Unreal Engine (UE) is a 3D computer graphics

game engine A game engine is a software framework primarily designed for the development of video games which generally includes relevant libraries and support programs such as a level editor. The "engine" terminology is akin to the term " software engine" u ...

developed by

Epic Games Epic Games, Inc. is an American Video game developer, video game and software development, software developer and video game publisher, publisher based in Cary, North Carolina. The company was founded by Tim Sweeney (game developer), Tim Sween ...

, first showcased in the 1998

first-person shooter A first-person shooter (FPS) is a video game genre, video game centered on gun fighting and other weapon-based combat seen from a First person (video games), first-person perspective, with the player experiencing the action directly through t ...

video game '' Unreal''. Initially developed for PC first-person shooters, it has since been used in a variety of genres of games and has been adopted by other industries, most notably the film and television industry. Unreal Engine is written in C++ and features a high degree of portability, supporting a wide range of

desktop A desktop traditionally refers to: * The surface of a desk (often to distinguish office appliances that fit on a desk, such as photocopiers and printers, from larger equipment covering its own area on the floor) Desktop may refer to various compu ...

, mobiles,

console Console may refer to: Computing and video games * System console, a physical device to operate a computer ** Virtual console, a user interface for multiple computer consoles on one device ** Command-line interface, a method of interacting with ...

, and

virtual reality Virtual reality (VR) is a Simulation, simulated experience that employs 3D near-eye displays and pose tracking to give the user an immersive feel of a virtual world. Applications of virtual reality include entertainment (particularly video gam ...

platforms. The latest generation,

Unreal Engine 5 Unreal Engine 5 (UE5) is the latest version of Unreal Engine developed by Epic Games. It was revealed in May 2020 and officially released in April 2022. Unreal Engine 5 includes multiple upgrades and new features, including Nanite, a system that ...

, was launched in April 2023. Its source code is available on

GitHub GitHub () is a Proprietary software, proprietary developer platform that allows developers to create, store, manage, and share their code. It uses Git to provide distributed version control and GitHub itself provides access control, bug trackin ...

, and commercial use is granted based on a royalty model, with Epic charging 5% of revenues over US $1 million, which is waived for games published exclusively on the Epic Games Store. Epic has incorporated features in the engine from acquired companies such as Quixel, which is seen as benefiting from ''

Fortnite ''Fortnite'' is an online video game and game platform developed by Epic Games and released in 2017. It is available in seven distinct game mode versions that otherwise share the same general gameplay and game engine: '' Fortnite Battle Roy ...

'''s revenue.

History

First generation

Unreal Engine 1 was initially developed in 1995 by Epic Games founder Tim Sweeney for ''Unreal'' and used

software rendering Software consists of computer programs that instruct the execution of a computer. Software also includes design documents and specifications. The history of software is closely tied to the development of digital computers in the mid-20th cen ...

. It supported

Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

Mac Mac or MAC may refer to: Common meanings * Mac (computer), a line of personal computers made by Apple Inc. * Mackintosh, a raincoat made of rubberized cloth * Mac, a prefix to surnames derived from Gaelic languages * McIntosh (apple), a Canadi ...

and

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

. Epic later began to license the Engine to other game studios.

Unreal Engine 2

Unreal Engine 2 transitioned the engine from software rendering to hardware rendering and brought support for the

PlayStation 2 The PlayStation 2 (PS2) is a home video game console developed and marketed by Sony Interactive Entertainment, Sony Computer Entertainment. It was first released in Japan on 4 March 2000, in North America on 26 October, in Europe on 24 Novembe ...

Xbox Xbox is a video gaming brand that consists of four main home video game console lines, as well as application software, applications (games), the streaming media, streaming service Xbox Cloud Gaming, and online services such as the Xbox networ ...

, and

GameCube The is a PowerPC-based home video game console developed and marketed by Nintendo. It was released in Japan on September 14, 2001, in North America on November 18, 2001, in Europe on May 3, 2002, and in Australia on May 17, 2002. It is the suc ...

consoles. The first game using UE2 was released in 2002 and its last update was shipped in 2005.

Unreal Engine 3

Unreal Engine 3 was one of the first game engines to support multithreading. It used DirectX 9 as its baseline graphics API, simplifying its rendering code. The first games using UE3 were released at the end of 2006.

Unreal Engine 4

Unreal Engine 4 brought support for physically based materials and the "Blueprints" visual scripting system. The first game using UE4 was released in April 2014. It was the first version of Unreal to be free to download with royalty payments on game revenue.

Unreal Engine 5

Unreal Engine 5 features Nanite, a virtualized geometry system that allows game developers to use arbitrarily high quality meshes with automatically generated Level of Detail, and Lumen, a dynamic global illumination and reflections system that uses software and hardware ray tracing. It was revealed in May 2020 and officially released in April 2022.

Unreal Engine 6

Sweeney discussed Unreal Engine 6 on the

Lex Fridman Alexei "Lex" Fridman (; born 15 August 1983) is an American computer scientist and podcaster. Since 2018, he has hosted the ''Lex Fridman Podcast'', where he interviews notable figures from various fields such as science, technology, sports, and ...

podcast in 2025, and indicated that the first preview builds would be available in two to three years. The next version will aim to unify the currently separate development streams used for ''Fortnite'' and the broader engine.

Scripting

UnrealScript

UnrealScript (often abbreviated to UScript) was Unreal Engine's native

scripting language In computing, a script is a relatively short and simple set of instructions that typically automation, automate an otherwise manual process. The act of writing a script is called scripting. A scripting language or script language is a programming ...

used for authoring game code and

gameplay Gameplay is the specific way in which players interact with a game. The term applies to both video games and Tabletop game, tabletop games. Gameplay is the connection between the player and the game, the player's overcoming of challenges, and t ...

events before the release of Unreal Engine 4. The language was designed for simple, high-level

game programming Game programming, a subset of game development, is the software development of video games. Game programming requires substantial skill in software engineering and computer programming in a given language, as well as specialization in one or ...

. UnrealScript was programmed by Tim Sweeney, who also created an earlier game scripting language,

ZZT-OOP ''ZZT'' is a 1991 action-adventure puzzle video game and game creation system developed and published by Potomac Computer Systems for MS-DOS. It was later released as freeware in 1997. It is an early game allowing user-generated content using ...

. ''

Deus Ex ''Deus Ex'' is a series of cyberpunk role-playing video games, set during the mid 21st century. Focusing on the conflict between secretive factions who wish to control the world by proxy, and the effects of transhumanistic attitudes and technol ...

'' lead programmer Chris Norden described it as "super flexible" but noted its low execution speed. Similar to

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

, UnrealScript was

object-oriented Object-oriented programming (OOP) is a programming paradigm based on the concept of '' objects''. Objects can contain data (called fields, attributes or properties) and have actions they can perform (called procedures or methods and impleme ...

without

multiple inheritance Multiple inheritance is a feature of some object-oriented computer programming languages in which an object or class can inherit features from more than one parent object or parent class. It is distinct from single inheritance, where an object ...

(classes all inherit from a common Object class), and classes were defined in individual files named for the class they define. Unlike Java, UnrealScript did not have object wrappers for primitive types. Interfaces were only supported in Unreal Engine generation 3 and a few Unreal Engine 2 games. UnrealScript supported

operator overloading In computer programming, operator overloading, sometimes termed ''operator ad hoc polymorphism'', is a specific case of polymorphism, where different operators have different implementations depending on their arguments. Operator overloading ...

, but not

method overloading In some programming languages, function overloading or method overloading is the ability to create multiple functions of the same name with different implementations. Calls to an overloaded function will run a specific implementation of that f ...

, except for optional parameters. At the 2012 Game Developers Conference, Epic announced that UnrealScript was being removed from Unreal Engine 4 in favor of C++. Visual scripting would be supported by the Blueprints Visual Scripting system, a replacement for the earlier Kismet visual scripting system.

Verse

Verse is the new scripting language for Unreal Engine, first implemented in ''

''.

Simon Peyton Jones Simon Peyton Jones (born 18 January 1958) is a British computer scientist who researches the implementation and applications of functional programming languages, particularly lazy functional programming. Education Peyton Jones graduated fro ...

, known for his contributions to the

Haskell Haskell () is a general-purpose, statically typed, purely functional programming language with type inference and lazy evaluation. Designed for teaching, research, and industrial applications, Haskell pioneered several programming language ...

programming language, joined Epic Games in December 2021 as Engineering Fellow to work on Verse with his long-time colleague Lennart Augustsson and others. Conceived by Sweeney, it was officially presented at Haskell eXchange in December 2022 as an open source functional-logic language for the

metaverse The metaverse is a loosely defined term referring to virtual worlds in which users represented by avatars interact, usually in 3D and focused on social and economic connection. The term ''metaverse'' originated in the 1992 science fiction ...

. A research paper, titled ''The Verse Calculus: a Core Calculus for Functional Logic Programming'', was also published. The language was eventually launched in March 2023 as part of the release of the Unreal Editor for ''Fortnite'' ( UEFN) at the Game Developers Conference, with plans to be available to all Unreal Engine users by 2025.

Marketplace

With Unreal Engine 4, Epic opened the Unreal Engine Marketplace in September 2014. The Marketplace is a digital storefront that allows content creators and developers to provide art assets, models, sounds, environments, code snippets, and other features that others could purchase, along with tutorials and other guides. Some content is provided for free by Epic, including previously offered Unreal assets and tutorials. Prior to July 2018, Epic took a 30% share of the sales but due to the success of Unreal and ''

Fortnite Battle Royale ''Fortnite Battle Royale'' is a 2017 Battle royale game, battle royale video game produced by Epic Games. It was originally developed as a companion game part of the early access version of ''Fortnite: Save the World'', a cooperative survival ...

'', Epic retroactively reduced its take to 12%.

Usage

Video games

Unreal Engine was originally designed to be used as the underlying technology for video games. The engine is used in a number of high-profile game titles with high graphics capabilities, including ''

Hogwarts Legacy ''Hogwarts Legacy'' is a 2023 action role-playing game developed by Avalanche Software and published by Warner Bros. Games under its Portkey Games label. It is part of the Wizarding World franchise, taking place a century prior to the ''Harry ...

'', '' PUBG: Battlegrounds'', ''

Final Fantasy VII Remake is a 2020 action role-playing game developed and published by Square Enix for the PlayStation 4. It is the first in a planned trilogy of games remaking Square's '' Final Fantasy VII'' (1997), originally released for the PlayStation. An enhan ...

'', ''

Valorant ''Valorant'' is a 2020 First-person shooter, first-person tactical shooter, tactical hero shooter video game developed and published by Riot Games. A free-to-play game, ''Valorant'' takes inspiration from the ''Counter-Strike'' series, borrow ...

'' and '' Yoshi's Crafted World,'' in addition to games developed by Epic, including ''Gears of War'' and ''Fortnite''. Polish game developer

CD Projekt CD Projekt S.A. () is a Polish video game company based in Warsaw, founded in May 1994 by Marcin Iwiński and Michał Kiciński. Iwiński and Kiciński were video game retailers before they founded the company, which initially acted as ...

is also planning to use the engine after retiring their in-house REDengine; their first game to use Unreal will be a remake of '' The Witcher''. Usage of Unreal Engine has been steadily increasing since 2012, from an estimated 17% market share to 28% in 2024, compared to Unity's 50%. By sales, Unreal accounts for 31% compared to Unity's 26%, with proprietary engines accounting for a combined 42%, making Unreal the largest engine by units sold.

Film and television

Unreal Engine has found use in filmmaking to create virtual sets that can track with a camera's motion around actors and objects and be rendered in real time to large

LED A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresp ...

screens and atmospheric lighting systems. This allows for real-time composition of shots, immediate editing of the virtual sets as needed, and the ability to shoot multiple scenes within a short period by just changing the virtual world behind the actors. The overall appearance was recognized to appear more natural than typical chromakey effects. Among the productions to use these technologies were the live action television series ''

The Mandalorian ''The Mandalorian'' is an American space Western television series created by Jon Favreau for the streaming service Disney+. It is the first live-action series in the ''Star Wars'' franchise and begins five years after the events of the fil ...

'', ''

Westworld ''Westworld'' is an American science fiction dystopia media franchise that began with the Westworld (film), 1973 film ''Westworld'', written and directed by Michael Crichton. The film depicts a technologically advanced Wild West, Wild-West-th ...

'' and ''

Fallout Nuclear fallout is residual radioactive material that is created by the reactions producing a nuclear explosion. It is initially present in the radioactive cloud created by the explosion, and "falls out" of the cloud as it is moved by the ...

'', and the animated series '' Zafari'' and '' Super Giant Robot Brothers''.

Jon Favreau Jonathan Kolia Favreau ( ; born October 19, 1966) is an American actor and filmmaker. As an actor, Favreau has appeared in films such as ''Rudy (film), Rudy'' (1993), ''PCU (film), PCU'' (1994), ''Swingers (1996 film), Swingers'' (1996), ''Very ...

and

Lucasfilm Lucasfilm Ltd. LLC is an American film and television production company founded by filmmaker George Lucas in December 10, 1971 in San Rafael, California, and later moved to San Francisco in 2005. It is best known for creating and producing th ...

Industrial Light & Magic Industrial Light & Magic (ILM) is an American Film, motion picture visual effects, computer animation and stereo conversion digital studio founded by George Lucas on May 26, 1975. It is a division of the film production company Lucasfilm, which Lu ...

division worked with Epic in developing their

StageCraft Stagecraft is a technical aspect of theatrical, film, and video production. It includes constructing and rigging scenery; hanging and focusing of lighting; design and procurement of costumes; make-up; stage management; audio engineering; ...

technology for ''The Mandalorian'', based on a similar approach Favreau had used in ''

The Lion King ''The Lion King'' is a 1994 American animated musical coming-of-age drama film directed by Roger Allers and Rob Minkoff, produced by Don Hahn, and written by Irene Mecchi, Jonathan Roberts, and Linda Woolverton. Produced by Walt Disney ...

''. Favreau then shared this technology approach with ''Westworld'' producers

Jonathan Nolan Jonathan Jensen Nolan (born 6 June 1976) is a British and American screenwriter and producer. He is the creator of the CBS science fiction series '' Person of Interest'' (2011–2016) and of the HBO science fiction/Western series ''Westworld'' ...

and

Lisa Joy Lisa Joy (born May 23, 1977) is an American screenwriter, director, producer, and lawyer. She is best known as the co-creator, writer, director, and executive producer of the HBO science-fiction drama series ''Westworld'' (2016–2022). For her ...

. The show had already looked at the use of virtual sets before and had some technology established, but integrated the use of Unreal Engine as with StageCraft for its third season. Orca Studios, a Spanish-based company, has been working with Epic to establish multiple studios for virtual filming similar to the StageCraft approach with Unreal Engine providing the virtual sets, particularly during the

COVID-19 pandemic The COVID-19 pandemic (also known as the coronavirus pandemic and COVID pandemic), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), began with an disease outbreak, outbreak of COVID-19 in Wuhan, China, in December ...

, which restricted travel. In January 2021, ''

Deadline Hollywood ''Deadline Hollywood'', commonly known as ''Deadline'' and also referred to as ''Deadline.com'', is an online news site founded as the news blog ''Deadline Hollywood Daily'' by Nikki Finke in 2006. It is updated several times a day, with en ...

'' announced that Epic was using part of its Epic MegaGrants to back for the first time an animated feature film, ''Gilgamesh'', to be produced fully in Unreal Engine by animation studios Hook Up, DuermeVela and FilmSharks. As part of an extension of its MegaGrants, Epic also funded 45 additional projects since around 2020 for producing feature-length and short films in the Unreal Engine. By October 2022, Epic was working with several different groups at over 300 virtual sets across the world. Unreal Engine was used for

motion capture Motion capture (sometimes referred as mocap or mo-cap, for short) is the process of recording high-resolution motion (physics), movement of objects or people into a computer system. It is used in Military science, military, entertainment, sports ...

in ''

Lyle, Lyle, Crocodile ''Lyle, Lyle, Crocodile'' is a children's book written by Bernard Waber first published in 1965. It is the sequel to '' The House on East 88th Street'', published in 1962. The book is the second in the ''Lyle the Crocodile'' series, which fo ...

''.

Other uses

Unreal Engine has also been used by non-creative fields due to its availability and feature sets. It has been used as a basis for a virtual reality tool to explore pharmaceutical drug molecules in collaboration with other researchers, as a virtual environment to explore and design new buildings and automobiles, and used for cable news networks to support real-time graphics. Some car companies, most prominently including

Rivian Rivian Automotive, Inc., is an American electric vehicle manufacturer and automotive technology company founded in 2009. Rivian produces an electric sport utility vehicle (SUV), a pickup truck on a Skateboard (automotive platform), "skateboard" ...

, use Unreal Engine in their

infotainment Infotainment (a portmanteau of ''information'' and ''entertainment''), also called soft news as a way to distinguish it from serious journalism or hard news, is a type of media, usually television or online, that provides a combination of inform ...

systems.

In March 2012, Epic Games announced a partnership with

Virtual Heroes Virtual Heroes, Inc. is a Video game developer, developer of serious games in Raleigh, North Carolina, United States. It was founded in 2004. Virtual Heroes' initial projects focused on creating new technology and content for the U.S. Army game '' ...

Applied Research Associates Applied Research Associates Inc. (ARA), is an engineering, management, and public sector consulting firm and a research and development company headquartered in Albuquerque, New Mexico, founded in 1979. As of 2018, its revenue was estimated at be ...

to launch ''Unreal Government Network'', a program that handles Unreal Engine licenses for government agencies. Several projects originated with this support agreement, including an anaesthesiology training software for

U.S. Army The United States Army (USA) is the primary land service branch of the United States Department of Defense. It is designated as the Army of the United States in the United States Constitution.Article II, section 2, clause 1 of the United Stat ...

physicians, a multiplayer crime scene simulation developed by the FBI Academy, and various applications for the

Intelligence Advanced Research Projects Activity The Intelligence Advanced Research Projects Activity (IARPA) is an organization, within the Office of the Director of National Intelligence (ODNI), that is responsible for leading research to overcome difficult challenges facing the United Stat ...

with the aim to help intelligence analysts recognize and mitigate cognitive biases that might affect their work. Similarly, the

DHS Science and Technology Directorate The Science and Technology Directorate (S&T) is a component within the United States Department of Homeland Security. DHS-S&T serves as the research and development arm of the Department as it fulfills its national security mission. The Science ...

and the U.S. Army's

Training and Doctrine Command The United States Army Training and Doctrine Command (TRADOC) is a major command of the United States Army headquartered at Fort Eustis, Virginia. It is charged with overseeing training of Army forces and the development of operational doctrine. ...

and

Research Laboratory A research institute, research centre, or research organization is an establishment founded for doing research. Research institutes may specialize in basic research or may be oriented to applied research. Although the term often implies natural ...

employed the engine to develop a platform to train

first responders A first responder is a person with specialized training who is among the first to arrive and provide assistance or incident resolution at the scene of an emergency. First responders typically include law enforcement officers (commonly known as ...

titled ''Enhanced Dynamic Geo-Social Environment'' (EDGE).

Awards

The engine has received numerous awards: *

Technology & Engineering Emmy Award The Technology and Engineering Emmy Awards, or Technology and Engineering Emmys, are one of two sets of Emmy Awards that are presented for outstanding achievement in engineering development in the television industry. The Technology and Engineer ...

from the

National Academy of Television Arts and Sciences The National Academy of Television Arts and Sciences (NATAS), also known as the National Television Academy until 2007, is an American professional service organization founded in 1955 for "the advancement of the arts and sciences of televisio ...

(NATAS) for "3D Engine Software for the Production of Animation" in 2018 *

Primetime Engineering Emmy Award The Primetime Engineering Emmy Awards, or Engineering Emmys, are one of two sets of Emmy Awards that are presented for outstanding achievement in engineering development in the television industry. The Primetime Engineering Emmys are presented by ...

from the Television Academy for exceptional developments in broadcast technology in 2020 *

Annie Award The Annie Awards are accolades which the Los Angeles branch of the International Animated Film Association, ASIFA-Hollywood, has presented each year since 1972 to recognize excellence in animation shown in American cinema and television. Origina ...

from

ASIFA-Hollywood ASIFA-Hollywood, an American non-profit organization in Los Angeles, California, is a branch member of the International Animated Film Association. Its purpose is to promote the art of film animation in a variety of ways, including its own arc ...

for technical advancement in animation in 2021 * '' Game Developer Magazine'' Front Line Award for Best Game Engine for 2004, 2005, 2006, 2007, 2009, 2010, 2011, and 2012 * Develop Industry Excellence Award for Best Engine for 2009, 2010, 2011, 2013, 2016, 2017, and 2018 * ''

Guinness World Record ''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a British reference book published annually, listi ...

'' for most successful video game engine in 2014.

Legal aspects

The state of the Unreal Engine came up in Epic's 2020 legal action against

Apple Inc. Apple Inc. is an American multinational corporation and technology company headquartered in Cupertino, California, in Silicon Valley. It is best known for its consumer electronics, software, and services. Founded in 1976 as Apple Comput ...

claiming anticompetitive behavior in Apple's iOS App Store. Epic had uploaded a version of ''

'' that violated Apple's App Store allowances. Apple, in response, removed the ''Fortnite'' app and later threatened to terminate Epic's developer accounts which would have prevented Epic from updating the Unreal Engine for iOS and macOS. The court agreed to grant Epic a permanent injunction against Apple to prevent Apple from taking this step, since the court agreed that would impact numerous third-party developers that rely on the Unreal Engine.