Other Differences between External References and Blocks

Other Differences between External References and Blocks
Here are a few other differences between Xrefs and inserted blocks that you’ll want to keep in mind:
◆ Any new layers, text styles, or linetypes brought in with cross-referenced files don’t become
part of the current file. If you want to import any of these items, you can use the Xbind command
(described in Chapter 15).
◆ If you make changes to the layers of a cross-referenced file, those changes aren’t retained
when the file is saved unless you checked the Retain Changes To Xref Layers option in the
Open And Save tab of the Options dialog box. This option, found in the External References
(Xrefs) group, instructs AutoCAD to remember any layer color or visibility settings from one
editing session to the next. In the standard AutoCAD settings, this option is on by default.
TIP Another way to ensure that layer settings for Xrefs are retained is to enter Visretain↵ at the
Command prompt. At the New value for VISRETAIN <0>: prompt, enter 1.

Importing Blocks, Layers, and Other Named Elements from External Files
You can use the Xbind command to import blocks and other drawing components from another file.
First, use the External References palette to cross-reference a file; type Xbind at the Command prompt.
In the Xbind dialog box, click the plus sign next to the Xref filename, and then select Block. Locate the
name of the block you want to import, click the Add button, and click OK. Finally, open the External References
palette, select the Xref filename from the list, right-click, and select Detach to remove the Xref
file. The imported block remains as part of the current file. (See Chapter 15 for details on importing
drawing components.) You can also use the AutoCAD DesignCenter to import items from external files.
DesignCenter is described in Chapter 27.
The Tool Palettes window give you access to frequently used blocks and hatch patterns that reside in
other drawings. You can open the Tool palettes by clicking the Tool Palettes icon in the Standard toolbar.
In the standard AutoCAD installations, the Tool Palettes window is configured with sample 3D commands,
blocks, and hatch patterns that you can drag and drop into your current drawing. Select a tab for
the Tool palette that contains the block or pattern you want, and then click and drag the item into your
drawing. In the case of hatch patterns, click and drag the pattern into an area that is bounded on all sides
by objects. When you’re ready to customize the Tool Palettes window, you do so by clicking and dragging
objects or tools into a new or existing palette. See Chapter 27 for more on customizing tool palettes.
◆ To segregate layers in Xref files from layers in the current drawing, the Xref file’s layers are
prefixed with their file’s name. A vertical bar separates the filename prefix and the layer
name when you view a list of layers in the Layer drop-down list or the Layer Properties
Manager dialog box (as in Unitxref | wall).
◆ You can’t explode Xrefs. You can, however, convert an Xref into a block and then explode it.
To do this, select the Xref in the External References palette to open another dialog box that
offers two ways of converting an Xref into a block. See the section “Other External Reference
Options” later in this chapter for more information.
◆ If an Xref is renamed or moved to another location on your hard disk, AutoCAD won’t be
able to find that file when it opens other files to which the Xref is attached. If this happens,
you must select the path in the Found At field in the External References palette and then
click the Browse button (the ellipses) to tell AutoCAD where to find the cross-referenced file.
WARNING Take care when retargeting an Xref file with the Browse button. The Browse button
can assign a file of a different name to an existing Xref as a substitution.
◆ Xref files are especially useful in workgroup environments in which several people are
working on the same project. For example, one person might be updating several files that
are inserted into a variety of other files. Using blocks, everyone in the workgroup would
have to be notified of the changes and would have to update all the affected blocks in all the
drawings that contained them. With cross-referenced files, however, the updating is automatic;
you avoid confusion about which files need their blocks updated.