Sketcher > Creating Sketcher Geometry > Points, Centerlines, and Coordinate Systems > Construction Points, Centerlines, and Coordinate Systems > To Create a Construction Centerline
  
To Create a Construction Centerline
1. In the Sketching group, click Centerline.
2. Select a point for the first point. A centerline that rubberbands to the pointer is created.
3. Select another point on the centerline. The centerline is placed.