Yes, the X-Y plane is the default selection plane, but you can select and construct "off" the X-Y plane is you SELECT points/objects that are "off" the X-Y plane. What the option, that I mentioned, under Prefernces/Work Plane... does is LIMIT your selections TO the X-Y plane, period. It's as if all the points/objects NOT on the X-Y plane were on a visible yet non-selectable layer.
As for the "Associative Basic Curves", sorry for the confusion, but this was intended to be a replacement for the old "Basic Curves" function, which while we are not removing them from the system, we will be making them harder and harder to find.
John R. Baker, P.E.
Product "Evangelist"
NX Product Line
UGS Corp
Cypress, CA
Phone: 714-952-6032
FAX: 714-952-5758
John.R.Baker@ugs.com