Raymond Foren sent this tip to add function calls to entities, which he uses in AutoCAD 2008.
1. In the CUI, under Double Click Actions (DCA), select an entity type you do not use in your drawings.
2. Add a Command line to launch a function or command.
3. Double click the entity and launch the function.
Raymond writes, "I drew a small circle in our DWT file at the edge of the title block. Then I converted the circle to a region. (We generally do not use regions in our work.) In the DCA menu, I assigned the following code to the region:
^C^C^C(if (not Action) (Load "Action")()) (Action);
"Whenever anyone double-clicks the small circle, the command is run. Just remember, any region used in your DWG file will react to this command. This command launches a dialog box to select options for display in the title block. Also, we use shared menus that reside on our server.
"You can assign commands to entities and use to display geometry of an arc, display the inverse of a line, display attribute information of blocks, and the list is limitless!"
NOTES FROM CADALYST TIP PATROL: Great tip! The user just has to determine which entities must be "sacrificed" to use this procedure. This tip can lead to a lot of efficient time-saving ideas. Thanks, Raymond.
Another Tip Patrol member agrees this is a good tip, but offers this caution: This is one of a group of customizations by which users, if they are not careful (careful in their documentation as well as in a professional sense), can customize their system to the point at which it becomes "myCAD" and not AutoCAD. Customizing the short-cut keys, toolbars, palettes, (in 09 the Ribbon) -- heck even customizing the PGP -- all allow the user to create a personal and idiosyncratic work environment.
Creating double-click commands for (typically in your usage or your firm's) unused entities is one more (double-edged) tool. In a sense, it is a method of REDEFINING or RENAMING commands. If users do so, they will always need to document their changes (on paper as well electronically) and -- if in a multiuser firm or as a visiting contractor -- be prepared to quickly (and easily) change things back to "normal."
Customization should always be balanced with its utility and its impact on one's skill set. A highly customized and thereby "personal" environment may make you much less functional (and marketable) to an outside employer!