public void CreatePline() { Point2d[] pt = new Point2d[4]; pt[0] = new Point2d(0, 0); pt[1] = new Point2d(10, 0); pt[2] = new Point2d(30, 20); pt[3] = new Point2d(-20, 50); Point2dCollection pts = new Point2dCollection(pt); ObjectId plineId = ModelSpace.AddPline(pts, 0); }