Class Hierarchy
AcRxObject AcGiDrawable AcDbObject AcDbUnderlayDefinition AcDbDgnDefinition AcDbDwfDefinition AcDbPdfDefinition
C++
class AcDbUnderlayDefinition : public AcDbObject;
File
dbunderlaydef.h
Description
This abstract class handles the linkage to external underlay content. Underlays are similar to raster images, except that users can snap to the content of an underlay.
An AcDbUnderlayDefinition object is referenced by zero or more AcDbUnderlayReferences. The AcDbUnderlayReference class is responsible for the placement of content within the drawing, while the AcDbUnderlayDefinition class handles the linkage to the underlay content. Instances of AcDbUnderlayReference-derived concrete classes are inserted in a block table record. Instances of AcDbUnderlayDefinition-derived concrete classes are inserted into a dictionary within the named object dictionary.
Links
AcDbUnderlayDefinition Methods
See Also
AcDbUnderlayReference