I’ve previously discussed how to use background masks with annotative text. Now I want to talk about using background masks in block attributes. Using the ATTDEF command, you create an attribute, but once it is created, there doesn’t appear to be any way to apply a background mask. The trick is to use multiline attributes.

Checking “Multiple lines” makes the “Default” value editable only by clicking on the ellipses.

If you click on these and type in your text (you can type just one line if you want), you can then highlight and right-click on your text and select “background mask” and apply the background mask settings.
Check “Use background mask”. I usually set the border offset factor to 1.2 or so, and the fill color to “use drawing background color”.

Hey
your info are exactly what i need but when i open my attribute definition windown,
i have only the first 4 options: invisible, constant. verifyn and preset. the other 2 that appears on yours (lock position and multiple lines) does not show on mine.
i am using cad 2005
are you using a newer version? how can i find the multiple lines option on mine? thank you
i will be waiting for your email
You need a newer version of AutoCAD. I think I was using 2008 when I wrote this, and it might be available in 2007.
I was searching for the same answer. I’m running AutoCAD 2007 and the multiline option is not an option in ATTDEF. So, you must be using 2008 or newer.
Not recommended unless you and everyone using your attribute blocks use autocad 2009 and above.
I had to return my blocks to single line attributes with a dinamically stretchable wipeout to be able to set a mask for the block text.
http://discussion.autodesk.com/forums/thread.jspa?threadID=559021
http://discussion.autodesk.com/forums/thread.jspa?messageID=6273009&