To Clip an Xref

Select an xref.
Click External Reference tab > Clipping panel > Create Clipping Boundary.
If prompted, specify yes to delete any existing boundary.
Select a polyline or specify a rectangular or polygonal clipping boundary. Specify the corners or vertices of the boundary.
(Optional) Use the Invert Clip option to change the area to be hidden from outside to inside the clipping boundary.
The xref is clipped based on the area that you specified.

Note: You can use DGNCLIP, DWFCLIP, PDFCLIP, or IMAGECLIP to clip their corresponding attachments: DGNATTACH, DWFATTACH, PDFATTACH, or IMAGEATTACH.