public Polyline Poly2dTiPolyline(Entity entity, double width) { Point3dCollection point3dCollection = new Point3dCollection(); if (entity is Polyline2d) { Polyline2d polyline2d = (Polyline2d)entity; polyline2d.GetStretchPoints(point3dCollection); } else if (entity is Line) { Line line = (Line)entity; line.GetStretchPoints(point3dCollection); } return(this.Poly2dTiPolyline(this.Point3dCollectionTo2d(point3dCollection), width)); }