In NX 12.0 there was a "Specify Origin Curve" option introduced in the "Section" group of the extrude menu.
What is this option used for?
The "Specify Origin Curve" option allows you specify which of the selected curves in the section string is the first curve in the extrude section, regardless of the order in which the curves were selected. The location and direction of the first curve of each section string is marked by a direction vector.
Specify Origin Curve is a function shared with Revolve. In Extrude command this ability only comes to play during Replace Feature mapping operations. where it helps to organized the mapping visually. Bringing more stable feature updates after feature remapping.
Notes and References
OS Version: 1064