2. Back to Cad Dwg to PDF http://www.backtocad.com/ - Use Overkill - AutoCAD command removes small and overlapping lines.
3. Bentley Flattener - does not do meshes
4. Flatshot - AutoCAD command that does solids
5. Flatten - AutoCAD command
6. -exporttoautocad - proxy AEC objects exploded into basic AutoCAD objects (solids)
7. MicroStation - Plot to Hidden line 2d. Only works on plan views. Open the model with MicroStation. Set your view display depth. Turn hidden lines on if needed. Use File > Export > Visible Edges… to create a 2D .DGN file. Open the 2D .DGN file with MicroStation and use File > Export > DGN, DWG, DXF… to create the .DWG file. Use the .DWG file to add drawing border, annotation, etc