Frequent tipster Leonid Nemirovsky of the Better Than Nothing AutoLISP site sends us a tip about using the DimBreak command to clean up the extension lines of dimensions.
"When using the DimBreak command, I noticed that if the Auto option is selected, the dimension line breaks for any AutoCAD object it crosses — lines, blocks, text/mtext, circles and squares — not just other dimensions or leaders. And all that can be done manually if desired."
Notes from Cadalyst Tip Patrol: The DimBreak command in AutoCAD "breaks" a dimension line where another object crosses it. It will also break extension lines. It doesn't actually break them; it makes them appear that they are broken so you can see the other objects. Start the DimBreak command, select the dimensions to break, and use the Auto option to automatically create breaks. Or you can use the Manual option to manually pick your break points. You can also use the Remove option to remove the breaks on a dimension.