Custom objects provide additional capabilities to the program and related products. When the application that created the custom object is not available, a proxy object is substituted in its place.
A custom object is a type of object created by an ObjectARX ® (AutoCAD Run-Time Extension) application, which typically has more specialized capabilities than standard AutoCAD or AutoCAD LT objects. Custom objects include parametric solids (AutoCAD ® Mechanical), intelligently interactive door symbols (AutoCAD ® Architecture), polygon objects (AutoCAD ® Map 3D), and associative dimension objects (AutoCAD and AutoCAD LT).
In addition to Autodesk, many software vendors use ObjectARX to write programs that create graphical and nongraphical custom objects that are useful in their AutoCAD based applications.
A proxy object is a substitute for a custom object when the ObjectARX application that created the custom object is not available to AutoCAD, AutoCAD LT, or other host applications. Later, when the application is available, the proxy object is replaced by the custom object.
Proxy objects have significantly reduced capabilities compared to their corresponding custom objects. The extent to which proxy objects can be edited is determined by the parent ObjectARX application. For example, operations such as erasing and moving an object, or changing object properties, may or may not be possible on a proxy object, depending on the application that created it.
When you open a drawing, you might see a Proxy Information dialog box. The dialog box tells you the total number of proxy objects in the drawing (both graphical and nongraphical) and the name of the missing application and provides additional information about the proxy object type and display state. You can use the dialog box to control the display of proxy objects.
An object enabler is a tool that provides specific viewing and standard editing access to a custom object in the host applications when the application that created the custom object is not present.
Object Enablers allow custom objects in a drawing to behave with more intelligence than proxy graphics. Object enablers also facilitate workgroup collaboration when using other Autodesk products.
If the ObjectARX application is not installed on your system, you can check for available Object Enablers on the Web. For example, if you receive a drawing that contains objects that were created in AutoCAD Architecture, but you don't have that application installed on your system, the AEC Object Enabler is downloaded so you can view those drawings as they were intended.
For a complete list of the currently available Object Enablers, go to the Autodesk Web site at http://www.autodesk.com/enablers.
If an application such as AutoCAD ® Map 3D was used to add a feature (object) classification to an object, you can view the classification in the Properties palette in the Class Name entry. If the object's classification is missing from the associated classification (XML) file, or if the associated classification file is missing, an exclamation mark is displayed in the Class Name entry. For information about what is required to create a feature classification, see the AutoCAD ® Map 3D documentation.
You can also use the Quick Select feature to select objects by their Class names and Class properties.