Microstation Design File Format (DGN)

DGN is the internal format used by Bentley Systems Inc.’s MicroStation, a CAD program. It is well documented and standardised, so it may also be used as a transfer standard. DGN files contain detailed display information. The most common way to store attributes is to place them in an external database file and record links in the MSLINK field-a data item carried for each element in the DGN file.