In Locked Plane mode, the digitizer tip passes through a pre-defined planes to digitize points. Define multiple Lock Planes and set the digitizing mode to Stream/Undo mode to space the planes at equal distances. Define points as the digitizer tip passes through each Lock Plane.
To define Lock Planes click Options > Locked Plane Settings.

Locking Plane
Choose the plane to intercept digitizer input when in Locked Plane digitizing mode
XY, YZ, or ZX Plane
Choose the plane.
Define Plane
Click this button to define a plane by its normal vector and distance from origin. Digitize three points that define the plane, and the system calculates the IJK normals and distance from origin (or world zero).
Plane Definition Options
Distance from plane to origin
Define the location of the first Locking Plane.
Distance between planes
Define the incremental distance between multiple Locking Planes.
Number of planes
Define the number of Locking Planes to set.
Define location of the initial plane
Digitize and let the system calculate the "Distance from plane to origin" value automatically.