Unity (game engine)

Unity

Developer(s)	Unity Technologies
Stable release	3.5 / February 14, 2012
Written in	C++, C#
Operating system	Windows (creation and deployment), Mac OS X (creation and deployment), Wii*, iPhone/iPad*, Xbox 360*, Android*, PS3* * = deployment only; an additional special licence is required for each platform
Type	Game engine
License	Proprietary
Website	www.unity3d.com

Unity is an integrated authoring tool for creating 3D video games or other interactive content such as architectural visualizations or real-time 3D animations. The current release is version 3.5. Unity's development environment runs on Microsoft Windows and Mac OS X, and the games it produces can be run on Windows, Mac, Xbox 360, PlayStation 3, Wii, iPad, iPhone, as well as the Android platform. It can also produce browser games that use the Unity web player plugin, supported on Mac and Windows but not Linux. The web player is also used for deployment as Mac widgets. Unity also has the ability to export games to Adobe's Stage 3D functionality in Flash, but certain features that the web player supports are not useable due to limitations in Flash.

Unity consists of both an editor for developing/designing content and a game engine for executing the final product. Unity is similar to Director, Blender game engine, Virtools, Torque Game Builder, and Gamestudio, which also use an integrated graphical environment as the primary method of development.

Unity won the Wall Street Journal 2010 Technology Innovation Award in the software category. In 2009, Unity Technologies was named one of Gamasutra's "Top 5 Game Companies of 2009" for Unity. Unity was a runner-up for the best use of graphics on Mac OS X in the 2006 Apple Design Awards.

Major features

• Integrated development environment with hierarchical, visual editing, detailed property inspectors and live game preview.
• Deployment on multiple platforms:
  • As a Microsoft Windows or Mac OS X executable
  • On the web (via the Unity Web Player plugin for Internet Explorer, Firefox, Safari, Mozilla, Netscape, Opera, Google Chrome and Camino) on Windows and OS X.
  • As a Mac OS X Dashboard widget
  • For Nintendo Wii (requires additional license)
  • As an iPhone/iPad application (requires additional license)
  • For Google Android (requires additional license)
  • For Microsoft Xbox 360 (requires additional license)
  • For Sony PlayStation 3 (requires additional license)
• Assets loaded into Unity and are automatically imported, and are re-imported if the asset is updated. Unity supports integration with 3ds Max, Maya, Softimage, Blender, Modo, ZBrush, Cinema 4D, Cheetah3D, Photoshop and Allegorithmic Substance.
• Graphics engine uses Direct3D (Windows), OpenGL (Mac, Windows), OpenGL ES (iOS, Android), and proprietary APIs (Wii).
• Support for bump mapping, reflection mapping, parallax mapping, Screen Space Ambient Occlusion, dynamic shadows using shadow maps, render-to-texture and full-screen post processing effects.
• ShaderLab language for using shaders, supporting both declarative "programming" of the fixed-function pipeline and shader programs written in Cg or GLSL. A shader can include multiple variants and a declarative fallback specification, allowing Unity to detect the best variant for the current video card and if none are compatible, fall back to an alternative shader that may sacrifice features for broader compatibility.
• Built-in support for Nvidia's (formerly Ageia's) PhysX physics engine, version 2.8.3 (as of Unity 3.0) with added support for real time cloth on arbitrary and skinned meshes, thick ray casts, and collision layers.
• Game scripting via Mono. Scripting is built on Mono, the open-source implementation of the .NET Framework. Programmers can use UnityScript (a custom language with ECMAScript-inspired syntax), C# or Boo (which has a Python-inspired syntax). Starting with the 3.0 release, Unity ships with a customized version of MonoDevelop for debugging scripts.
• The Unity Asset Server - A version control solution for all game assets and scripts, using PostgreSql as a backend.
• Audio system built on FMOD library, with ability to play back Ogg Vorbis compressed audio.
• Video playback using Theora codec.
• A terrain and vegetation engine, supporting tree billboarding.
• Occlusion Culling with Umbra (only in Unity >= 3 Pro).
• Built-in lightmapping and global illumination with Beast (only in Unity >= 3 Pro).
• Multiplayer networking using Raknet.
• The Unity Asset Store - An in-editor repository with thousands of Unity-ready assets, including models, characters, code, audio, etc.

Unity Asset Server

The Unity Asset Server was a version control solution for all game assets and scripts. It is now superseded by the version control system in Unity 3.5. The asset server supports multi-gigabyte projects with thousands of multi-megabyte files. Import settings and other metadata are stored and versioned while updates, commits, and graphical version comparisons are all performed inside the Unity Editor. When files are modified, their status is updated instantly. The Unity Asset Server runs on the open source PostgreSQL database server and is available for Windows, Mac OS X and Linux. It lacks support for branches, and obviously for branch merges.

Although the software that is used to run a Unity Asset Server is itself free to download and use, a connection to a Unity Asset Server cannot be made without a copy of the Unity3D Pro client that includes the Asset Server add-on, which is an additional cost.

Licensing

There are two main licenses: Unity and Unity Pro, with the Pro version being available for a price and the non Pro version being free. The Pro version has additional features, such as render-to-texture, occlusion culling, global lighting and post-processing effects. The Free version, on the other hand, displays a splash screen (in standalone games) and a watermark (in web games) that cannot be customized or disabled.

Both Unity and Unity Pro include the development environment, tutorials, sample projects and content, support via forum, wiki, and future updates in the same major version (i.e. buying Unity Pro 3.0 gets all future Unity Pro 3.x updates for free).

Unity for iOS and Unity for Android are add-ons to an existing Unity purchase. A Unity Pro licenses is required to purchase an iOS Pro or Android Pro licenses. The regular Android and iOS licenses can be used with the free version of Unity.

Source code, PS3, Xbox 360, and Wii licenses are negotiated on a case by case basis.

Educational licenses are provided by Studica with the stipulation that it is for purchase and use by schools, purely for education.

Future platforms

Flash

It was announced in February 2011 that Unity will export to Adobe Flash at some point in the future. Version 3.5 Beta includes a developer preview of the feature, but development is ongoing. This will allow users to play Unity-authored content with a Flash browser plug-in, rather than need to install the Unity plug-in, provided the game developer has built a Flash version of their game. Features are to include physics, lightmapping, Occlusion culling, custom shaders, lightprobes, particle systems, audio, and communication between the Unity project and Actionscript code.

Google Chrome Native Client

It was announced in 2010 that Unity Technologies was working on a Native Client port of their engine for Google Chrome. This would allow Unity-authored content to be played in any browser that supports Native Client.

Linux

There have been several indications at this point that a Linux port is in the works. Specifically, an end-user discovered an option for Linux as a runtime platform in Unity itself and work on a Linux port was later confirmed by a Unity Technologies developer. A prototype of a web-plugin for Firefox on Linux was also blogged about on Unity's corporate blog and another Unity Technologies employee has publicly indicated that work has been done on a Linux port. However, Unity Technologies has not made any official public statement regarding status of the port or an estimated release date.

With the upcoming support for Flash, Linux users will be able to play Unity-authored content with a Flash browser plug-in.

Roku 2

On September 28 it was announced that Unity will provide content for the streaming box top set, Roku 2 through its Union initiative.

Shortfalls

DirectX 11

The Unity game engine does not currently offer any DirectX-11 support,. However, Unity employees have indicated that they are working on it.

PS Vita Support

Additionally, the game engine has not announced support for the soon to be released PlayStation Vita, while Unreal Engine 3 has announced the ability to export to the PlayStation Vita platform. Nevertheless, Square Enix has licensed the Unity Engine for a PS Vita and PS3 cross-platform project, but support for the PS Vita in this project might be done internally by Square Enix and not by Unity Technologies.

AI Tools

Unity has yet to release any form of an Artificial Intelligence tool or section of the editor, however in the latest Unite 11 Keynote, it was announced there will be a path finding and crowd simulation implementation in Unity's next version, 3.5. Many of the AI features Unity does not inherently include can be obtained via 3rd party plugins such as RAIN- AI Engine.

Dynamic Destruction

Also known as "destructible environments", Unity does not support any form of dynamic breaking apart of 3d objects. Although Unity supports most of the features of Nvidia PhysX, it does not allow APEX Destruction, a part of PhysX which allows the configuration of rules as to how 3d objects within the game-space will be broken apart based on user interaction.

Unity does, however, provide a code library that allows users to directly edit the shape of all game objects, allowing savvy users to create custom systems that can break apart objects. An example of one of these is the Piecemaker - Mesh Destruction Asset

See also

• List of game engines

External links

• Official website
• Unity's channel on YouTube
• Unity on Facebook
• Unity on Twitter
• Unity Forums (official Unity community)
• Unity Insider (German Unity magazine and community)
• Unity's channel on YouTube
• design3, Unity's Authorized Training Partner
• Unity 3D Games