Unreal Engine is a game engine developed by Epic Games, first showcased in the 1998 first-person shooter game Unreal. Initially developed for PC first-person shooters, it has since been used in a variety of genres of three-dimensional (3D) games and has seen adoption by other industries, most notably the film and television industry.
The latest generation is Unreal Engine 4, which was launched in 2014 under a subscription model. Since 2015, it can be downloaded for free, with its source code available on a GitHub private repository. On May 13, 2020, Epic announced that their portion of royalties for games developed in Unreal Engine. Epic allows for its use in commercial products based on a royalty model, typically asking developers for 5% of revenues from sales, though Epic waives this fee for developers that publish their games through the Epic Games Store.
Epic Game Store earned their first US$1 million in revenue, retroactively applying to January 1, 2020. Unreal Engine 5 is scheduled for full release in early 2022.
The first-generation Unreal Engine was developed by Tim Sweeney, the founder of Epic Games. Having created editing tools for the shareware games ZZT (1991) and Jill of the Jungle (1992),[5] Sweeney began writing the engine in 1995 for the production of a game that would later become a first-person shooter known as Unreal. According to an interview, Sweeney wrote 90 percent of the code in the engine, including the graphics, tools, and networking.
Unreal has done an important thing in pushing toward direct color, and this gives the artists a lot more freedom," he said in an article written by Geoff Keighley for GameSpot. "Light blooms [the spheres of light], fog volumes, and composite skies were steps I was planning on taking, but Epic got there first with Unreal," he said, adding: "The Unreal engine has raised the bar on what action gamers expect from future products. The visual effects first seen in the game will become expected from future games."
In October 1998, IGN reported, based on an interview with affiliate Voodoo Extreme, that Sweeney was doing research for his next-generation engine. the second version made its debut in 2002 with America's Army, a free multiplayer shooter developed by the U.S. Army as a recruitment device.
Though based on its predecessor, this generation saw a notable advance in rendering terms as well as new improvements to the tool set. Capable of running levels nearly 100 times more detailed than those found in Unreal, the engine integrated a variety of features, including a cinematic editing tool, particle systems, export plug-ins for 3D Studio Max and Maya, and a skeletal animation system first showcased in the PlayStation 2 version of Unreal Tournament.
With Unreal Tournament 2004, vehicle-based gameplay was successfully implemented, enabling large-scale combat.
While Unreal Tournament 2003 had support for vehicle physics through the Karma engine, as demonstrated by a testmap with a "hastily-constructed vehicle".
In March 2011, Ubisoft Montreal revealed that UE2 was successfully running on the Nintendo 3DS via Tom Clancy's Splinter Cell 3D.
July 2004, Unreal Engine 3 was designed to take advantage of fully programmable shader hardware. All lighting and shadowing calculations were done per-pixel, instead of per-vertex. On the rendering side, Unreal Engine 3 provided support for a gamma-correct high-dynamic range renderer.
Initially, Unreal Engine 3 only supported Windows, PlayStation 3, and Xbox 360 platforms, while iOS (first demonstrated with Epic Citadel) and Android were added later in 2010, with Infinity Blade being the first iOS title and Dungeon Defenders the first Android title.
In 2011, it was announced that the engine would support Adobe Flash Player 11 through the Stage 3D hardware-accelerated APIs and that it was being used in two Wii U games, Batman: Arkham City and Aliens: Colonial Marines.
In 2013, Epic teamed-up with Mozilla to bring Unreal Engine 3 to the web; using the asm.js sublanguage and Emscripten compiler, they were able to port the engine in four days.
While Unreal Engine 3 was quite open for modders to work with, the ability to publish and sell games meant using UE3 was restricted to licenses of the engine. However, in November 2009, Epic released a free version of UE3's SDK, called the Unreal Development Kit (UDK), that is available to the general public.
In December 2010, the kit was updated to include support for creating iOS games and apps. OS X compatibility followed in the September 2011 release.
In August 2005, Mark Rein, the vice-president of Epic Games, revealed that Unreal Engine 4 had been in development for two years. It certainly doesn't have a full team yet, it's just one guy and you can probably guess who that guy is," he told C&VG. Sweeney stated that he was basically the only person working on the engine, though he affirmed his research and development department would start to expand later that year, designing the engine in parallel with the efforts by the UE3 team.
In February 2012, Rein said "people are going to be shocked later this year when they see Unreal Engine 4". Epic unveiled UE4 to limited attendees at the 2012 Game Developers Conference,and a video of the engine being demonstrated by technical artist Alan Willard was released to the public on June 7, 2012, via GameTrailers TV.
One of the major features planned for UE4 was real-time global illumination using voxel cone tracing, eliminating pre-computed lighting. However, this feature, called Sparse Voxel Octree Global Illumination (SVOGI) and showcased with the Elemental demo, was replaced with a similar but less computationally expensive algorithm due to performance concerns.
The first game released using Unreal Engine 4 was Daylight, developed with early access to the engine and released on April 29, 2014.
On September 4, 2014, Epic released Unreal Engine 4 to schools and universities for free, including personal copies for students enrolled in accredited video game development, computer science, art, architecture, simulation, and visualization programs.
On February 19, 2015, Epic launched Unreal Dev Grants, a $5 million development fund aiming to provide grants to creative projects using Unreal Engine 4.
In March 2015, Epic released Unreal Engine 4, along with all future updates, for free for all users.
Sweeney stated that when they moved to the subscription model in 2014, use of Unreal grew by 10 times and through many smaller developers, and believed that they would draw even more uses through this new pricing scheme.
The engine officially supports the following platforms as of 4.27:
Unreal Engine 5 was revealed on May 13, 2020, supporting all existing systems including the next-generation consoles PlayStation 5 and Xbox Series X/S. It was released in early access on May 26, 2021, with expected full launch in early 2022.
The Nanite virtualized geometry technology allows Epic to take advantage of its past acquisition of Quixel, the world's largest photogrammetry library as of 2019. The goal of Unreal Engine 5 was to make it as easy as possible for developers to create detailed game worlds without having to spend excessive time on creating new detailed assets, allowing the engine software to handle these factors.
Epic had worked closely with Sony in optimizing Unreal Engine 5 for the PlayStation 5, with Epic collaborating with Sony on the console's storage architecture. To demonstrate the ease of creating a detailed world with minimal effort, the May 2020 reveal of the engine showcased a demo called "Lumen in the Land of Nanite" running on a PlayStation 5 that was built mostly by pulling assets from the Quixel library and using the Nanite, Lumen, and other Unreal Engine 5 components to create a photorealistic cave setting that could be explored.
Additional features planned for Unreal Engine 5 come from Epic's acquisitions and partnerships. The MetaHuman Creator is a project based on technology from three companies acquired by Epic, 3Lateral, Cubic Motion, and Quixel, to allow developers to quickly create realistic human characters that can then be exported for use within Unreal. Through partnership with Cesium, Epic plans to offer a free plugin to provide 3D geospatial data for Unreal users, allowing them to recreate any part of the mapped surface of Earth.
Epic will include Reality Capture, a product it acquired with its acquisition of Capturing Reality that can generate 3D models of any object from a collection of photographs taken of it from multiple angles, and the various middleware tools offered by RAD Game Tools.
Unreal Engine 5 will retain the current royalty model, with developers returning 5% of gross revenues to Epic Games, though this fee is forgiven for those that release their games on the Epic Games Store. Further, Epic announced alongside Unreal Engine 5 that they will not take any fee from games using any version of Unreal Engine for the first US$1 million in gross revenue, retroactive to January 1, 2020.
