Arena Test on April 24, 1999, initially only for Mac OS before expanding to Windows at a later date. The Q3Test started with version 1.05 and included three levels that would be included in the final release: dm7, dm17, and q3tourney2. Id Software continued to update Q3Test up until version 1.09. id co-founder and former technical director John Carmack has stated that Quake III Arena is his favorite game he has worked on.Quake III Arena was shipped to retailers on December 2, 1999; the official street date for the game was December 5, although id Software chief executive officer Todd Hollenshead expected the game to be available as early as December 3 from retailers like Babbage's and EB Games. The game supported the A3D 2.0 HRTF technology by Aureal Semiconductor out of the box. Game engine The id Tech 3 engine is the name given to the engine that was developed for Quake III Arena. Unlike most other games released at the time, Quake III Arena requires an OpenGL-compliant graphics accelerator to run. The game does not include a software or Direct3D renderer. The graphic technology of the game is based tightly around a "shader" system where the appearance of many surfaces can be defined in text files referred to as "shader scripts". Quake 3 also introduced spline-based curved surfaces in addition to planar volumes, which are responsible for many of the surfaces present within the game. Quake 3 also provided support for models animated using vertex animation with attachment tags (known as the .md3 format), allowing models to maintain separate torso and leg animations and hold weapons. Quake 3 is one of the first games where the third-person model is able to look up and down and around as the head, torso and legs are separate. Other visual features include volumetric fog, mirrors, portals, decals, and wave-form vertex distortion. For networking, id Tech 3 uses a "snapshot" system to relay information about game "frames" to the client over UDP. The server attempts to omit as much information as possible about each frame, relaying only differences from the last frame the client confirmed as received (Delta encoding). id Tech 3 uses a virtual machine to control object behavior on the server, effects and prediction on the client and the user interface. This presents many advantages as mod authors do not need to worry about crashing the entire game with bad