The JTB OffsetInXref app can be used with Autodesk® AutoCAD® to enable the OFFSET command to work with line contents of blocks and externally referenced drawings, associated arrays, dimensions, and tables.
Once loaded, the standard OFFSET command will work with blocks and externally referenced content: instead of responding "Cannot offset that object", the app will automatically copy the selected object into the current drawing, allowing it to participate with the OFFSET command. The lowest-level object will be selected, if part of a nested Xref or block, but some objects - such as Hatches - will still cause the "Cannot offset that object" prompt to be displayed. All objects copied temporarily into the drawing will be erased automatically at the end of the OFFSET command. The app can either have the OFFSET command create geometry on the current layer (the default) or the source layer. The XOFFSETLAYER command allows the configuration of this option.
Note: This app uses a custom installer (and not the standard App Store installer).