About External References

The Drawing Management feature uses external references (xrefs) as a means to create a project and maintain it. Elements are referenced into constructs, constructs are referenced into views, and views are referenced into sheets. The mechanism of referencing is identical to the regular AutoCAD External References Management feature. However, the background methods employed have additional features.

Xrefs that are created in drawing management can automatically make use of project data, while those that are created manually through the xref palette or command line cannot. For example, a construct that is placed on a specific level will use that level's elevation data (as defined by the project) to control the Z-axis insertion point when being xrefed into a view.

If you are working in a project environment, the best practice for referencing project drawings into other project drawings is to use the Project Navigator rather than the standard AutoCAD Xref Manager. The AutoCAD Xref Manager cannot differentiate between project drawings and non-project drawings. If you reference a non-project file into a project file by mistake, you cannot use the full Drawing Management functionality on that file.

Whenever you define a project drawing on the Project Navigator, an accompanying XML file is created. The XML file is vital for the project. Under no circumstances should you delete it (unless you are deleting the entire project). That XML file contains:

• information about level and division assignments
• viewport and content information appropriate for the type of drawing

Keep these considerations in mind when working with a project:

• Do not delete any XML files generated by the Drawing Management feature. They are vital for the project.
• Use the Project Navigator to create, modify and reference project files within the project. If you want to use existing non-project files in a project, convert them to project files first.
• Drawing Management supports the use of relative paths for external references. In the project setup, you can decide whether to use full paths or relative paths. Working with relative xref paths makes moving the project and transmitting it easier and reduces the need to repath the project.
  Note: Changing full xref paths to relative xref paths or relative paths to full paths in an existing project will change existing paths. An exception is if the xref path points to a location that is outside the project folders or is otherwise not supported by relative paths.