To Add an Endpoint
1. Select the spline and click 
, or double-click the spline in the Sketcher window. The Spline tab opens.
, or double-click the spline in the Sketcher window. The Spline tab opens.2. Press and hold CTRL + ALT, and then click a location in the graphics window. An end point is added after the nearest endpoint.
3. Continue to click in the graphics window to add additional points, middle-click to exit the tool.