About Editing Curve Tangents
You can select and drag tangents in the graphics window to modify them.
Change the length and direction of a tangent that is not constrained by dragging the vector. Constraints such as Align or Angle allow you to modify only the length.
Change only the length of a follower tangent. In the case of a connected curve, the tangent handle has two parts: a regular tangent vector on the leader and an arrow tangent vector on the follower. You can drag the follower tangent to change length only, as the direction is constrained by the leader. You can apply any of the other constraints except Tangent, Curvature, or Acceleration to the leader tangent. Changing the type of the follower tangent to any type except Tangent, Curvature, or Acceleration breaks the connection with the leader curve.
Align the tangent of a curve to another unconnected curve.
Use the following selections and keystrokes to make other changes to the tangent:
Action
Result
Select the leader tangent
Reverse the direction of the leader and the follower and the underlying soft point
Select the follower tangent or the arrow
Change the continuity level from tangent to curvature or vice versa
Hold down the SHIFT key while selecting the follower tangent or the arrow
Remove the connection between the leader and the follower curves
Hold down the CTRL + ALT keys while dragging the tangent.
Modify tangent length
Hold down the ALT key while dragging the tangent.
Modify tangent angle and elevation