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.
AutoCAD uses zero length lines as points. These are translated as hotspots into ArchiCAD. I haven't checked this recently, but I pretty sure I've been seeing hotspots come in with xREF'd site plans lately.
