Inserts a DGN file as an underlay into the current drawing.
When you attach a DGN file as an underlay, you link that referenced file to the current drawing. Any changes to the referenced file are displayed in the current drawing when it is opened or reloaded.
The Select Reference File dialog box (a standard file selection dialog box) is displayed. Once you select a DGN file, the Attach DGN Underlay dialog box is displayed. After the file is attached, you can adjust and clip the underlay through the DGN Underlay Ribbon Contextual tab.
When a DGN file is attached as an underlay, its levels structure (layers) are combined into a single layer. The DGN underlay is placed on the current layer. To hide the DGN attachment, freeze the layer on which it was attached.