hm yes indeed at the moment the dash-dot pattern is crudely hard-coded to some value that worked for me... Indeed it's probable that it doens't work nicely for other people. I think the best course of action would be to add a preference setting so the user can customize the pattern... Can I ask you to make a feature request on http://www.freecadweb.org/tracker/
? Otherwise I will probably forget about this... Thanks!