DWG to PDF:
Acrobat XI can convert DWG files directly into PDF format without the user needing AutoCAD installed on their computer. If there is no layout already setup then I have found it to be a bit hit-and-miss with the results; especially the modelspace.
Right-click on the DWG file and choose 'Convert to Adobe PDF'.
You can also view and print DWG files and output to PDF format with the free Autodesk® DWG TrueView™ software. This is probably your best bet.
PDF to DWG:
With regards to converting PDF to DWG then I'm afraid this is outside of Acrobat's functionality. There are a lot of PDF to DWG programs out there but none I would recommend particularly.
Adobe Illustrator and CorelDRAW can convert PDF's to DXF/DWG but please be aware that PDF's do not store the hatches, linetypes, line styles, plot styles etc. Therefore whilst they will export to DXF/DWG you will find that:
- All lines will become splines (but use PEDIT to convert to polylines)
- Hatches will fragment into seperate lines (no easy workaround)
- Dashed lines will fragment (to join selected 'dashes' use PEDIT > MULTIPLE > JOIN (set fuzz distance to slightly exceed gap to join, set JOINTYPE to Add)