Commercially, id Tech 3 competed with early versions of the Unreal Engine; both were widely licensed.

Unlike most other game engines released at the time—including its primary competitor, the Unreal Engine—id Tech 3 requires an OpenGL-compliant graphics accelerator to run.

[3] In order to assist calculation of these shaders, id Tech 3 implements a specific fast inverse square root function, which attracted a significant amount of attention in the game development community for its clever use of integer operations.

id Tech 3 uses a snapshot system to relay information about game frames to the client over UDP.

[citation needed] Developers must manually deactivate pure server to test maps or mods that are not in data packs using the PK3 file format.

[11][12][13][14] The project added features including builtin VoIP support, Anaglyph stereo rendering (for viewing with 3D glasses), and numerous security fixes.

Ioquake3 is the basis of several game projects based on the id Tech 3 engine, such as OpenArena (mimicking Quake III Arena), Tremulous,[15][16] Smokin' Guns,[17] Urban Terror,[18][19] Turtle Arena and World of Padman[20][21] and game engine projects such as efport (a Star Trek: Voyager – Elite Force Holomatch clone), ioJedi Outcast, ioJedi Academy, ioDoom3, and OpenMoHAA.

The cMod engine derived from the earlier Elite Force port was used to package the 20th anniversary freeware release of the game for Windows and Linux.