Short answer: IFC formats.
But is not like we use all of them in the office, We are a mixed MAC (VectorWorks) and PC(Revit) office, and I run ArchiCAD for my own stuff.
Is an interesting exercise (mostly trial-error-research-try again) playing with IFC files and its many flavors.
this could be a good subject for a new post.
Director @ BuilDigital
Using, Archicad Latest AU and INT. Revit Latest (have to keep comparing notes)
More and more... IFC.js, IFCOpenShell
All things Solibri and BIMCollab