The partially dotted line tool allows you to draw lines which have one section partially dotted. This is particularly useful when your diagram is representing something in 2D.
Constructing one of these lines is the same as constructing any line given the two end points. The difference can be seen when you select the line.
The two amber control points allow you to control which section of the line is dotted. If you move one of these to the end of the line, you can construct a line that is "half and half".
If you change the line style to none, you can create a line with a blank section.
