def get_polygon_limits(polygon_list: list, offset=0.0):
    """Get the x,y,z limits from a list of polygons."""
    extreme_list = [p.extreme() for p in polygon_list]
    lim = list(zip(*extreme_list))
    xmin = min(lim[0]) - offset
    xmax = max(lim[1]) + offset
    ymin = min(lim[2]) - offset
    ymax = max(lim[3]) + offset
    zmin = min(lim[4]) - offset
    zmax = max(lim[5]) + offset
    return xmin, xmax, ymin, ymax, zmin, zmax