pawn properties, such as mouse pointer visual, camera shakes and so on. It's attached to AGameModeBase.

        It also manages player's View Point. View Point is handy when we there is need to reflect the property that the camera and e.g. a gun to aim to a different point. View point of the camera can be got from any actor (such as a gun) as follow OwnerController->GetPlayerViewPoint(VarToSaveLocation, VarToSaveRoration);

        Access GameMode functions from any class

        #include ExapleProjectGameModeBase.h
                AExampleProjectGameModeBase* GameMode = GetWorld()->GetAuthGamemode<AExampleProjectGameModeBase>();
                if(GameMode != nullptr){
                    GameMode->PawnKilledCustomFunction(this);
                }

      • AAIController

        While the APlayerController relies on the human player to make decisions on what to do, the AIController is more focused on responding to input from the environment and game world. The job of the AIController is to observe the world around it and make decisions and react accordingly without explicit input from a human player.

  • UVisual
    • UWidget

      • UUserWidget

        A class responsible for Blueprint UI widget accessible through User Interface → Widget Blueprint.

  • UDataTable

• UBlueprintFunctionLibrary

  Base class for any function libraries exposed to blueprints. Methods in subclasses are expected to be static, and no methods should be added to this base class. It's also very handy for editor-based stuff and tools (works with files and so on).

  • UGameplayStatics

    A static class through which may be accessed any gameplay statics from any class.

ActorComponent

Creates an UActor derived component that can be placed as a component through Blueprint into any Blueprint Actor. It may keep variables and functionality for certain area, e.g. for the health in a case of custom Health component. The main benefir is that it can by reused with any classes.

Also, it can be binded (e.g. GetOwner()->OnTakeAnyDamage.AddDynamic(this, &UHealthComponent::DamageTaken)) to any Actor-inherited component in C++ for event handling.

Other interesting classes

FTimerManager

Class to globally manage timers - use it anytime there's a need to work with a time.

Animation Blueprints

Allows to set a logic for animations to combine and display animations from a list based on the input value.