By default, X, Y, and (for 3-D data spaces) Z axes are displayed in the iTool window. 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 most data spaces to make it easier to identify characteristics.
To add an additional axis to your data space:
Use the mouse to position the new axis, and double-click the axis to display the axis property sheet.