Export > 3D

(2D only) Opens the Save 2D As 3D dialog box, which is used to save the active 2D DGN file or active cell library (if any) as a 3D file.

Save 2D as 3D dialog box

Key-in: MDL LOAD CNVDGN

If the active DGN file is 3D, this item is Export > 2D.