A DWF (Design Web Format) file is a highly compressed file format that is created from a DWG file. You can attach a DWF file as an underlay to a drawing file. By attaching a DWF file, you can reference it without increasing the drawing file size.
You can attach or detach a DWF underlay (a DWF file reference) to drawing files. You can also change the position, scale, and orientation of DWF underlays.
After a DWF underlay is attached to a drawing, you can modify its position, scale, or rotation, and you can use DWF object snaps to locate objects relative to the objects in the DWF underlay.
You can control the layers, adjust the appearance, or specify clipping boundaries in a DWF underlay.
You can view and manipulate DWF underlays and change paths to underlays in the External References palette.