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drawing B. If you attach drawing A as an external reference to drawing B, the
PDF underlay that was already attached to drawing A is also be present.
All of the property settings made to the underlay in the external reference,
such as clipping boundaries, appear as they do in the parent drawing.
See also:
Attach and Detach Referenced Drawings (page 644)
Detach PDF Underlays
Underlays that are no longer needed can be detached from a drawing file.
When you detach an underlay, all instances of the underlay are removed from
the drawing, and the linking path to the file is removed.
To hide the display of an underlay temporarily, you can unload it rather than
detach it. This action preserves the underlay location for reloading later.
NOTE Erasing an individual instance of an underlay is not the same as detaching
it. An underlay must be detached to remove the link from your drawing to the
file.
Unload PDF Underlays
To improve performance, you can unload underlays from a drawing file.
When you do not need an underlay in the current drawing session, you can
improve performance by temporarily unloading it. Unloaded underlays are
not displayed or plotted. Unloading an underlay does not remove its link. If
you do not have sufficient memory to open multiple underlays in a drawing,
underlays are automatically unloaded.
Work with PDF Underlays
You can control the display of layers, use object snaps, and adjust display
settings with attached underlays.
672 | Chapter 11 Share Data Between Files