How is Rhino able to import dwg

There are few programs outside autodesk’s product line that are able to import dwg files without converting them to dxf first. I am wondering how is rhino able to do it?

Probably by reverse engineering the file format, as it is not an open/libre file format, but proprietary Autodesk.

Could someone please confirm it?

If that’s true would there be any chance for Rhino to release this work? It would be incredibly useful for others.

Rhino uses OpenDesignAlliance’s DWG library: https://www.opendesign.com/
McNeel was a founding member of the OpenDesignAlliance Customers | Open Design Alliance

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Perfect, thank you

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@fraguada a follow-up question would be why is it not available in Grasshopper?

Make a C# component that calls RhinoDoc.Import.

– Dale

You can also use the Params > Input > Import3DM component:

@fraguada true, I’ve tried that, but a lot of objects were lost using this method (blocks or blocks within blocks)

@dale thanks, I need to test it