Civil 3d Xref -

In Civil 3D, External References (Xrefs) are essential for managing complex infrastructure projects by allowing users to link external drawings into a "master" file without significantly increasing its size

: Labels created locally on XREF objects will automatically update if the source geometry changes. Managing Display & Clipping civil 3d xref

: Click the Attach DWG icon (or right-click in the palette). Select your target file. Configure Insertion Settings : In Civil 3D, External References (Xrefs) are essential