Belated documentation of slightly modified, long-established AC10 project folder setup.
Summary: With the model and the layouts in one file, pen sets manage the difference between the model pens and the output pens. In addition, they can do view-option-type tricks.
Background: In Archicad 9, there was one set of pens. In PlotMaker 9, there was also only one, and it could be different from the set in AC. Or, each drawing could have its own pens, but it was impractical.
Our standard has always been to use a colorful set of pens for modeling, which translates into a black/white/gray set of pens in layouts. We are far from unique in this arrangement.
In 10, they threw PM into the abyss, so they needed a method to maintain at least those two groups of pens within the new unified project file. So, Pen Sets.