By default, volumes are displayed with X, Y, and Z axes. The display of these axes is controlled by property sheets for the axes container and for individual axes (see Axes). Additional X, Y, or Z axes can be added to a volume visualization to make it easier to identify volume characteristics.
To add an axis to your volume visualization:
Use the mouse to position the new axis and double-click the axis to display the axis property sheet.
For more information on adding axes, see Additional Axes, "Adding Annotations".