Ref. Issue - 05 May 2008

Controlling Xref Display
You can control the display of xref layers so that you see only those layers you need. Several
features let you control the process of displaying xrefs, making it easier to see only part of an
xref and speeding up the display of very large xrefs.

Xrefs and dependent symbols
Dependent symbols are named items in a drawing, such as layers, text styles, dimension
styles, and so on. When you attach an xref, these symbols are listed in your current drawing.
For example, the Layer Control drop-down list displays the layers of the xref. Xref symbols
have the format xref_name|symbol_name. This system distinguishes xref symbols from
those of your current drawing and ensures that there are no duplicate symbols.

Xrefs and layers
You can turn on and off, or freeze and thaw, xref layers. You can also change an xref layer’s
properties in the Layer Properties Manager dialog box. By default, these changes are
retained. However, you can set the VISRETAIN system variable to 0 to discard these changes.
The next time you open the drawing or reload the xref, the original settings are restored.
Objects created on layer 0 do not take on the typical xref layer name format, but stay on layer
0. If objects in the xref are on layer 0 with the color and linetype set to ByLayer, they take on
the color and linetype properties of the current layer in the current drawing. If color and linetype
are set to ByBlock, then objects assume the current properties when the xref is
attached. If you explicitly set color and linetype, then objects retain those settings.