Once you have created you 3D Polyline, exporting it’s an ArchiCAD task!
I mean in order to export the data you are not using ArchiForma anymore but the ArchiCAD standard procedure.
So, ArchiCAD will export the 3D data depending on the Save as… command you will choose.
I don’t know which kind of file formats Robot Millennium can import…
If it provides the users with a file format that ArchiCAD uses it shouldn’t be a trouble.
Of course anything depends on which kind of entities it can import and if this import matches with what you are looking for.
If, as I could suppose, you choice will be the DXF or the DWG format, then what I can say is that the ArchiForma 3D Polyline is just a “normal” GDL object so it should be exported as BLOCK entity.
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