To Place a Start Point for Closed Loops in Trajectory Milling
Perform one of the following steps to open the Start Point dialog box:
• Click the Start Point option in the Curve Cut dialog box for 3- and 5-axis trajectory milling sequences.
• Click the Start Point option on the References tab for 2-axis trajectory milling sequences.
You can change the value of the start point using the following options in the Start Point dialog box:
• Reference—Displays the reference vertex or start point of the chain. To change the reference vertex, click in the Reference collector and select another vertex. This moves the chain reference and start point location to the new reference location. Click 
to change the direction of the reference curve.
to change the direction of the reference curve.• Real—Set the start point at a distance from the reference.
• Ratio—Set the start point at a relative distance from the reference.
Alternatively, you can toggle between Real and Ratio options in the graphics window. Right-click the start point dragger and select Real or Ratio from the shortcut menu.
You can also edit the value of the start point by double-clicking the currently displayed value in the graphics window.