def triangulate(dataset):
        """
        Returns an all triangle mesh.  More complex polygons will be broken
        down into triangles.

        Returns
        -------
        mesh : vtki.UnstructuredGrid
            Mesh containing only triangles.

        """
        alg = vtk.vtkDataSetTriangleFilter()
        alg.SetInputData(dataset)
        alg.Update()
        return _get_output(alg)