Add CVs or edit points to the end of a curve
         
         
            - Select the curve to add CVs, or select the last edit point to add edit points.
- Select Edit Curves > Add Points Tool. 
            
- Click in the view to add new CVs or edit points.
- Press  to finish the curve. to finish the curve.
 Extend a curve or curve-on-surface a certain distance
         
         
            - Select the curve.
- Choose Edit Curves > Extend > Extend Curve >  or Edit Curves > Extend > Extend Curve on Surface > or Edit Curves > Extend > Extend Curve on Surface > . .
- Click  (or  for a curve-on-surface) and enter the distance you want to extend the curve. You can interactively change the distance in
               the channel box or attribute editor after you extend.
               For curves-on-surface the sets a fraction of the surface length in the direction the curve runs. For instance, a value of 0.5 extends the curve length
                  by roughly half the length of the surface in the direction the curve runs.
                
- Do one of the following:
                  - Click  to extend the curve in a straight line.
                  
- Click  to extend the curve in an arc.
                  
- Click  to maintain tangent continuity with the current shape of the curve.
                  
 
- Set  to choose which end (or  ends) to extend from.
            
- To make the extension part of the current curve, turn on . Turn this option off to make the extension a new curve.
            
- Click  or .
            
 Extend one end of a curve or curve-on-surface out to exact coordinates
         
         
            - Select the curve.
- Choose Edit Curves > Extend > Extend Curve >  or Edit Curves > Extend > Extend Curve on Surface > or Edit Curves > Extend > Extend Curve on Surface > . .
- Click  (or  for a curve-on-surface).
            
- Set  to choose which end to extend from.
            
- To make the extension part of the current curve, turn on . Turn this option off to make the extension a new curve.
            
- Click .
               Tip 
                     When  is on in the  option box, Maya will create an extend node on the curve. You can select the extend node in the channel box or attribute
                        editor to tweak the extend operation, including distance, interactively.