CAD applications often implement features or entities which are associative in nature, for example creating an extrude surface in AutoCAD 2011, by extruding a profile creates associative extrude surface. When you modify the profile the extruded surface will update itself to follow the profile. AutoCAD developers now can develop fascinating applications using new associative framework. There are APIs available in C++ as well as .NET to implement associative features in AutoCAD. You can download the latest ObjectARX to make use of associative framework. The associative framework in AutoCAD helps us to maintain relationship between objects. Relations are represented as hierarchical Networks of Objects, Actions and Dependencies between them. The core building blocks are: Action - Defines behavior or intelligence of application or feature. Dependency- Maintains associativity/ relations between objects and notifies changes on dependent objects. Network- The associative model Object- ...