Unreal Engine

"Unreal technology" redirects here. For science or technology which is beyond reality, see science fiction.

Developer(s)	Epic Games
Initial release	1998 (1998)
Stable release	4.10 / 11 November 2015 (2015-11-11)
Available in	English, Korean, Chinese, Japanese
Type	Game engine
Website	unrealengine.com

The Unreal Engine is a game engine developed by Epic Games, first showcased in the 1998 first-person shooter game Unreal. Although primarily developed for first-person shooters, it has been successfully used in a variety of other genres, including stealth, MMORPGs, and other RPGs. With its code written in C++, the Unreal Engine features a high degree of portability and is a tool used by many game developers today.

The current release is Unreal Engine 4, designed for Microsoft's DirectX 11 and 12 (for Microsoft Windows, Xbox One, Windows RT); OpenGL (for OS X, Linux, PlayStation 4, iOS, Android, Ouya and Windows XP); and JavaScript/WebGL (for HTML5 Web browsers).

Versions

Unreal Engine 1

File:Unreal-GlideVoodoo1flyby.jpg

Unreal was the first game using the Unreal Engine.

Unreal Engine 1

Initial release	Unreal build 100 / May 1998
Stable release	Unreal Tournament build 436 / November 2000
Written in	C++ , UnrealScript, Assembly
Platform	Microsoft Windows, Linux, Mac OS and OS X, Dreamcast, PlayStation 2
License	Proprietary
Website	www.unrealengine.com

Making its debut in 1998 with Unreal, the first generation Unreal Engine integrated rendering, collision detection, AI, visibility, networking, scripting, and file system management into one complete engine. Unreal Engine 1 provided an advanced software rasterizer and a hardware-accelerated rendering path using the Glide API, specifically developed for 3dfx GPUs, and was updated for OpenGL and Direct3D. Large parts of the game were implemented in a custom scripting language called UnrealScript. Epic used this engine for both Unreal and Unreal Tournament. The release of Unreal Tournament marked great strides in both network performance and Direct3D and OpenGL support.

The engine became popular due to the modular engine architecture and the inclusion of a scripting language, which made it easy to mod, including total conversions like Tactical Ops.

From the start the engine was designed in a way to be extensible and improved over multiple generations of games, as creator and founder of Epic Games Tim Sweeney states in a 1998 interview with magazine Maximum PC:

The big goal with the Unreal technology all long was to build up a base of code that could be extended and improved through many generations of games. Meeting that goal required keeping the technology quite general-purpose, writing clean code, and designing the engine to be very extensible. The early plans to design an extensible multi-generational engine happened to give us a great advantage in licensing the technology as it reached completion. After we did a couple of licensing deals, we realised it was a legitimate business. Since then, it has become a major component of our strategy.

— Tim Sweeney, interview with Maximum PC

Unreal Engine 2

Killing Floor was built in Unreal Engine 2.

Unreal Engine 2

Initial release	Unreal Warfare build 633 / January 2001
Stable release	Unreal Engine 2.5 build 3369 / November 2005
Written in	C++ , UnrealScript
Platform	Microsoft Windows, Linux, OS X, Xbox, PlayStation 2, GameCube
License	Proprietary
Website	www.unrealengine.com

The second version made its debut in 2002 with America's Army, a free multiplayer shooter created and funded by the US Army. This generation saw the core code and rendering engine completely re-written. In addition, it featured UnrealEd 2, which debuted with the previous generation of the engine and was shortly followed later by UnrealEd 3, along with the Karma physics SDK. This physics engine powered the ragdoll physics in Unreal Tournament 2003 and Unreal Championship. Other engine elements were also updated, with improved assets as well as adding support for the GameCube and the Xbox. Support for the PlayStation 2 console was previously added in UE1. Taking Xbox aside, both GameCube and PS2 were never supported directly by Epic, support being instead farmed out to Secret Level said builds were stale and left behind, the last "official" build PS2 and GC saw was build 927 dated April 2002; last official UE2.5 build was build 3369. As such, third parties looking to use further Unreal Engine revisions had to do their own builds throughout the generation, as they had to in more recent years with the Wii, X360, PS3, PSP, and 3DS.

UE2.5, an update to the original version of UE2, improved rendering performance and added vehicles physics, a particle system editor for UnrealEd, and 64-bit support in Unreal Tournament 2004. A specialized version of UE2.5 called UE2X was used for Unreal Championship 2: The Liandri Conflict on the original Xbox platform. It featured optimizations specific to that console. EAX 3.0 is also supported for sound. Unreal Engine 2.X was build 2227, dated March 2004.

On March 23, 2011, Ubisoft Montreal revealed that UE2.5 was successfully running on the Nintendo 3DS.

Unreal Engine 3

BioShock Infinite was built in Unreal Engine 3

Unreal Engine 3

Initial release	Unreal Engine 3 build 100 / March 2004
Stable release	Unreal Engine 3 build 12791.2424394 / February 2015
Written in	C++, C#, UnrealScript, GLSL, Cg, HLSL
Platform	Microsoft Windows, Linux, OS X, Xbox 360, Xbox One, PlayStation 3, PlayStation 4, Wii U, Android, iOS, Windows RT, and PlayStation Vita, Adobe Flash Player, HTML5
License	Proprietary
Website	www.unrealengine.com

The first screenshots of Unreal Engine 3 were presented in 2004, at which point the engine had already been in development for 18 months. Unlike Unreal Engine 2, which still supported fixed-function pipeline, Unreal Engine 3 was designed to take advantage of fully programmable shader hardware (in DirectX 9 terms, it required shader model 3.0). All lighting calculations were done per-pixel, instead of per-vertex. On the rendering side, Unreal Engine 3 also provided support for a gamma-correct high-dynamic range renderer. UE3 expected that content was authored in both high- and low-resolution version and baked normal maps for run-time; a major difference to previous generations where the game content was modeled directly (since normal mapping is a per-pixel operation and almost all the dynamic lighting in UE1 and 2 was calculated per-vertex using a Gouraud Shading technique)

The third generation of the Unreal Engine is designed for DirectX (versions 9-11 for Windows, Windows RT and Xbox 360), as well as systems using OpenGL, including the OS X, iOS, Android, Stage 3D for Adobe Flash Player 11, and JavaScript/WebGL for HTML5 Web Browsers. Initially, Unreal Engine 3 only supported Windows, Xbox 360, and PlayStation 3 platforms, while Android and iOS were added later in 2010 (with Infinity Blade being the first iOS title and Dungeon Defenders the first Android title). OS X support was added in 2011. Its renderer supports many advanced techniques including HDRR, per-pixel lighting, and dynamic shadows. It also builds on the tools available in previous versions. In October 2011, the engine was ported to support Adobe Flash Player 11 through the Stage 3D hardware-accelerated APIs. Epic has used this version of the engine for their in-house games. Aggressive licensing of this iteration has garnered a great deal of support from many prominent licensees. Epic has announced that Unreal Engine 3 runs on both Windows 8 and Windows RT. The first released console game using Unreal Engine 3 was Gears of War and the first released PC game was RoboBlitz.

In addition to the game industry, UE3 has also seen adoption by many non-gaming projects, for instance:

• The popular children's TV show LazyTown used UE3 during filming to generate virtual sets for real-time integration with footage of actors and puppets performing in front of green screens.
• In March 2012, the FBI licensed Epic's Unreal Engine 3 to use in a simulator for training.
• The animation software "Muvizu Play", which was released in April 2013, uses UE3.

Unreal Development Kit

The Ball was built in the UDK.

Unreal Development Kit

Initial release	v5860 / November 2009
Stable release	v12791.2424394 / February 2015
Written in	C++, C#, UnrealScript, GLSL, Cg, HLSL
Operating system	Microsoft Windows
Platform	Microsoft Windows, OS X, iOS
Type	Level editor / Software development kit
License	Free for noncommercial use
Website	UDK website UDN for UDK

While Unreal Engine 3 has been quite open for modders to work with, the ability to publish and sell games made using UE3 was restricted to licensees 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. According to the current EULA, game developers can sell their games by paying Epic the cost of $99 USD, and 25% royalty on UDK related revenue above US$50,000 from all UDK-based games or commercial applications.

The December 2010 UDK release added support for creating iOS games and apps. UDK's iOS development feature set includes:

• The full source and content for Epic Citadel, plus an additional castle demo map.
• Support for major Unreal Engine 3 desktop features, including the Unreal Editor and its fully integrated suite of tools including Unreal Kismet, Unreal Cascade and Unreal Matinee.
• Superior rendering systems, including Unreal Lightmass global illumination supported by Unreal Swarm distributed computing.
• Content streaming functionality.
• Advanced lighting and shadowing such as per-pixel lighting and real-time shadows.
• Console-quality capabilities.
• Full Unreal Kismet visual scripting functionality, which allows the developers to create games without having to modify program code.
• Convenient mobile previewer makes it possible to emulate games at native resolution for quick iteration.
• UDK Remote enables iOS devices to serve as wireless controllers with full touch and tilt functionality for testing games on the computer.

As of the September 2011 release, iOS, OS X and Windows platforms all support UDK-created games.

Updates

File:Unreal Engine Comparison.jpg

A comparison of Unreal Engine 1, 2, and 3's rendering capabilities using the Malcolm model from Unreal Tournament, Unreal Tournament 2004, and Unreal Tournament 3 side-by-side.

Throughout the lifetime of UE3, significant updates have been incorporated:

• Epic Games announced at Game Developers Conference (GDC) 2009 some improvements made to Unreal Engine 3. These included:
  • Unreal Lightmass: a global illumination solver. Provides high-quality static lighting with next-generation effects, such as soft shadows with accurate penumbrae, diffuse, specular inter-reflection, and color bleeding.
  • The ability to add fracture effects to static meshes to simulate destructible environments
  • Soft body dynamics (physics)
  • Large crowd simulation
• In December 2009, Epic demoed UE3 running on Apple's 3rd generation iPod Touch. They said that this will also support iPhone 3GS, and also an unknown mobile platform which has been revealed to be webOS at CES 2010. It has been revealed so far to be something on Nvidia's Tegra platform, and also Palm's webOS running PowerVR's SGX chip.
• In March 2010, Steamworks was integrated into the software, and is offered to licensees.
• In June 2010, Epic Games revealed Epic Citadel, a tech demo to showcase Unreal Engine 3 on iOS devices (iPhone, iPod touch, and iPad devices).
• In June 2010 during the Electronic Entertainment Expo 2010, Mark Rein (vice president of Epic Games) showcased a tech demo of Gears of War 2 in stereoscopic 3D running on an Xbox 360 thanks to the TriOviz for Games Technology. "This technology's great because it works on normal HD TVs, as well as the very high end 3DTVs," Rein commented to Computer and Video Games. "We're not planning to re-release this in 3D – unless Microsoft want us to – but I'm sure it's technology may be keen to put in the games developed by our partners."
• In October 2010, TriOviz for Games Technology has been officially integrated in Unreal Engine 3, allowing to easily convert in stereoscopic 3D, numerous past and upcoming games developed on Xbox 360 and PS3 with this engine.
• As of March 2011, the Unreal 3 Engine supports DirectX 11. Epic Games showcased it with a real-time demonstration video, entitled "Samaritan". Additions include tessellation and displacement mapping, advanced hair rendering with MSAA, deferred shading with MSAA, screen space subsurface scattering, image-based lighting, billboard reflections, glossy reflections, reflection shadows, point light reflections, and bokeh depth of field. The Samaritan demo was unveiled during GDC 2011 as a proof of concept and target for the "3.5" version of Epic's Unreal Engine 3, ostensibly aimed at next-generation platforms. It was built by Epic Games in a close partnership with NVIDIA, with engineers working around the country to push real-time graphics to a new high point.
• In July 2011, Geomerics announced that their real-time global illumination solution Enlighten is now integrated with Unreal Engine 3 and available to licensees.
• In October 2011, Epic Games announced that a version of the engine would be compatible with Adobe Flash Player.
• In May 2012, UE3 added support for the RealD 3D stereoscopic technology.
• In March 2013, Mozilla and Epic Games have demonstrated UE3 running on the browser using HTML5 and JavaScript technologies.

Unreal Engine 4

Unreal Tournament is being built with Unreal Engine 4.

Unreal Engine 4

Initial release	Unreal Engine 4 build 8967 / May 2012
Stable release	Unreal Engine 4.10 / November 11, 2015
Written in	C++, C#, GLSL, Cg, HLSL; UnrealScript removed
Platform	Microsoft Windows, Linux, OS X, Xbox One, PlayStation 4, HTML5, iOS, Android, Oculus Rift, Ouya, HTC Vive
License	Free to use, with access to source code; 5% royalty after first $3000USD per quarter
Website	www.unrealengine.com

On August 17, 2005, Mark Rein, the vice-president of Epic Games, revealed that Unreal Engine 4 had been in development since 2003. Until mid-2008, development was exclusively done by Tim Sweeney, CEO and founder of Epic Games. The engine targets the eighth generation of consoles, PCs and Tegra K1-based devices running Android announced in January 2014 at CES.

In February 2012, Mark Rein said "people are going to be shocked later this year when they see Unreal Engine 4". Unreal Engine 4 was unveiled to limited attendees at the 2012 Game Developers Conference, and video of the engine being demonstrated by technical artist Alan "Talisman" Willard was released to the public on June 7, 2012 via GameTrailers TV. This demo was created on a PC with triple GeForce GTX 580 (tri SLI) and can be run on a PC with a GeForce GTX 680.

One of the major features planned for UE4 was real-time global illumination using voxel cone tracing, eliminating pre-computed lighting. However, this feature has been replaced with a similar but less computationally-expensive algorithm prior to release for all platforms including the PC because of performance concerns on next-generation consoles. UE4 also includes new developer features to reduce iteration time, and allows updating of C++ code while the engine is running. The new "Blueprint" visual scripting system (a successor to UE3's "Kismet") allows for rapid development of game logic without using C++, and includes live debugging. The result is reduced iteration time, and less of a divide between technical artists, designers, and programmers.

[In older engines], if you wanted to change the relationship between your weapon damage and how long it'll take to kill a creature, you may spend a couple of days iterating, but if you have to spend a lot of time waiting for a build every time, you're talking one change, waiting 15 minutes for the compile to complete, and then play the game, get to the point where you can test it, test it, exit the game, change, compile... Now, since all of that can be done very quickly within the tools, it's 'Make the change, play, when it compiles, finish, shoot the guy, and then escape, make the change, play'. The iteration time is down to 30 seconds instead of 15 minutes. Our ability to kind of roll through and see how the game is playing out is much faster.

— Alan Willard, writing for Kotaku

On March 19, 2014, at the Game Developers Conference, Epic Games released Unreal Engine 4, and all of its tools, features and complete C++ source code, to the development community through a new subscription model. Anyone can sign up for UE4 for Windows, OS X, iOS and Android by paying $19 per month, plus 5% of gross revenue resulting from any commercial products built using UE4. CEO and founder of Epic Games, Tim Sweeney, said that the new business model is a reflection of changes in the industry. Epic Games has traditionally made its Unreal Engine available to large AAA game development teams at a cost of millions of dollars but as the industry has evolved, Epic has had to "really rethink our whole business as to how we make the engine available to teams." "Looking at the new shape of the industry now, we realize that's an outdated tool," Sweeney said. "Looking at the possibilities for the engine, we started from scratch and thought 'How can we make the engine available to more people?'". According to the Unreal Engine website, subscribers to the engine will be able to cancel their subscription, or renew it at any time. They will be able to retain access to UE4 tools, but will not receive access to future releases of Unreal Engine 4.

Interactive architectural visualization using Unreal Engine 4. Created by UE4Arch.com

On September 3, 2014, Epic Games launched the Unreal Engine Marketplace, allowing UE4 subscribers to buy and sell community-created content of all shapes and sizes. In addition to all of the previously released free content, the new marketplace came with a variety of asset packs including full-scale environments, props, characters, sounds, materials, animated meshes, prefab C++ code and a number of other asset types as well as free demos and tutorials.

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. "Nothing is stopping students from honing the skills needed to enter the range of fields using Unreal Engine technology, from entertainment software and film to visualization, healthcare simulation and military training," Unreal Engine general manager Ray Davis said in a statement. "Students who know Unreal Engine technology have a huge advantage when it comes to job placement." Schools can integrate the same fully featured version of Unreal Engine 4 previously available only to developers, along with all future updates. In addition, students retain indefinite access to any versions of the engine used during their coursework which gives them the option to turn their class projects into shipping projects at any time.

On February 19, 2015, Epic launched Unreal Dev Grants, a $5,000,000 development fund designed to provide financial grants to innovative projects being built with Unreal Engine 4. Awards range from $5,000 to $50,000, with no strings attached: developers and artists own their IP and are free to publish however they wish, with no restrictions or obligations on the way the funds are used.

As of March 2, 2015, Unreal Engine 4 is available to everyone for free, and all future updates will be free. Epic will be issuing a pro-rated refund to people who have paid for Unreal Engine 4 since January 31, 2015. In addition, anyone who has ever paid for an UE4 subscription will receive a $30 credit for the Unreal Engine Marketplace. If projects are released commercially, developers must pay a 5% royalty on gross revenue following the first $3,000 per product, per quarter.

In 2015, Armature Studio has announced that it will be responsible for porting Bloodstained: Ritual of the Night to the PS Vita and Wii U. This will include porting Unreal Engine 4 to those platforms, as they are not officially supported by Epic Games. Armature will make their engine code available to licensed Wii U and PS Vita developers after Bloodstained is finished.

Make Something Unreal

Main article: Make Something Unreal

In the Make Something Unreal Contest, aspiring game developers created modifications (mods) in a range of categories including levels, characters, vehicles, gametypes, machinima and more. Exceeding $1 million in value, winnings consisted of Unreal Engine commercial licenses, over $500,000 in cash awards and additional hardware prizes. The MSUC, which began in 2004 with subsequent competitions in 2008, 2012, and 2013, was judged in four preliminary phases and a grand final.

Games using the Unreal Engine

Main article: List of Unreal Engine games

Awards and accolades

Unreal Engine 3

• Game Developer Magazine Front Line Awards

- "Best Game Engine" (2004, 2005, 2006, 2007, Hall of Fame, 2009, 2010, 2011, 2012)

• IGN's Best of E3 2005

- "Best Graphics Technology (Xbox 360)"

- "Technological Excellence"

• North Carolina Technology Association 21 Awards

- "Top Industry Driven Technology of the Year" (2008, 2011)

- "Best Product or Service" (2012)

• Develop Industry Excellence Awards

- "Best Game Engine" (2009, 2010, 2011)

Unreal Engine 4

• GamesRadar's E3 2012 Important Stuff Awards

- "Best Taste of Next-Gen"

• IGN's Best of E3 2012

- "Coolest Tech"

• Game Informer's Best of E3 2012 Awards

- "Best Tech"

• Develop Industry Excellence Awards 2013

- "Best Game Engine"

• Develop 100: The Tech List 2014

- "Best Game Engine"

Other licensees

Unreal Engine 3

Licenses for education

• PEPFAR/Warner Brothers
• Norwich University of the Arts
• The Jim Henson Company
• University of Advancing Technology
• Louisiana State University in Shreveport
• Centennial College
• Ex'pression College for Digital Arts
• Digital Media Arts College
• The Art Institute of California
• University of Bournemouth
• Stanly Community College
• University of Teesside
• San Jacinto College South
• University of Wisconsin Stout
• Indiana University – Purdue University Indianapolis
• University of Derby
• Singapore Polytechnic

Licenses for Training Simulation

• U.S. Army
• U.S. Air Force
• NASA
• Federal Bureau of Investigation (FBI)
• Michigan Department of Transportation (MDOT)
• U.S Department of Homeland Security (DHS)
• Virtual Heroes, a division of Applied Research Associates, Inc.
• IPKeys Technologies/Improvised Explosive Device (IED) Gaming and Modeling Environment (I-GAME)

Licenses for Construction Simulation

• HKS, Inc.

Licenses for VR Techniques

• Yost Engineering, Inc/YEI Technology

Licenses for CG animation

• HDFilms
• Just Cause Entertainment
• House of Moves
• Reed + Rader
• LightHammer
• Glasgow’s DA Group
• Raymond P. Le Gué

Unreal Engine 4

Licenses for education

• Andrews University
• Atlantic University College
• Coleman University
• Columbia College Chicago
• Doña Ana Community College
• East Tennessee State University
• Florida Interactive Entertainment Academy
• Florida Southern College
• Foothill College
• George Mason University
• Oklahoma Christian University
• Penn State Behrend
• Richland College
• San Jose State University
• Savannah College of Art and Design
• Southern Methodist University's Guildhall
• Staffordshire University
• St. Edward's University
• The Art Institute of Seattle
• Tyler Junior College
• University of Advancing Technology
• University of Central Florida
• University of Houston
• University of Michigan–Dearborn
• Wake Technical Community College
• Whitworth University

UnrealScript

UnrealScript

Paradigm	Object-oriented, generic
Developer	Tim Sweeney
First appeared	1998
Typing discipline	Static, strong, safe
OS	Cross-platform (multi-platform)
Filename extensions	.uc .uci .upkg
Website	udn.epicgames.com
Influenced by
C++, Java

UnrealScript (often abbreviated to UScript) is Unreal Engine's native scripting language used for authoring game code and gameplay events before the release of Unreal Engine 4. The language was designed for simple, high-level game programming. The UnrealScript interpreter was programmed by Tim Sweeney, who also created an earlier game scripting language, ZZT-oop.

Similar to Java, UnrealScript is object-oriented without multiple inheritance (classes all inherit from a common Object class), and classes are defined in individual files named for the class they define. Unlike Java, UnrealScript does not have object wrappers for primitive types. Interfaces are only supported in Unreal Engine generation 3 and a few Unreal Engine 2 games. UnrealScript supports operator overloading, but not method overloading, except for optional parameters. By making the process of modifying games easier, UnrealScript helped enable the growth of a large modding community around the Unreal series. This greatly added to the overall longevity of Unreal and provided an incentive for new development.

Syntax

Code comments

UnrealScript uses two commenting styles, a single-line comment (beginning with // until the end of the line) and a multi-line comment (delimited by /* and */).

// Single-line comment
class Foo extends Object;

/* Multi-line
   comment */
var Object Foo;

Data types

Primitive types

• Bool - A boolean that allows the values true, and false, which are the same to 1 and 0
• Byte - An unsigned 8-bit integer value
• Enum
• Float
• Int - A signed 32-bit integer value
• Name - A more restricted version of String, only allowing the following characters ([a-zA-Z0-9_\- ]*) as expressed in regex. e.g. 'name_example'
• String - A series of Unicode characters such as "A B C"

Reference types

• Class
• Delegate
• Interface
• Object
• Pointer

Composite types

• Array
• Struct

Functions

UnrealScript uses functions similar to C/C++/Java. Functions are declared by the keyword: function, followed by an optional return type, its required name, and finally its function parameters.

The declaration of a function can look like this:

[modifiers] function [[modifiers] datatype] name( [parameters] ) [const]; the semicolon is only necessary if the function has no body.

An example of a very simple additive function in UnrealScript:

function int Add( int a, int b )
{
    return a + b;
}

"Hello, world" example

The following is a hello world example using the syntax of UnrealScript.

class HelloWorld extends GameInfo;

event InitGame( string Options, out string Error )
{
    `log( "Hello, world!" );
}

The following text will be printed to the output console when HelloWorld is initializing:

Hello, world!

Unreal Editor

File:UnrealEd10.jpg

Screenshot of UnrealEd 1.0

Unreal Editor, also called UnrealEd, is the level editor used to create levels for the Unreal series. It was also used for other games based on the Unreal Engine, such as Deus Ex and Lineage II, although it has changed along with the engine for later games. All Unreal games on the PC had the level editor included for free, and some third party Unreal engine games did the same with an edited and specialized version. This extended the longevity of the games. Amateur level designers could now create their own levels for the game, providing a near endless amount of additional content for the game. In addition, the built-in scripting language called UnrealScript allowed for editors to customize game content.

Further reading

• Keith Stuart (December 2009). The hidden story of the 3D engine - by the people who write them. How programming masters like Tim Sweeney built the engineering marvels of the 21st century.... The Guardian
• Mike Thomsen (February 2010). History of the Unreal Engine. The Epic evolution of gaming's most influential engine, from Gears Of War to Mass Effect 2. IGN
• John Gaudiosi (September 2011). Epic Games Founder Tim Sweeney Pushes Unreal Engine 3 Technology Forward. Forbes
• Stu Horvath (May 2012). The Imagination Engine: Why Next-Gen Videogames Will Rock Your World. Wired
• Dave Thier (June 2012). Epic's Tim Sweeney on How Unreal Engine 4 Will Change The Way Games Are Made, and Why You Care. Epic’s new engine could halve production costs, lower the prices of games, and spur détente between developers and consumers. Forbes
• Brian Steiner (June 2013). How The Unreal Engine Became A Real Gaming Powerhouse. Popular Mechanics
• GamesTM (September 2014). How Unreal Engine is changing for the new generation. GamesTM
• John Gaudiosi (March 2015). Why Epic Games is giving away its game technology. Fortune.
• Chris Plante (March 2015). Why video game engines may power the future of film and architecture. The original developer of Gears of War has an ambitious plan for the future of everything. The Verge.

Tutorials

• John P. Flynt & Chris Caviness (May 2006). UnrealScript Game Programming All in One. Thomson Course Technology. ISBN 978-1-598-63148-7
• Jason Busby, Zak Parrish & Jeff Wilson (July 2009). Mastering Unreal Technology, Volume I: Introduction to Level Design with Unreal Engine 3. Sams Publishing. ISBN 978-0-672-32991-3
• Jason Busby, Zak Parrish & Jeff Wilson (October 2009). Mastering Unreal Technology, Volume II: Advanced Level Design Concepts with Unreal Engine 3. Sams Publishing. ISBN 978-0-672-32992-0
• Ashish Amresh & Alex Okita (August 2010). Unreal Game Development. CRC Press. ISBN 978-1-568-81459-9
• Jason Busby, Zak Parrish & Jeff Wilson (January 2011). Mastering Unreal Technology, Volume III: Introduction to UnrealScript with Unreal Engine 3. Sams Publishing. ISBN 978-0-672-33082-7
• Richard J. Moore (August 2011). Unreal Development Kit 3: Beginner's Guide : a Fun, Quick, Step-by-step Guide to Level Design and Creating Your Own Game World. Packt Publishing. ISBN 978-1-849-69052-2
• Rachel Cordone (December 2011). Unreal Development Kit Game Programming with Unrealscript: Beginner's Guide. Packt Publishing. ISBN 978-1-849-69192-5
• Alan Thorn (December 2011). UDK Game Development. Cengage Learning, Inc.. ISBN 978-1-435-46018-8
• Thomas Mooney (February 2012). Unreal Development Kit Game Design Cookbook. Packt Publishing. ISBN 978-1-849-69180-2
• Robert Chin (April 2012). Beginning iOS 3D Unreal Games Development. Apress Media LLC. ISBN 978-1-430-24035-8
• Heinrich Hußmann (October 2012). "Realtime Interactive Architectural Visualization using Unreal Engine 3.5" (PDF). Ludwig-Maximilians-Universität München.
• John P. Doran (March 2013). Mastering UDK Game Development Hotshot. Packt Publishing. ISBN 978-1-849-69560-2
• Geof Sholler (August 2013). Build a Game with UDK. Packt Publishing. ISBN 978-1-849-69580-0
• Andrew Finch (March 2014). The Unreal Game Engine: A Comprehensive Guide to Creating Playable Levels. 3DTotal Publishing. ISBN 978-1-909-41404-4
• Ryan Shah (June 2014). Master the Art of Unreal Engine 4 - Blueprints. CreateSpace Independent Publishing. ISBN 978-1-500-21310-7

External links

• Official website
• The official Unreal Developer Network (UDN) documenting Unreal Engine 1x-3x
• Unreal Development Kit
• Unreal Engine wiki
• Unreal Engine 3 / UDK tutorials
• Unreal Engine 4 tutorials