cad.net 依照旧样条曲线数据生成一条新样条曲线的代码段. spline生成

                        Spline spl = entity as Spline; //拿到旧的spline图元...

                        //样条曲线生成条件
                        var controlPoints = new Point3dCollection();
                        for (int i = 0; i < spl.NumControlPoints; i++)  //控制点 
                        {
                            controlPoints.Add(spl.GetControlPointAt(i));                           
                        }
                         
                        NurbsData nu = spl.NurbsData;
                        entnew = new Spline(spl.Degree, spl.IsRational, spl.Closed,
                            spl.IsPeriodic,  //周期性  
                            controlPoints,   //控制点 
                            nu.GetKnots(),   //节点
                            nu.GetWeights(), //权重
                            nu.ControlPointTolerance,  //控制点容差
                            nu.KnotTolerance           //节点容差
                            );