Access: Click
the Automatic Center icon 
on the Automation toolbar
or choose Automation / Automatic Center
from the main menu.
This tool enables you to automatically create a center line through circles, arcs or projected splines of an assembly view.
To create an automatic Center Line:
Click the Automatic
Center icon on the Automation
toolbar or choose Automation /
Automatic Center from the main menu. The Automatic
Center dialog is displayed:
Pick the required assembly view.
Set the Parameters and Filter properties. (Click the Automatic Center dialog for explanations).
Click OK
or Apply 
to create the center lines:
