About model and data exchange with 3rd party solutions: Revit, Solibri, dRofus, Bluebeam, structural analysis solutions, and IFC, BCF and DXF/DWG-based exchange, etc.
I use Archicad 12. I would like to be able to draw round ductwork, or import ductwork objects, including 18" dia. trunk lines with 8" run outs, transition elements and the like. Can anyone provide a source, especially freeware?