Tessellates surfaces.

    .. note:: Helper function required for ``multiprocessing``

    :param elem: surface
    :type elem: abstract.Surface
    :param update_delta: flag to control evaluation delta updates
    :type update_delta: bool
    :param delta: evaluation delta
    :type delta: list, tuple
    :return: updated surface
    :rtype: abstract.Surface

def process_tessellate(elem, update_delta, delta, **kwargs):
    """ Tessellates surfaces.

    .. note:: Helper function required for ``multiprocessing``

    :param elem: surface
    :type elem: abstract.Surface
    :param update_delta: flag to control evaluation delta updates
    :type update_delta: bool
    :param delta: evaluation delta
    :type delta: list, tuple
    :return: updated surface
    :rtype: abstract.Surface
    """
    if update_delta:
        elem.delta = delta
        elem.evaluate()
    elem.tessellate(**kwargs)
    return elem