Whenever you open a Bentley SewerCAD -based drawing file in AutoCAD, the Bentley SewerCAD model server will start. The first thing that the application will do is load the associated Bentley SewerCAD model (stsw) file. If the time stamps of the drawing and model file are different, Bentley SewerCAD will automatically perform a synchronization. This protects against corruption that might otherwise occur from separately editing the Bentley SewerCAD model file in stand-alone mode, or editing proxy elements at an AutoCAD station where the Bentley SewerCAD application is not loaded.

The synchronization check will occur in two stages:

• First, Bentley SewerCAD will compare the drawing model elements with those in the server model. Any differences will be listed. Bentley SewerCAD enforces network topological consistency between the server and the drawing state. If model elements have been deleted or added in the .stsw file during a Bentley SewerCAD session, or if proxy elements have been deleted, Bentley SewerCAD will force the drawing to be consistent with the native database by restoring or removing any missing or excess drawing custom entities.
• After network topology has been synchronized, Bentley SewerCAD will compare other model and drawing states such as location, labels, and flow directions.

You can run the Synchronization check at any time using the following command:

STMCSYNCHRONIZECSDWSYNCSERVER

Or by selecting File > Database Utilities > Synchronize Drawing.