After a bit of digging answer has been found but for others, this only
applies to Architectural Desktop 2004 and NOT AutoCAD 2004:
You created a drawing in Autodesk® Architectural Desktop 2004 and need to
save the file in the AutoCAD® 2000 DWG format, however, this is not an
option in the Save Drawing As dialog box.
Intelligent objects in Autodesk Architectural Desktop 2004, such as walls,
doors and windows, are not compatible with previous AutoCAD DWG formats.
The option to save files in the AutoCAD 2000 DWG format was disabled in the
initial release of Autodesk Architectural Desktop 2004 to preserve the
integrity of object data. For this reason, all members of a project team
should utilize the same release of Autodesk Architectural Desktop to
maintain file interoperability.
However, there may be circumstances where you need to save an Autodesk
Architectural Desktop 2004 file in AutoCAD 2000 DWG format and if you
install Service Pack 1 for Autodesk Architectural Desktop 2004, this option
will be restored. While Service Pack 1 restores the option to save files in
AutoCAD 2000 DWG format, it is important to note that all Autodesk
Architectural Desktop objects will be saved as Proxy Objects only.
Consequently, to view the Autodesk Architectural Desktop objects in a
previous release of Autodesk Architectural Desktop or other AutoCAD-based
products, you must set the ProxyGraphics drawing variable to 1 before saving
Note: This can cause a dramatic increase in the file size.
Additionally, if you use a previous release of Autodesk Architectural
Desktop to open an Autodesk Architectural Desktop 2004 file that has been
saved in AutoCAD 2000 DWG format, a dialog box will appear with the
This application has detected objects from a newer version in this drawing.
Some commands will not be available.
Save this drawing from the original application as AutoCAD 2000 format
either with the AEC objects exploded, or with the ProxyGraphics turned on,
and attach it as an Xref in order to use it as a background.
In addition to this warning, a number of "ARX_ERROR: eNotThatKindOfClass"
messages will be repeated on the command line. Once the file is opened in
the previous release, all Autodesk Architectural Desktop commands will be
disabled for the remainder of the session.
Finally, when you use Autodesk Architectural Desktop to save files in
AutoCAD 2000 DWG format, a dialog box will appear with the following
Warning: This drawing may contain features that are not compatible with
earlier versions. Some information may be lost when saving to a previous
drawing format. See the ReadMe for details.
If you would like to preserve all of the information, save the file in the
If this action is not desired, you can use the AecFileSaveMessage command to
control whether the warning dialog box is displayed or not.
What we have is a conflict of interest. What you want is usable software and
the ability to work with others. What AutoDesk wants is your money. Your
productivity is of no importance to them as long as you keep your wallet
open. To be a good little Autodroid, you need to get AutoDesk behind you,
drop your pants, bend over and be willing to pay for the experience.