Q. Where can find OMF SDK?
A. OMF SDK is posted on the ADN extranet https://adn.autodesk.com, the members only site.
After logged into the ADN extranet, go to "Software & Support" >> AutoCAD Architecture >> Download >> Object Modeling Framework (OMF). Follow the link and accept the license agreement. It will take you to the download page.
Note: OMF requires a separate license agreement and is provided to the member of ADN only.