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"nanoCAD is a well-proven DWG-compatible CAD program that includes AutoCAD-like APIs. It's totally free. No catches. No adware. No crippleware. No incessant nagging. Up until now, the free version has been the only version of nanoCAD offered to the USA. No doubt, the best value in the industry (even better than DraftSight [it lacks APIs in the free version])."
Exclusive: Evan Yares on nanoCAD USA - WorldCAD Access