Often you would need to add an automatic process to your DWG drawing file save operation - e.g. to save the drawing without unnecessary block definitions (Purge), with the modelspace active, and/or with the thumbnail preview covering the whole drawing.
In such situations you can use the automatic save reactor Xanadu PreSave. After you load it (APPLOAD, ACADDOC.LSP), all standard drawing saves (using a command, keyboard shortcut, closing the window or closing AutoCAD) will be automatically preceded by the selected preset operations. The reactor parameters can be set with the PRESAVE command (dialog). You can also define other, custom actions performed before save. All settings are stored in the Registry - so they are valid for all drawings and all sessions.

The currently defined internal actions include:
- Zoom extents
- Set layer to "0"
- Switch to the Model tab
- Perform Purge (repeated)
You can download the Xanadu PreSave utility from www.xanadu.cz/download. There you can get also the Authorization code required for advanced functionality of PreSave.