The reference coordinate system determines the orientation of the X, Y, and Z axes used by the transform. The type of transform system you use affects all transform operations.
You specify the transform coordinate system using the Reference Coordinate System list.
While modeling, it’s often helpful to have a temporary, movable local axis so you can rotate or scale about an arbitrary center.
To create an adjustable local axis:
The name of the point object appears in the list as the active coordinate system.
Now you can use the point object’s coordinate system as an adjustable axis.