You can view file-specific information about the DGN underlays that are attached to a drawing. You can also load and unload underlays and perform other operations from the External References palette.
From the External References palette, you can view underlay information either as a list or as a tree. To control how the information is displayed in the External References palette, click the List View or Tree View button in the upper-right corner. The list view displays the name of each underlay in the drawing, its loading status, file size, date last modified, and search path. The tree view lists the underlays in a hierarchy that shows their nesting level within xrefs and blocks. The status, size, and other information are not displayed in the tree view.
In either view, you can display information about an underlay; attach or detach the underlay; unload or reload the underlay; and browse for and save a new search path.
The list view displays all underlays attached to the current drawing, but it does not specify the number of instances. It is the default view. You can sort underlays by category by clicking the column heading. Change the width of a column by dragging its border to the right or left.
The following information is displayed in the list view:
If AutoCAD cannot find an underlay, its status is listed as Not Found. A Not Found underlay is displayed as an underlay boundary in the drawing even if the DGNFRAME command is turned off. If the underlay is unreferenced, no instances are attached for the underlay. If the underlay is not loaded, its status is Unloaded. Underlays with a status of Unloaded or Not Found are not displayed in the drawing.
The top level of the tree view lists DGN files in alphabetical order. In most cases an underlay file is linked directly to the drawing and listed at the top level. However, if an xref or a block contains an attached underlay, additional levels are displayed.
View File Details or a Preview of the DGN Underlay
You can view DGN file details, including
You can display a preview of the DGN underlay instead of the DGN file details by clicking the magnifying glass icon in the upper-right corner of the area. The icon next to it restores the Details display.
