"if you have a rail curve with 5 control points and one with 500 control points both with the same shape and parameterization they will both give the same sweep result"

Thanks! Exactly what I was looking for.

"I use rebuild or reconstruct particular for the fillet-sweep-splines, for the patch connecting I need the normal edges of the patches, without any rebuild."

Thanks for that. That's pretty much how I do it now. Much appreciated!

You are avisuospatial genius! I remember a thread on this forum in which the possibility of making a car in Moi was discussed. You have settled the argument.

could you share your blueprints ?