About Pens
There are two types of pen: cosmetic and geometric. A cosmetic pen is used with applications requiring lines of fixed width and lines that are quickly drawn. A CAD application, for example, uses a cosmetic pen to generate hidden, section, center, and dimension lines that are between .015 and .022 inches wide regardless of the scale factor. A geometric pen is used with applications requiring scalable lines, lines with unique end or join styles, and lines that are wider than a single pixel. A spreadsheet application, for example, uses a geometric pen to define each of the bars in a bar graph as a wide line.