# IW (game engine)

The IW engine is a game engine created and developed by Infinity Ward, with the current iteration developed in its studio in Kraków, Poland for the Call of Duty series. The engine was originally based on id Tech 3 by id Software with Ritual Entertainment's ÜberTools enhancements. Aside from Infinity Ward, the engine is also used by other Activision studios working on the series, including primary lead developers Treyarch and Sledgehammer Games, and support studios like Beenox, High Moon Studios, and Raven Software.

## History
### IW 2.0 to IW 3.0

The engine has been distinct from the id Tech 3 engine on which it is based since Call of Duty 2 in 2005. The engine's name was not publicized until IGN was told at the E3 2009 by the studio that Call of Duty: Modern Warfare 2 (2009) would run on the "IW 4.0 engine". Development of the engine and the Call of Duty games has resulted in the inclusion of advanced graphical features while maintaining an average of 60 frames per second on the consoles and PC.
Call of Duty 4: Modern Warfare was released using version 3.0 of the engine. This game included features such as bullet penetration, improved AI, lighting engine upgrades, better explosions, particle system enhancements and many more improvements. Treyarch began using an enhanced version of the IW 3.0 engine for Call of Duty: World at War. Improvements were made to the physics model and dismemberment was added. Environments also featured more destructibility and could be set alight using a flamethrower. The flamethrower featured propagating fire and it was able to burn skin and clothes realistically. Treyarch modified the engine for their James Bond title, 007: Quantum of Solace.

### IW 4.0 to IW 5.0

Call of Duty: Modern Warfare 2 (2009) was released using the IW 4.0 engine, the only game to do so. The IW 4.0 engine featured texture streaming technology to create much higher environmental detail without sacrificing performance. Call of Duty: Black Ops was not based on IW 4.0; rather, Treyarch further enhanced the version of IW 3.0 they had used in their previous game. This version of the engine also featured streaming technology, lighting enhancements, and support for 3D imaging. Call of Duty: Modern Warfare 3 (2011) utilizes an improved version of the IW 4.0 engine. Improvements on the engine allowed better streaming technology which allowed larger regions for the game while running at a minimum of 60 frames per second. Further improvements to the audio and lighting engines were made in this version.
Call of Duty: Black Ops II was developed using a further iteration of the IW engine. Texture blending was improved due to a new technology called "reveal mapping" which compared tones between two textures and then blends them together. Also, there were upgrades to the lighting engine which included HDR lighting, bounce lighting, self-shadowing, intersecting shadows and various other improvements. Call of Duty: Black Ops II took advantage of DirectX 11 video cards on the Windows version of the game. The "zombie" mode was moved to the multiplayer portion of the engine which will allow for much more variety within this part of the game.

### IW 6.0 to IW 7.0

Call of Duty: Ghosts features an upgraded version of the IW 5.0 seen in Call of Duty: Modern Warfare 3 (2011). It was unknown whether or not any engine features have been taken from Call of Duty: Black Ops II. Since the main developer was Infinity Ward they returned to their original engine naming system and called that iteration IW 6.0. IW 6.0 was compatible with systems such as Xbox One and PlayStation 4 so polygon counts, texture detail and overall graphical fidelity had increased. IW 6.0 was also compatible with Microsoft Windows, Wii U, PS3 and Xbox 360. The IW 6.0 engine featured technology from Pixar, SubD, which increased the level of detail of models as one got closer to them. Mark Rubin said about the HDR lighting "We used to paint it in and cover up the cracks, but now it's all real-time". Ghosts used Iris Adjust tech which allowed the player to experience from a person's point of view how their eyes would react to changes in lighting conditions realistically. Other features included new animation systems, fluid dynamics, interactive smoke, displacement mapping and dynamic multiplayer maps.
Call of Duty: Black Ops III used a highly upgraded version of the engine used in Black Ops II for the PS4/Xbox One/PC/macOS version. Call of Duty: Infinite Warfare's IW 7.0 featured weightlessness system, game physics improvement, improved AI and improved non-player characters behaviors. For Call of Duty: Black Ops 4, Treyarch heavily modified the engine used in Black Ops III to support up to 100 players, and introduced a new 'Super Terrain' system.

### IW 8.0 to IW 9.0

With Call of Duty: Modern Warfare (2019) and Call of Duty: Warzone, Infinity Ward employed their Poland studio to rebuild the engine completely. Dubbed IW 8.0, the engine was created within five years, and featured substantial upgrades such as spectral rendering, volumetric lighting and support for hardware-accelerated ray tracing on the PC version. Support for Nvidia's Deep Learning Super Sampling (DLSS) was added later in April 2021. Activision stated that the new engine was also shared across the board for all Call of Duty developers to use in future titles. Call of Duty: Black Ops Cold War is an exemption (comparing to Black Ops 6), utilizing a highly modified version of the Black Ops III and 4 engine. Call of Duty: Vanguard was powered by the same engine used in Modern Warfare and Warzone with enhancements from developer Sledgehammer Games.
Call of Duty: Modern Warfare II (2022) was developed on a highly upgraded version of the engine first used in 2019's Modern Warfare. Dubbed IW 9.0, the engine was co-developed by Infinity Ward, Treyarch, and Sledgehammer Games, and was planned to be used in future installments of the series in a unified effort to ensure that every studio was working with the same tools, allowing them to create a single cross-game launcher, known as Call of Duty HQ, which was later known as the Call of Duty launcher. Call of Duty: Modern Warfare III (2023) was also planned to use this engine and be integrated into the Call of Duty HQ launcher, which was later known as the Call of Duty launcher. Call of Duty: Black Ops 6 introduces a new movement system called Omnimovement which lets players sprint, dive, and slide in any direction, combined with the ability to rotate 360 degrees while prone.

### Sledgehammer Games engine

Call of Duty: Advanced Warfare featured Sledgehammer Games' heavily modified in-house branch of the IW engine, with only a few lines of legacy code remaining. The majority of the engine in Advanced Warfare had been rewritten. Sledgehammer Games incorporated brand new animation, physics, rendering, lighting, motion capture and facial animation systems. The developers reworked the audio engine which had also been built from the ground up. According to Sledgehammer Games audio director Don Veca, the team was able to integrate an audio intelligence system to the game.
Call of Duty: Modern Warfare 2 Campaign Remastered was confirmed to have been developed on an advanced version of this engine with modifications from Beenox. Beenox introduced enhancements to the original game including new models and animations as well as rebuilt textures. Call of Duty: WWII uses an improved version of Sledgehammer Games' in-house engine from Advanced Warfare. Sledgehammer Games eventually replaced this engine with IW 8.0 for their next game, Call of Duty: Vanguard, in 2021.

## Games using IW engine

| Title | Version | Year | Notes | Features |
| Call of Duty 2 | IW 2.0 | 2005 | Modified version of id Tech 3 from Call of Duty (Call of Duty: Classic on PS3/Xbox 360) | Normal mapping Light bloom Heat haze Enhanced textures Unified shadowing system Game console support DirectX 9 support |
| Call of Duty 4: Modern Warfare Call of Duty: Modern Warfare – Reflex Edition | IW 3.0 | 2007 2009 | Highly upgraded version of Call of Duty 2's IW 2.0 engine | Support for Wii Dynamic physics engine Bullet penetration Improved AI Lighting engine upgrades Upgraded animation systems Improved shadows Particle system enhancements Ragdoll physics integrated into character death animations Self-shadow every frame Audio system enhancements Motion control aiming support |
| Call of Duty: World at War | IW 3.0 | 2008 | Call of Duty 4: Modern Warfare's IW 3.0 engine updated | Audio occlusion Improved physics Ragdoll physics after death animations Dismemberment More destructible environments Realistic burning of skin and clothing Propagating fire |
| 007: Quantum of Solace | IW 3.0 | 2008 | Modified version of Call of Duty 4: Modern Warfare's IW 3.0 engine | Cover system |
| Call of Duty: Modern Warfare 2 Call of Duty Online | IW 4.0 | 2009; 2015 | Upgraded from Call of Duty 4: Modern Warfare's IW 3.0 engine | Texture streaming technology Lighting improvements Improved AI Improved physics More efficient rendering |
| Call of Duty: Black Ops | IW 3.0 | 2010 | Call of Duty: World at War's IW 3.0 engine updated | Texture streaming technology Stereoscopic 3D support Deferred lighting |
| Call of Duty: Modern Warfare 3 | IW 5.0 (MW3 engine) | 2011 | Improved version of Call of Duty: Modern Warfare 2's IW 4.0 engine | Improvements to texture streaming technology to allow for larger regions Lighting engine enhancements to show reflections of some objects on tile floors Improvements to the audio engine |
| Call of Duty: Black Ops II | Black Ops II engine (Updated version of IW 3.0) | 2012 | Call of Duty: Black Ops' IW 3.0 engine heavily modified | Support for Wii U Reveal mapping (improved texture blending) Improved water effects Improved lighting effects Lens flare effects HDR lighting Bounce lighting Self-shadowing Intersecting shadows DirectX 11 for Windows version Improvements to the audio engine |
| Call of Duty: Ghosts | IW 6.0 | 2013 | Significantly upgraded version of Call of Duty: Modern Warfare 3's engine (IW 5.0) | Pixar's SubD (models sub-divide the closer the player gets to them) New animation systems for movement (sliding, leaning etc.) Fluid dynamics Interactive smoke Improved AI Dynamic multiplayer maps Displacement mapping New volumetric HDR lighting system Iris Adjust tech Support for eighth generation consoles (PlayStation 4 and Xbox One) Graphics Tessellation for Windows, PlayStation 4 and Xbox One PhysX support for Windows version Specular mapping on particle effects Use of Umbra's advanced rendering technology (Umbra 3) |
| Call of Duty: Advanced Warfare | Sledgehammer Games engine | 2014 | Heavily modified and overhauled from Call of Duty: Modern Warfare 3's IW 5.0 engine | Built from the ground-up for PlayStation 4 and Xbox One New renderer with physically-based rendering New animation systems New physics systems New audio systems New motion-capture and facial animation systems Filmic post-effects pipeline Materials-based lighting |
| Call of Duty: Black Ops III (PS4/Xbox One/PC/macOS version) | Black Ops III engine (derived from IW 3.0) | 2015 | Call of Duty: Black Ops II's updated IW 3.0 engine heavily modified | New renderer New animation systems Improved lighting Dynamic water simulation system Dynamic Movement Dynamic resolution scaling Upgraded physics systems Upgraded AI |
| Call of Duty: Infinite Warfare | IW 7.0 | 2016 | Significantly upgraded from Call of Duty: Ghosts' heavily modified engine (IW 6.0) and incorporating aspects of the engine overhaul for 2019's Call of Duty: Modern Warfare | Physically-based rendering Re-written lighting systems Zero-gravity simulation system Re-written animation systems Physics improvements Re-written AI Improved NPC behaviors Streaming level transition improvement New performance capture stage Dynamic Movement Advanced photogrammetry |
| Call of Duty: Modern Warfare Remastered | Modified IW (derived from Sledgehammer Games engine) | 2016 | Upgraded version of Call of Duty: Advanced Warfare's engine with modifications from Raven Software | Updated models New animations Rebuilt textures Upgraded lighting system |
| Call of Duty: WWII | Sledgehammer Games engine | 2017 | Improved version of Call of Duty: Advanced Warfare's engine | Advanced photogrammetry HDR and improved lighting Materials-based lighting Upgraded post-effects pipeline |
| Call of Duty: Black Ops 4 | Black Ops 4 engine (derived from IW 3.0) | 2018 | Updated from Call of Duty: Black Ops III's engine | Improved lighting Enhanced dynamic water simulation Slimmed Dynamic Movement New 'Super Terrain' system |
| Call of Duty: Modern Warfare Call of Duty: Warzone | IW 8.0 (Rebuilt engine) | 2019; 2020 | Heavily rebuilt and overhauled version of IW engine with much improved lighting, rendering, physics, textures, audio, etc. | New lighting engine with across the board volumetrics Improved physics Improved animations New sound engine New texture streaming technology Ray tracing support for PC via NVIDIA RTX graphics cards New physically-based rendering engine Spectral rendering Advanced photogrammetry Tesselation upgrades with new geometry culling algorithm DirectX 12 API Dolby Atmos support Large map streaming DLSS support added on April 22, 2021 Improved post-process pipeline Cross-platform play and cross-platform progression support |
| Call of Duty: Modern Warfare 2 Campaign Remastered | Modified IW (derived from Sledgehammer Games engine) | 2020 | Upgraded version of Call of Duty: Modern Warfare Remastered's engine with modifications from Beenox | Updated models New animations Rebuilt textures Upgraded lighting system Improved shader effects Revamped post-process pipeline |
| Call of Duty: Black Ops Cold War | Black Ops Cold War engine | 2020 | Upgraded version of Call of Duty: Black Ops 4's engine (heavily modified IW 3.0) | Support for ninth generation consoles (PlayStation 5 and Xbox Series X/S) Improved real-time lighting Hardware-based ray tracing support for next-gen consoles PC ray tracing and DLSS support via NVIDIA RTX graphics cards FoV Slider for Xbox One, PS4, Xbox Series X, PS5, PC |
| Call of Duty: Vanguard | IW 8.0 | 2021 | Upgraded version of Call of Duty: Modern Warfare's engine | Photorealistic graphical details Textures with a damage layer system Tactical destruction Advanced variable rate shading (VRS) system AMD FidelityFX Super Resolution support |
| Call of Duty: Modern Warfare II Call of Duty: Warzone 2.0 Call of Duty: Modern Warfare III Call of Duty: Warzone Mobile | IW 9.0 | 2022; 2023 | Highly upgraded version of Call of Duty: Modern Warfare's engine | Support for mobile devices (Android and iOS) New water simulation system Improved AI New audio engines Improved 3D directionality and immersive audio Cross-game support within a single launcher on consoles and PC (Call of Duty HQ, later known as the Call of Duty launcher) Updated rendering with variable rate shading Gyro aiming support |
| Call of Duty: Black Ops 6 | Upgraded IW 9.0 | 2024 | Upgraded version of Call of Duty: Modern Warfare II & III's engine | New movement system (Omnimovement) Intelligent movement HUD presets and customization Improved audio Auto-mantling |