Except for traditional CAD software like AutoCAD, users may find special utilities which allows users to process plotter graphics saved in Hewlett-Packard formats (.hpg, .hpgl, .hpgl2) and save it as 2D CAD drawings like DXF or DWG.
Convert HP Graphics Language plotter file to AutoCAD DXF Drawing Exchange Format.
We found 2 software records in the database related to .hpg to .dxf file format conversion.
Microsoft Windows software - convert hpg to dxf on Windows
Leading 2D and 3D CAD development software from Autodesk
Convert from hpg file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned hpg to dxf. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A HPGL2 to DXF Converter