Now in reality they don´t... but in Pro/E they do. In complex assemblies this makes the calculation of global interference quite useless - lots of them, always, so that a real one can easily be missed. I wonder if - perhaps in WFx - Pro/E will ever let go the bad habit of handling threads as "cosmetics" only. Or do you WF1 and WF2 users still see interference between nuts and bolts and their respective threads? Any possibility of marking these as nonsense? Just curious. Walther