id Tech is a family of game engines developed by id Software. The original id Tech engines lacked official numbering and were referred to as the Doom and Quake engines. id Tech 1 was used for both Doom and Quake and introduced true 3D rendering. Subsequent id Tech engines featured additional enhancements and were used in many popular games over the years, with id Tech 5 currently powering Rage and the upcoming Doom 4. id Software is also developing id Tech 6 to succeed id Tech 5.

2. id Tech
0 id Tech is the family of game engines designed and
developed by id Software.
0 Prior to the presentation of the id Tech 5-based game
Rage, the engines lacked official designation and as
such were simply referred to as the Doom and Quake
engines, from the name of the main game series the
engines have been developed for.
0 id Tech numbers 1, 2, 3, and 4 have been released as
free software under the GNU General Public License.

3. id Tech 0
0 id Software had developed 3D engines for several games
before creating id Tech 1. Each game's engine had
progressively more advanced 3D technology.
0 Hovertank 3D (1991) used solid-color drawn walls and
scalable sprites.
0 Catacomb 3-D (1991) added texture mapping to the walls.
0 Wolfenstein 3D (1992) increased the color palette from 16-
color EGA to 256-color VGA. The game engine was also
licensed out to other companies.
0 Shadowcaster (1993) features diminished lighting, texture
mapped floors and ceilings, walls with variable heights and
sloped floors.

4. Doom engine (id Tech 1)
0 Originally developed on NeXT computers, later ported
to MS-DOS for Doom’s initial release
0 Commercial games using Doom engine
0 Doom – id Software
0 Doom II: Hell on Earth – id Software
0 Heretic – Raven Software
0 Hexen: Beyond Heretic – Raven Software
0 Strife – Rogue Entertainment

6. Quake Engine (id Tech 1)
0 Less commonly, but also known as id Tech 1, the Quake
engine is the game engine that was written to power
1996's Quake. It featured true 3D real-time rendering and
is the first id engine to use the client–server model.
0 Commercial games using Quake engine
0 Quake (1996) – id Software
0 HeXen II (1997) – Raven Software
0 Half-Life (1998) - Valve Corporation (Half-Life uses the
GoldSrc engine, which is based on the engines for Quake and
Quake II)

8. id Tech 2
0 Previously known as the "Quake II engine". id Tech 2 is
based on the Quake engine, and features some
enhancements such as colored lighting and a new model
format. Game code is now written in C and loaded from a
DLL, in place of the original Quake engine's "QuakeC"
scripting language.
0 Commercial games using id Tech 2
0 Quake II – id Software
0 Heretic II – Raven Software
0 SiN – Ritual Entertainment
0 Soldier of Fortune – Raven Software

10. id Tech 3
0 Previously known as the "Quake III Engine", it was derived from id
Tech 2, although a large portion of code is new or re-written.
0 Commercial games using id Tech 3
0 Quake III Arena (1999) – id Software
0 Return to Castle Wolfenstein (2001) – Gray Matter Interactive (SP) /
Nerve Software (MP)
0 Wolfenstein: Enemy Territory (2003) – Splash Damage
0 Star Wars Jedi Knight: Jedi Academy (2003) – Raven Software
0 Call of Duty (2003) – Infinity Ward
i = 0x5f3759df - ( i >> 1 ); // what the fuck?

12. id Tech 4
0 Formerly the "Doom 3 engine", originally based on id Tech 3. It
has a C++ based engine framework, and a new renderer, AI
framework, physics engine, gameplay trigger system, and sound
framework.
0 Games using id Tech 4
0 Doom 3 (2004) – id Software
0 Quake 4 (2005) – Raven Software
0 Prey (2006) – Human Head Studios
0 Enemy Territory: Quake Wars (2007) – Splash Damage
0 Wolfenstein (2009) – Raven Software
0 Brink (2011) – Splash Damage
0 Prey 2 (2012) – Human Head Studios

14. id Tech 5
0 This is the engine being used for id Software's new games.
0 The engine is not based on any previous id Tech engines,
however it reuses much of the technology from the most
updated id Tech 4 engine, including MegaTexture
technology, parallax mapping, bloom, motion blur, soft
particles, soft shadows and pixel shader effects.
0 Games using id Tech 5
0 Rage (2011) – id Software
0 Doom 4 – id Software

16. id Tech 6
0 id Tech 6 is an upcoming OpenGL-based game engine
under preliminary development by id Software, which
will tentatively follow id Tech 5 for id Software games
following Rage and Doom 4. It will work by raycasting
the geometry represented by voxels (instead of
triangles) stored in an octree.

17. Questions?