生成SPLINE

                Point3dCollection pts = new Point3dCollection();
                pts.Add(pP5, pP7, pP9, pP8, pP6);

                //设置向量
                Vector3d vecTanStart = new Point3d(0.5, 0, 0).GetAsVector();
                Vector3d vecTanEnd = new Point3d(-0.5, 0, 0).GetAsVector();
                Spline spline = new Spline(pts, vecTanStart, vecTanEnd, 4, 0.0);
                zDB.AddToCurrentSpace(spline);