AutoCAD: The XREF command.

Use the XREF (eXternal Reference) command to reference one drawing into another. The referenced drawing is often called a base drawing or simply an XREF. The concept is essential when you’re organizing a large set of drawings consisting (for example) of floor plans, ceiling plans, sections, title borders, etc.

 

A typical application.

A typical application of the XREF command involves the creation of “plot sheets.” Plot sheets are AutoCAD drawings which contain an XREF’d base drawing, such as a floor plan, which is viewed through a layout space viewport. Plot sheets also usually contain an XREF of the architect’s title border.

 

Example use of the XREF command.

  1. Draw a floor plan using standard AutoCAD drawing commands. Save the drawing in an accessible location (e. g., a shared drive). Close the floor plan.
  2. In a second drawing, type XREF. Right-click in the empty area of the panel to reference (“Attach”) the floor plan drawing into the model space of the plot sheet.
  3. In the layout space of the plot sheet, create a scaled viewport through which you can see the floor plan. Use the viewport to manage layers.
  4. Use the XREF command to reference a copy of the architect’s title border into the layout space. (A title border is an AutoCAD drawing containing project-specific information.) Title borders typically contain space for sheet-specific information such as a sheet number and name.

Note: Plot sheets can be composed to show multiple XREFs at multiple scales.

 

Overlay or Attach?

Every XREF is classified either as being attached or overlaid. Attached XREFs will “nest” into successive XREFs: You can XREF a drawing containing another overlaid XREF. Overlaid XREFs do not nest: if, in a new drawing, you attach an XREF containing an overlaid XREF, the overlaid XREF won’t appear in the new drawing. In the XREF dialog box, double-click on the word Attach (or Overlay) next to the XREF drawing name to change its status.

 

Common base point.

If you create a series of drawings such as floor plans, elevations, and sections, describing a single building, consider drawing each drawing such that the point (0, 0, 0) represents the same point in space in each drawing. This allows easy cross-checking of (for example) plans to sections by XREFing one into the other at (0, 0). Such cross-checking also works between floor plans – allowing easy verification of whether, for example, elevators, mechanical shafts, and exterior walls align between drawings.

 

Multiple users.

By default, AutoCAD will prevent other people on a network from opening a drawing if that drawing is XREFerenced into your drawing. If you wish to disable this feature, and allow other users to edit the XREFs, type OP; click on the Open and Save tab; under External References, set Demand Load to “Enabled with copy.”

 

Binding XREFs.

To “break the link” between an XREF and its host drawing, and to permanently insert the XREF within the host: in the XREF Manager dialog box, highlight an XREF and click Bind. Choosing Insert is equivalent to using the Insert command to copy an external .dwg file into the host drawing. Choosing Bind inserts the XREF into special new layers, intentionally keeping the XREF layers separate from the host drawing layers.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s