public static NurbsCurve ToRhino(DB.CylindricalHelix helix) { var nurbsCurve = NurbsCurve.CreateSpiral ( AsPoint3d(helix.BasePoint), AsVector3d(helix.ZVector), AsPoint3d(helix.BasePoint) + AsVector3d(helix.XVector), helix.Pitch, helix.IsRightHanded ? +1 : -1, helix.Radius, helix.Radius ); nurbsCurve.Domain = new Interval(helix.GetEndParameter(0), helix.GetEndParameter(1)); return(nurbsCurve); }