Hi Michael,
you are right, thats what i try to do. I just need a rough Nurbs model for a
cost estimate purposes. An these guys there can only deal with closed surfaces.
However, i will have to do a reconstruction of my model anyway, so they will have
to wait for the finished model.
With the non snapping objects: I got the solution here. The snapping was set to
elements which are not present in the isolated geometry. So it could not snap at all.
Best regards,
Heiner

Hi Heiner, yes re: non snapping - you must have been referring to center object snap on those ones. A closed and planar polyline curve will have a center snap at the centroid so that you can snap on to the center of things like square or rectangle polygons and things like that. If the curve is not planar that particular snap point won't be present though.

So that's probably just another side effect of some of the polygons being non-planar.

- Michael