The first thing you will need to do is measure the features used to create the 3-2-1 alignment. A 3-2-1 alignment uses three standard feature types for its creation. The numbers 3, 2, and 1 refer to the minimum number of hits you need to take on in order to measure these features.
Measure a Plane. The first feature is the leveling feature and should be a plane composed of three hits. PC-DMIS will level the part to this feature. This defines the origin and direction of the first axis (usually the Z axis).
Measure a Line. The second feature is the rotation feature and should be a line composed of two hits. PC-DMIS will rotate the part to this feature, orienting the second axis. The second hit of this feature should be in the positive direction of the axis, relative to your first hit. This feature defines the direction of the second axis (usually the X axis) and the origin of the third axis (usually the Y axis).
Measure a Point. The third and final feature is the origin feature composed of just one hit. Since PC-DMIS creates the origin for this axis from your first two features, the third point merely establishes the origin of the entire alignment. PC-DMIS will translate the part to this feature, making it the X=0, Y=0, and Z=0 location.
Once you've measured the necessary features, you're ready to create your alignment.