ObjectARX & Dummies - http://arxdummies.blogspot.com/ Talk about programming using .NET framework and ObjectARX Autodesk API.
CADing && Coding - http://cadingandcoding.blogspot.com A learning resource for AutoCAD Programming and Customization. AutoCAD.Net programming with C#, VBA Programming, DIESEL Macros and AutoCAD Tips and Tricks.
Through the Interface - http://through-the-interface.typepad.com/ Site made by Autodesk member that contain information to ObjectARX API development and code samples.
ARX LT SDK - http://www.cadaware.com/ An extension to AutoCAD LT to enables the ObjectARX API as with the standard version of AutoCAD.
Py_acad - http://pyacad.sourceforge.net/ A free software module that makes it possible to extend AutoCAD with the Python programming language, in a similar way as with AutoLISP.
AutoCAD Exposed - http://www.manusoft.com/Resources/AcadExposed/index.stm Information about undocumented features of AutoCAD, such as commands, system variables, and functions of the ADS, ARX, and AutoLISP programming interfaces.
AutoCAD Developers Group Europe - http://www.adge.ch/ A non-profit association of software developers who are working on applications around AutoCAD.
Open Design Alliance - http://www.opendesign.com/ An association of CAD customers and vendors committed to promoting Autodesk's AutoCAD DWG drawing file format as an open, industry-standard format for the exchange of CAD drawings.
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