The latest in the id Tech engine to be developed at id Software by John Carmack, designed to be used to power Rage and Doom 4; It will be based on OpenGL and DirectX 9 technology, eliminating the need for DirectX 10 and Windows Vista. The PC version of the engine will come with a content-creation tools package called id Studio and unlike the engine, id Studio will only work on a Windows Operating System.
The lead programmer of the engine, John Carmack, has stated that id Tech 5 will use as much proprietary technology as possible to avoid licensing issues when the engine will eventually be released as open source some time in the future.
The id Tech 5 engine uses a more advanced form of the MegaTexture technology seen in Enemy Territory: Quake Wars. Where Quake Wars could only use a single static MegaTexture for the terrain, id Tech 5 enables multiple MegaTextures that can also be mapped to in-game models, assets, sprites etc. These MegaTextures can be up to 128000x128000 pixel resolution which are streamed from removable media such as a hard drive, avoiding heavy RAM usage that occurs when using standard, multiple repeating textures. Because of the minor impact on RAM and performance with MegaTextures, it allows the artists to add as much detail to the single MegaTexture as they want which means large amounts of detail and variation in the terrain, models, assets etc.
When rendering the Megatexture whilst playing, the required parts of the texture are streamed to the world as needed. Depending on where in the game world you are, the correct mipmap levels are applied to the environment around you.
The drawback with having such a high resolution texture is that one single uncompressed megatexture takes up 120GB of Hard Drive capacity, and getting that larger file size to the players hard drive is a difficult task. Because of this, John Carmack has said that the 'sweet spot' for the megatexture would be around 50GB after compression. Which means once the game is complete, id will go through the world and delete parts of the megatexture which occupy unseen space. For example, the back of mountains or the back of certain buildings which the player will never see throughout the game. The reason for 50GB being the 'sweet spot' is due to one Blu-Ray disc's capacity being 50GB meaning they could fit the game on one disc for the PS3. For the Xbox 360 a standard DVD only has 8.5GB of space, but id have said that the game will be coming out on four discs that will need to be installed to the hard drive in order to fit the 50GB megatexture. Which is how they get around the small capacity of the DVD's that the Xbox 360 uses. The PC will also utilize a similar installation method as the Xbox 360.
Licencing Out to Other Development Studios
Steve Nix has commented in response to how scalable id Tech 5 is for other genres: "Not only do we think people can make games outside the action-shooter space with our technology, we encourage it. We'd actually like to see those games made."
With id Software being owned by ZeniMax Media, and ZeniMax Media also owning Bethesda Softworks. There is some speculation that Bethesda will utilise the id Tech 5 engine for their games including the next game in the Elder Scrolls series. The problem is that id Tech 5 is not able to render Global Dynamic Lighting, meaning that a progressive day and night cycle is not possible. Therefore games like the Elder Scrolls series or any other games that want to utilize id Tech 5's ease of rendering a large open world which typically would include a day and night cycle, makes this engine unsuitable for those requirements in its current form.