The script emulates an HP DraftPro plotter (D size), with a plotting area
of 34,000 x 22,000 units with the origin in the center.
HPGL polylines (PA,PR), arcs (AA,AR) etc.
are mapped to IndexedLineSet in VRML, at z=0. Scaling commands (SC) in HPGL
are not mapped to VRML Scale; rather, the HPGL input is scaled
Labels (LB) are converted to AsciiText.
Color assignments for the pens may be given on the command line. A typical
command might be:
Not everything has been tested.