Recommendation
ObjectARX and ObjectDBX modules
Autodesk is committed to supporting both DWG and DXF storage formats as logically equivalent in content.
DWG is a proprietary binary format that offers superior I/O performance, while DXF is a published format intended to both minimize application parsing requirements and maximize compatibility with previously released products.
Applications are not required to publish the meaning of DXF data fields, and are free to encrypt their DWG and DXF data as they see fit for security purposes, as long as encrypted data is written and read in compliance with the published I/O rules for DWG and DXF.
The DWG and DXF representation must be sufficient to restore the object state from the file in a future RealDWG® host application session. See the ObjectARX Developer's Guide for details.
Finally, AcDbObject::decomposeForSave() must also be supported to allow saving to previous DWG and DXF versions. The default behavior for this member is sufficient support.
If your application is loaded, then you are responsible for filing out object information. When the application is unloaded, proxy information is written out.