id Tech
Engines that built genres
id Tech engines powered Doom, Quake, and countless licensed games, with source releases educating generations of programmers.
Overview
John Carmack’s engines at id Software defined technical standards for PC gaming. Each generation brought innovations that competitors studied and licensed. The Doom engine made first-person action viable. Quake engines brought true 3D and internet multiplayer. Source code releases created educational resources that trained countless developers.
Fast facts
- Developer: id Software (primarily John Carmack).
- First engine: id Tech 1 (Doom engine, 1993).
- Licensing: Major revenue source for id.
- Open source: Most versions eventually released.
Engine generations
| Version | Year | Notable game | Innovation |
|---|---|---|---|
| id Tech 1 | 1993 | Doom | Binary space partitioning |
| id Tech 2 | 1996 | Quake | True 3D, client-server |
| id Tech 3 | 1999 | Quake III Arena | Shader system |
| id Tech 4 | 2004 | Doom 3 | Unified lighting |
| id Tech 5 | 2011 | Rage | MegaTexture streaming |
| id Tech 6 | 2016 | Doom (2016) | Vulkan rendering |
| id Tech 7 | 2020 | Doom Eternal | Ray tracing support |
id Tech 1 (Doom engine)
1993 breakthrough:
- Binary space partitioning for rendering.
- Height variation (unlike Wolfenstein).
- Lighting effects.
- Networked multiplayer.
- Not true 3D (no room-over-room).
Licensed by: Heretic, Hexen, Strife.
id Tech 2 (Quake engine)
1996 true 3D:
- Real polygon-based 3D.
- Hardware acceleration support (GLQuake).
- Client-server networking.
- True room-over-room architecture.
- TCP/IP internet play.
Licensed by: Half-Life (heavily modified), SiN.
id Tech 3
1999 refinement:
- Curved surfaces (Bezier patches).
- Shader-based rendering.
- Skeletal animation.
- Widely licensed.
Licensed by: Call of Duty (early), Medal of Honor, Star Wars Jedi Knight II.
id Tech 4
2004 unified lighting:
- Real-time shadows everywhere.
- Normal mapping.
- Physics integration.
- Higher system requirements.
Licensed by: Prey, Quake Wars, Brink.
Source code releases
Educational impact:
- Doom source released 1997.
- Quake source released 1999.
- Each engine eventually open-sourced.
- Spawned source ports and studies.
- Trained generation of programmers.
Source ports
Community continuations:
- GZDoom: Modern Doom engine.
- DarkPlaces: Quake engine enhanced.
- ioquake3: id Tech 3 maintained.
- Active development decades later.
Technical innovations
Carmack’s contributions:
| Technique | Engine | Impact |
|---|---|---|
| BSP trees | Doom | Efficient rendering |
| Surface caching | Quake | Dynamic lighting |
| Stencil shadows | Doom 3 | Unified lighting |
| MegaTexture | id Tech 5 | Unique textures everywhere |
Licensing model
Business approach:
- License fees for commercial use.
- Technical support included.
- Eventually open-sourced older engines.
- Funded continued development.
Competition and influence
Unreal Engine rivalry:
- Both licensed widely.
- Different design philosophies.
- id more technically focused.
- Unreal more tool-focused.
- Both shaped industry standards.
Modern id Tech
Under ZeniMax/Microsoft:
- Vulkan-first rendering.
- 60+ FPS targets on console.
- Ray tracing integration.
- Powers Doom, Wolfenstein, other Bethesda titles.
Legacy
id Tech engines established technical benchmarks across three decades. Their source releases created educational resources unmatched in the industry. Every FPS engine traces lineage to Carmack’s work.