AutoCAD has many ways to select objects, but there is no straightforward method of performing an inverse selection. However, if you own a full copy of AutoCAD and you have some idea of coding then there is always a way to do this via programming.
AutoCAD can be programmed in several ways, but many of AutoCAD’s tools are written in the venerable language of Lisp. This is just a simple language that can be entered as shown below in a simple text editor like Windows Notepad. Save this file as “SAB.LSP”, load it into AutoCAD via the Appload command, adding it to the start-up suite if necessary.
Select your desired elements with AutoCAD’s ‘Select’ command using a window or crossing polygon.
Once selected cancel the selection and then run the newly created SAB routine.
The code above simply resets the selection buffer, selects everything within the document and then removes the previous selection set, leaving an inverse selection remaining. These elements can then be deleted or edited as desired.