More FreeCAD dxf export options...
I did some more work on the dxf exporter, now it begins to behave pretty accurately. You can now set an option in the preferences screen, in order to export 3D objects to polyface meshes. This is not the ideal way to export FreeCAD 3D objects, because they will be turned into meshes, so you'll loose important data such as curved surfaces and solid behaviour, but it is the only way to put 3D into a dxf file available to us as long as the ACIS format is kept closed and undocumented.
The other fix I did is to make the way to export 2D Drawing pages to dxf format work better. We now have fairly precise results when exporting such pages. The only thing you need to do is to select a page object, hit File->Export and specify a .dxf filename. There are still some glitches, some objects don't get drawn at the correct scale, etc... But the result is usable already. Below is an example of what you can expect to obtain:
The objects in the FreeCAD viewport
The same objects placed on a Drawing sheet
The sheet exported as dxf and opened in LibreCAD