Line width in Postscript Units can be specified in advance before starting postscript export. Here you can see two Postscript exports of the same drawing, one has linewidth 0.0 and the other 8.0 Postscript units. The Postscript output file name also can be changed. Everything that was said about linewidth applies to objects without width like: Lines, Circles and Splines. On the other hand some objects like Traces, Polylines, Polyline Arcs and Doughnuts have their own width defined in World Units in the drawing itself.