Using this tag, one of the vertex cluster's axes can be bound to the world or Object Tracker coordinate system and - even more importantly - the scaling of the vertex cluster can be defined.

Use the tag as follows to calibrate (2 methods):

• Create the tag for the respective Motion Tracker or Object Tracker object. An axis with handles at each end will appear at the center of the Viewport. Drag these handles onto 2 Tracks or 2 features, respectively, that should be used to define the world or object axis:
  
  
  
  

As soon as the axis is defined in the tag's settings, the vertex cluster will be oriented accordingly. The value entered for Length (i.e., the actual real-world length, e.g., 100 cm for a table edge) will scale the points accordingly.

• Select the Create Vector Constraint tool (main menu Tracker | Constraints and click on the desired Track. A Vector Constraint tag with a linked Null object that matches the Track will be created automatically.

Create Vector Constraint

This command creates a Vector Constraint tag with a matching linked feature (see previous paragraph).