Saving to earlier versions in AutoCAD2004

After a bit of digging answer has been found but for others, this only applies to Architectural Desktop 2004 and NOT AutoCAD 2004:

Issue

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.

Solution

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 the file.

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 following warning:

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:

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 current format.

If this action is not desired, you can use the AecFileSaveMessage command to control whether the warning dialog box is displayed or not.

And so goes the tale of another AutoDesk forced upgrade plan.

Aye, that's progress for you!

This is productivity?! Bah!