Adding a Center Mark or Center Line
- 
                Click the Center Line tool 
.
             - Click an:
Edge of the end of the cylinder or hole to add a center mark.
Cylindrical face to add a center line.
Sphere to add a center mark.
 
.
            Edge of the end of the cylinder or hole to add a center mark.
Cylindrical face to add a center line.
Sphere to add a center mark.