Almost any rigid object with at least 3 non colinear markers attached rigidly to the object can be used as a digitizing pointer.

in this example the CalTester rod is defined as a digitizing pointer.

Given an MTD2 Rod with the following dimensions (as defined for the CalTester)

with the following marker assignment.

The following digitizing wand configuration will compute a landmark at the TIP.

An image of the CalTester rod as a digitizing pointer.

Note the blue sphere displaying the location of the landmark located at the tip of the rod.<br.