Following an Axis or Cylinder
To create a pipeline segment by following an axis or a cylinder, click > 
Follow Axis. When you select a cylinder, the system creates an internal axis for the segment to follow.
Follow Axis. When you select a cylinder, the system creates an internal axis for the segment to follow.By default, the ends of the routed segment correspond to the endpoints of the axis it followed. However, you may extend the ends beyond the axis that it follows.