Unreal Engine Primer

This article covers the basics of the Unreal Engine interface and also covers core concepts of working with game engines.

You are reading an old article for Unreal Engine 4 - it should still work for Unreal Engine 5 though!

Unreal Engine

Unreal Engine is a game engine, it is a suite of tools to design and build games, experiences, simulations and visualisations. Unreal Engine provides the following functionality that acts as the final pipeline for such projects; rendering engine, lighting, cinematics, sound, special effects, physics/collision engines, interactivity and level scripting. Unreal Engine is used in conjunction with external modelling and animation software that provides the content that will be pieced together and completed with the aforementioned tools.

Unreal Engine uses centimetres.


Editors are the interfaces that allows you to assemble your project. The main editor is the Level Editor which is where all the aspects of the project are put together. Within this you have materials, animation and behaviours, among many other aspects, that have their own dedicated editor. Therefore, this primer will be begin with the Level Editor, other editors will be covered at the same time as their relevant function.

The Level Editor

The level editor is the main way to interface with Unreal Engine.

Unreal Engine uses Centimeters.

This interface can be highly customisable, all articles covering Unreal Engine will be using the default layout.

Content Browser

The content browser is a representation of the layer structure linked to the project, where you can create, import, organise, view and modify content that has been made for the project. This is aided by a variety of functions such as filters and searching.


Editing modes provides access to a variety of environmental assets and generation, such as lighting, effects and terrain.

Tab Bar

Various levels, as well as windows from other projects can be docked here for quick navigation.


The toolbar provides quick access to commonly used tools and operations. For a comprehensive rundown refer to:

The [Build]and [Play] tools are the most relevant and are covered further down this page.


The viewport is where content is put together and should be a familiar concept to 3D-modelling software like Rhino3D.

The default viewport is a single maximised Perspective viewport.

View Options (Left)

This left toolbar persists over each viewport


Tool Name



Viewport Options

Options pertaining to the viewport itself, zoom levels, bookmarked views, FPS counters, convenient camera creation and screenshots can be accessed here.



Options pertaining to what the view is. Viewports can either be perspective or orthographic.


View Mode

Options pertaining to how the view is rendered.



Allows you to show/hide various content.

Transform Options (Right)

This right toolbar is only relevant for the selected viewport


Tool Name



Transform Tools

Translate, Rotate and Scale tools, these manifest as a gizmo at the reference point of the selected object.


Reference System

Toggle between Local or World reference in relation to the transform tools. This affects how the transform tools act, in relation to its own reference (local), or to the level's origin (world).


Snapping Tools

Allows you to turn on and off: -Snapping to surfaces and the snap size

-Rotation snapping and the snap size

-Translation/Scale snapping and the snap size



Speed of the fly-through navigation, covered in Viewport Navigation.

Viewport Control


Tool Name



Maximise/Minimise Viewport

The viewport defaults to a maximised perspective view. Multiple views can be seen at once upon minimising, each with their own

World Outliner

The World Outliner represents the hierarchy of all objects, known as actors, placed inside the level. This works similar to a layer or folder structure. Hierarchy refers to the ability to attach objects to other objects. Actual folders can be created too to manage groups of such Objects

To open the World Outliner [Windows > [World Outliner]





Hide/Show Actor

Hides/Shows the corresponding actor and its effects, but only in the editor preview. Will not stop the object from rendering in-game.



Actors can be attached to other actors by dragging and dropping them to the actor that will constitute the hiearchical layer above it.



Actors can be grouped via [RMB > Move to > Create new Folder]


Contains all the information, utilities and functions specific to the currently selected object.

To open the World Outliner [Windows > [Details]

Viewport Navigation

LMB = Left-Mouse Button

RMB = Right-Mouse Button

The viewport can be navigated in various ways:





Focuses the camera on selected object.

Perspective Camera



LMB + Drag

Moves the camera forward and backward and rotates left and right.

RMB + Drag

Rotates the viewport camera.

LMB + RMB + Drag

Moves up and down.

Orthographic View



LMB + Drag

Creates a marquee selection box.

RMB + Drag

Pans the viewport camera.

LMB + RMB + Drag

Zooms the viewport camera in and out.

Fly Controls

While Holding RMB


W | Numpad8 | Up

Moves the camera forward.

S | Numpad2 | Down

Moves the camera backward.

A | Numpad4 | Left

Moves the camera left.

D | Numpad6| | Right

Moves the camera right.

E | Numpad9 | Page Up

Moves the camera up.

Q | Numpad 7 | Page Dn

Moves the camera down.

Z | Numpad1

Zooms the camera out.

C | Numpad3

Zooms the camera in.

Orbit, Dolly and Track



Alt + LMB + Drag

Tumbles the viewport around a single pivot or point of interest.

Alt + RMB + Drag

Dollies (zooms) the camera toward and away from a single pivot or point of interest.

Alt + MMB + Drag

Tracks the camera left, right, up, and down in the direction of mouse movement.


Your project experience can be thought of as a collection of, or a single level. Levels themselves are collections of geometry, effects, lighting, interactive elements that work together to create the experience.

In Unreal Engine, levels are expressed as objects that are files that can be saved, operated on and opened like any other.

pageProcess: Level Building, Playing & Packaging

Actors & Components

Levels are built from objects known as Actors. Everything in a level is considered an Actor as described in the World Outliner. Actors are composed of groups of Components.


Components are modular pieces consisting of functions that are added to the Actor.


Content is any object that is created externally or internally in Unreal Engine and is referenced by Components.

Local/World Space

Local and World space refers to the reference point in which an Actor is transformed.




For objects in the root, Local space refers to the objects own reference point, and essentially it functions the same as the World reference.

If an object is attached to another, the objects point of reference is the coordinate of that which it is attached to. Origin is the location of the attached object.


A World reference refers to the origin of the current level.

pageActors: Components, Content and Editors

Environment and Effects

Unreal Engine offers tools for the creation of environmental content such as terrain, and tools for rapid distribution of landscape elements. These are accessed through the editing modes and function as sculpting or painting 'brushes.'

Visual and environmental effects are also available, such as particle systems that are used for fire or snow etc., and lighting qualities such as lens flares and volumetric rays. These content are interfaced as you would geometry, some with their own extensive editors too.

pageActors: Components, Content and Editors


Physics and Events

Unreal Engine provides the tools for interacting with the world through the following main systems: physics engines which allows for accurate simulations. Triggers and events allow for the sequencing and control of how Content and the level plays out and unfolds. These systems can only be accessed through the use of Blueprints:


The Blueprint Visual Scripting system is a scripting language based on the concept of using a node-based interface to create gameplay elements, sequencing triggers and events, automated behaviours and interactivity.

Blueprints also refer to a object type that is a package or prefab of components and scripts.

pageInteractivity & Blueprints


Building is the process of Unreal Engine resolving the level so that it can be played, where it compiles any blueprints and code and computes the lighting amongst other background functions. Building is required to ensure your project runs and looks as you intend.

pageProcess: Level Building, Playing & Packaging

Playing: In-editor Testing

Playing is the process of testing the game in editor, allowing you to experience the project as it were the final product but allows you to debug at the same time.

It is good practice to enable the FPS counter from the viewport to quantify the performance of your experience. While the editor itself contributes to some downgrade in performance, this is a good enough indicator of the final result.

pageProcess: Level Building, Playing & Packaging


Packaging is the process of exporting your project so it can be used without the editor as an .exe file.

pageProcess: Level Building, Playing & Packaging

Unreal Engine Marketplace

The marketplace is a source of single models, blueprints/code plugins, materials to complete environments and functioning actors that can be used to help build your experience.

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