If you have worked with any 3D application before, you'll likely be familiar with the concept of the z axis. The z axis, in addition to the existing x for horizontal and y for vertical axes, represents depth. In 3D applications, you'll see information on objects laid out in an x, y, z format—this is known as the Cartesian coordinate method. Dimensions, rotational values, and positions in the 3D world can all be described in this way. In this book, as in other documentation of 3D, you'll see such information written with parentheses, shown as follows: Cube at (3,5,3).
This is mostly for neatness, and also due to the fact that, in programming, these values must be written in this way. Regardless of their presentation, you can assume that any set of three values separated by commas will be in an x, y, z order.
This convention is derived from Maya, where the y axis is the up axis while z is the forward axis. Not all graphic packages and engines use this coordinate system. For example, in 3DS Max and Vicious Engine, y is the forward axis while z is the up axis.
In the following screenshot, a cube is shown at the location Cube at (3,5,3) in the 3D world, meaning it is 3 units from 0 in the x axis, 5 up in the y axis, and 3 forward in the z axis:
