Move the selected location without modifying the tangency conditions

To move a point of a curve without modifying the tengency conditions of the curve in that point, start the Curve Shape Constraint command and proceed as follows.

1	Select the curve by clicking on the location you want to edit. A handle will be displayed on the curve in the location you selected:
	You are now enabled to change the curve shape by moving the location you selected on it or by modifying the tangency conditions in the same location.
2	To move the selected location without modifying the tangency conditions, click on the selected location, which is the middle point of the handle and has a marker on it, and drag it to the new position. Click in the new position. You can also use the Step option under Tools to display the Modify Selected Points dialog box. Step This setting specifies the step by which the arrow buttons move the selected points in the corresponding direction: hence, each time you click one of the arrow buttons, the point moves in the direction of the arrow by a distance equal to the value of the step. Arrows Click one of the arrow buttons: the point moves in the direction of the arrow (+x, -x, +y, -y, +z, -z) by a distance equal to Step each time you click. You can constrain points to move along an axis. See Moving points along an axis