At first you need to make sure you're pentable is set and
active, otherwise pro/e will use software linefonts and
you won't be able to influence anything.
The pentable given by dr_gallup is a nice example.
The color names behind the pens are optional and force a
certain line color to a pen. When not stated Pro/e uses
an internal list to map the lines to the pens.
It is advised to state half_tone_color behind pen
3 because this prevents the line scale of the dotted
lines to change along with the paper size.
For more info about line colors see the downloadable
color reference chart in this thread:
http://www.mcadcentral.com/proe/forum/forum_posts.asp?
TID=44465
Edited by: Joost_t