3D ClosedKeyCreator \ Create \ Spline \ 3D-Closed
Location: Create>Spline>3D Closed
Use this feature to create a 3D cubic parametric spline, or a true curve that begins and ends at the first point selected and with specified node locations and tangencies at its end points.
The slope and curvature are continuous at all points on the spline, and it appears as an unbroken loop.
Using the Function: