code: def delaunay_2d(self, tol=1e-05, alpha=0.0, offset=1.0, bound=False):
          
          return PolyData(self.points).delaunay_2d(tol=tol, alpha=alpha, offset=offset, bound=bound)
docs: Apply a delaunay 2D filter along the best fitting plane. This
          extracts the grid's points and perfoms the triangulation on those alone.