2. Secondly, draw a straight line in the drawing area, and click the parameter menu in the menu bar.
3. Finally, select the geometric constraint, vertical, select the first object, one of which is a straight line, and then select another straight line as the second object. At this time, the relative relationship between the second object and the first object is vertical by rotation. At this time, we can drag any object, and the other object will rotate accordingly, making it always vertical.