The Microsoft ® Foundation Class (MFC) library allows a developer to implement standard user interfaces quickly. ObjectARX ® applications can be created to take advantage of the MFC library. The ObjectARX environment provides a set of classes that a developer can use to create MFC-based user interfaces that behave and appear as the built-in Autodesk user interfaces. This section discusses how to use the MFC library as part of an ObjectARX application and how the AutoCAD ® built-in MFC system can be used to create dialogs that behave and operate like AutoCAD.