Preliminary information given by John Carmack about this engine, which is still in early phases of development, tend to show that id Software is looking toward a direction where ray tracing and classic raster graphics would be mixed. However, he also explained during QuakeCon 08, the hardware that is capable of id Tech 6 did not yet exist.
In July 2011, he explained that id Software is beginning research for the development of id Tech 6.
It is unclear how Carmack's resignation from id will affect development of the id Tech engine henceforth.
It would work by raycasting the geometry represented by voxels (instead of triangles) stored in an octree.John Carmack claims that this format will also be a more efficient way to store the 2D data as well as the 3D geometry data, because of not having packing and bordering issues. It will virtualize geometry like textures.
^ abc"John Carmack on id Tech 6, Ray Tracing, Consoles, Physics and more". PC Perspective. 2008-03-12. What John does see ray tracing useful for is a very specific data model he has created called "sparse voxel octrees" that allow him to store immense amounts of data in a fashion that is easily accessed using ray tracing methods(...) This new data model and algorithm being worked on for id Tech 6 would allow, according to John, nearly infinite amounts of geometric detail in the world without the problems seen with tessellation engines or trying to store gigabytes of data locally