When drawing in 2D, what axis do you NOT work with?
Z (3-D work has an added axis, the Z-axis.)
The AutoCAD software uses Cartesian (X,Y) coordinates to indicate locations in a drawing. Points are located by designating a horizontal (X) and vertical (Y) distance as measured from the origin (0,0) (as shown in Fig 1). There is also a third coordinate (Z), which is only used in 3D drawings.
Fig 1: Locating Points