In the CAD drawing structure, you can distinguish a main drawing and one or more xref drawing files.

In your drawing definition, to identify layers in a drawing, the following convention is used:

This approach ensures that layer names are unique, but it also means that the CAD drawing definition cannot be used for other drawing structures that contain xref drawings with different file names and identical layer structures.

To simplify using a drawing definition for importing your drawings this convention has now been extended by using a wildcard character (*).

In your drawing definition, when clicking the Refresh drawing structure action, a list of wildcard layers is generated and you will be able to choose from the available options (example):

For each layer in the main drawing and the xref drawings in the current drawing structure, an additional layer consisting of the base layer name prefixed with an asterisk (*) character is generated. Doing so, ensures that CAD drawing definitions that reference xref layers can be reused across your drawing structure.

These wildcard layers should uniquely identify a layer that occurs in either the main drawing or in exactly one of the xref drawings referenced by the main drawing.

When encountering drawings with the same layer name, the CAD verification process checks for these occurrences and will flag these when encountered so that appropriate action can be taken (amending the drawing or the drawing definition).