Using Xref Data in Surfaces

Externally referenced data in a surface imposes some usage limitations.

Using a standard AutoCAD Xref operation can be a convenient way to bring a surface from one drawing into another drawing. Doing this is great for visualization purposes, but some limitations apply to the use of editing commands with xref data. For example, you can use REFEDIT to select polylines within an xref drawing and temporarily add them to a surface as contours, breaklines, or boundaries. However, after you exit the REFEDIT mode, the link between the surface and the data becomes invalid, so it is lost after a surface rebuild operation and the surface does not react to changes in that data. To overcome this problem, the surface keeps a list of the polyline points instead of the polyline's object ID. As a result, the surface can be rebuilt, but it will always use the xref data exactly as it was when it was added to the surface.

For more information, see the AutoCAD help topic "Edit Selected Objects in Referenced Drawings and Blocks."