public static BSpline3D ToBSpline3D(this ICurve swCurve, bool isClosed)
 {
     return(swCurve
            .GetBCurveParams5
                (WantCubicIn: false
                , WantNRational: false
                , ForceNonPeriodic: false
                , IsClosed: isClosed
                )
            .ToBSpline3D(isClosed));
 }