Attach, Scale, and Detach Underlays

You can add or remove references to underlays within drawing files, or you can change their relative size.

Attach Files as Underlays

You can attach a DWF, DWFx, DGN, or PDF file as an underlay to a drawing file.
Detach Underlay Files

Underlays that are no longer needed can be detached from a drawing file.
Unload Underlay Files

To improve performance, you can unload underlays from a drawing file.