There are three types of curves that can be constructed with the spline routines:
Open - This option creates an open ended curve. This means the curve starts in one location and ends in another.
Closed - This option creates a close ended curve. This means the curve starts and ends in the same location.
Line - This option differs from the Open or Closed options. It doesn’t use theoretical points but instead uses boundary points and creates straight lines within the boundary points, following the boundary points’ direction rules.