Writing Code in Unreal Engine for Unity Developers | Unreal Engine 5.7 Documentation

Setup

C++

To write C++ code in Unreal Engine (UE), download Visual Studio on Windows, or install Xcode on macOS. When you create a new C++ project, UE will automatically create Visual Studio project files for you.

There are two ways to access Visual Studio from your UE project:

In the Content Browser, double-click a C++ class to open it in Visual Studio.
From the main menu, go to Tools > Open Visual Studio. This option only appears if your project contains at least one C++ class.

A critical difference in UE: You will sometimes have to manually refresh your Visual Studio project files (for example, after downloading a new version of UE, or when manually making changes to source file locations on disk.) You can do this in two ways:

From UE's main menu, go to Tools > Refresh Visual Studio Project.
Right-click the .uproject file in your project's directory and select Generate Visual Studio project files.

See Development Setup for more detailed information.

Blueprint

You only need UE to use Blueprint scripting. All the features you need are built into Unreal Editor.

Writing Event Functions

If you previously worked with MonoBehaviors, you are familiar with the Start, Update, and OnDestroy methods. Below is a comparison between a Unity behavior and its equivalent for UE: Actors and Components.

In Unity, you might have a simple component that looks like this:

public class MyComponent : MonoBehaviour
{
	void Start() {}
	void OnDestroy() {}
	void Update() {}
}

public class MyComponent : MonoBehaviour
{
	void Start() {}
	void OnDestroy() {}
	void Update() {}
}

AActor

In UE, you can write code on the Actor itself rather than only coding new component types.

Additionally, Actors have similar methods to Unity's Start, OnDestroy, and Update methods.

C++

UCLASS()
class AMyActor : public AActor
{
	GENERATED_BODY()

	// Called at start of game.
	void BeginPlay();

	// Called when destroyed.
	void EndPlay(const EEndPlayReason::Type EndPlayReason);

Blueprint

UActorComponent

Components in UE are conceptually similar to MonoBehaviors but contain different methods.

C++

UCLASS()
class UMyComponent : public UActorComponent
{
	GENERATED_BODY()

	// Called after the owning Actor was created
	void InitializeComponent();

	// Called when the component or the owning Actor is being destroyed
	void UninitializeComponent();

Blueprint

Additional Notes

In UE, you must explicitly call the parent's method within a child's method. For example, in Unity C# this would be base.Update(), but in UE C++ you will use Super::Tick() for Actors or Super::TickComponent() for Components.
In UE C++, classes use various prefixes, such as U for UObject subclasses and A for Actor subclasses. See Coding Standard for more detailed information.
For gameplay coding examples, see Creating Gameplay in Unreal Engine.