Sketcher > Modifying a Section > Modifying a Spline > To Add Points or Vertices
  
To Add Points or Vertices
1. Select the spline you want to modify.
2. Right-click in the Sketcher window and choose Modify from the shortcut menu. The Spline tab opens.
3. Right-click on a location on the spline. A shortcut menu appears.
4. Click Add Point.
 
* You can extend a spline by clicking on an endpoint.