Drawing constraints provide the capability to constrain one of the axes when you are drawing or reshaping lines and poly shapes. Using the drawing constraints you can quickly draw a line or edge of a poly shape parallel to the Section Designer X or Y axes or at any arbitrary angle. The drawing constraint tools can be activated using the Draw menu > Constrain Drawn Line to command or they can be activated by pressing either the X, Y or A key on your keyboard.
The drawing constraints include:
Constant X: Locks the X component of the next point so that it is the same as the previous point.
Constant Y: Locks the Y component of the next point so that it is the same as the previous point.
Constant Angle: Allows you to specify an angle in degrees in the status bar at the bottom of the Section Designer window. Drawing is then constrained along this angle. The angles are measured from the Section Designer X-axis. Positive angles appear counterclockwise as you look down on the section. Note that when you use the keyboard command to specify a constant angle constraint, every time you press the A key on the keyboard the constant angle changes to be equal to the angle of the line that is within the screen selection tolerance (Options menu > Preferences > Dimensions/Tolerances command) distance from the mouse pointer. You can, of course, always change this angle by editing it in the Section Designer status bar.
None: Removes the current drawing constraint. Pressing the space bar on your keyboard also removes the current drawing constraint.
There are three steps to using the constraint tools:
Locate the first point.
Press one of the constraint keys on the keyboard (X, Y or A) or use the Draw menu > Constrain Drawn Line to command.
Locate the next point. Section Designer only picks up the unconstrained component of the next point.
Drawing constraints are always removed as soon as you draw the next point.
Note that snaps can be used in conjunction with constraints. In this case only the unconstrained component of the selected snap point is used when a constraint is selected.