Cardinal Points
Cardinal Points can be turned on for any geometry. These points can be used as the input for other GR-Relationships to build dynamic ge- ometry. For example, if you wish to build a line along the axis of a cylinder you can turn on the cardinal points for the cylinder and use those points to build line. As the cylinder updates the cardinal points will update and so will the position and length of the line.
Different numbers of cardinal points exist for different geometry types and the choice to turn on and off particular points and to control their naming is given when you turn them on.