Archicad are yet to support improvements to IFC4 (that I know of anyway) and because it doesn't have nurbs you can produce files that won't work. But there are quite a few users that are finding the workflow working for them. If you observe problems, let me know and I'll try to advise.
Jon Mirtschin
Hi John,
Have you seen you can filter the blog on topics such as Archicad?
http://geometrygym.blogspot.com/search/label/Archicad
Archicad are yet to support improvements to IFC4 (that I know of anyway) and because it doesn't have nurbs you can produce files that won't work. But there are quite a few users that are finding the workflow working for them. If you observe problems, let me know and I'll try to advise.
Jan 13, 2013