Simple Drawing Compatibility Method – Multiply Drawing Compatibility Method

AutoCAD SDI (Single Document Interface) System Variable

From the beginning of AutoCAD 2000 version, Autodesk makes the possibility of more than one drawings be opened with AutoCAD at the same time. They created a system variable to regulate it. This is SDI (Single Document Interface), which regulates to open only one or more drawings at the same time.

Why was it important?

In the old days not everybody had a strong computer, and it was not possible to open more drawings at the same time, or to handle them without problems. Although the base setting was to open more drawings at the same time, with this system variable it could be changed to single drawing compatibility. It means that if you open a new drawing, all the earlier opened drawings will be closed.

This setting possibility was available in AutoCAD at Settings panel System tab till the 2007 version.

Then there was a description also in the Help of the program. All imprints are disappeared from Help and Settings, as Autodesk mentioned it after SDI system variable specification. From this independently if we type it in the command line, the program will recognize it and we can set it.

Sometimes it happens that it is retooled, so I give you the settings of the AutoCAD SDI system variable.

AutoCAD SDI – Single drawing compatibility method

It limits the program to open only one drawing at once. If you delete this option, you can open more drawings at once. If few drawings are opened you can not turn on this option until you close additional drawings. (SDI system variable)

SDI system variable

Type: whole

Saved: system database

Started value: 0

It regulates that program runs with one or more interfaces.

0 – Turn on multidocument interface.

1 – Turn off multidocument interface.

2 – (Read only) Multidocument interface was denied because such an application was downloaded which did not support multidocument interface. Two values of SDI variable are not saved.

3 – (Read only) Multidocument interface was denied because user changed SDI variable to 1 and downloaded such an application which did not support multidocument interface. (SDI variable was changed to 1 before downloading.)  Value 3 of SDI variable is not saved.

If SDI value is changed to 3, it will be changed to 1, when application which does not support other drawings is deleted from memory.

Remark: SDI system variable will be removed from future version of AutoCAD. Now SDI works but it is not supported. Some commands and function do not work when you use single document interface.