2D Tracking - Nuke 101: Professional Compositing and Visual Effects - page 203

By2Dtracking,Irefertothekindofdatayoucanextractfromtheimage.Becauseyouare
following a 2D image, an image projected on the flat screen, you can really only follow
the position of pixels as they move around it. The screen and the image have no depth—-
remember, they are flat. This situation results in nothing but 2D data and 2D transforma-
tions, much like the kind of transformation you can create using the Transform node. So
you can move in X and Y, but Z doesn't exist. You can scale up and down, and you can
rotate around the screen—but not into the screen. These are 2D transformations.
3D tracking, also called camera tracking, is the process of extracting the camera inform-
ation from the image, resulting in 3D transformations. Although 3D tracking uses some
of the same initial concepts of 2D tracking, 3D tracking is used in a very different way.
( Chapter 10 covers 3D tracking.)