The Mapping Specification for CAD are standards for coding information in a (.dwg) or (.dxf) files to read, create and edit GIS attribute and ESRI coordinate system information. These standards utilizes (.dwg) or (.dxf) data structures to work with GIS data and provide an interoperable platform to work and share data across GIS and CAD platform. It's a standard programming structure to embed GIS schema, attribute data and a coordinate system in to (.dwg) or (.dxf).
MSC implementation allows users to work with GIS attribute information without altering CAD standards. This is beneficial for GIS and CAD workflow to create organized feature classes using existing CAD standards. Developers can choose from AutoLISP or the ObjectARX programming environment using C++, C#, or VB .NET.
Using the Esri developer symbol
Developers creating applications for any of the AutoCAD products by Autodesk are permitted to use the developer prefix ESRI_ for named objects as they are described in this specification.
The Open Design Alliance
Esri is a member of the Open Design Alliance (ODA) and uses the Teigha development platform to build CAD interoperability into ArcGIS. Similarly, developers implementing the Mapping Specification for CAD must use methods supported by the Teigha libraries to ensure interoperability with ArcGIS Desktop. One example is the limited support for conditional operators used to filter DWG objects.