def read(*parts):
    """
    Build an absolute path from *parts* and and return the contents of the
    resulting file.  Assume UTF-8 encoding.
    """
    with codecs.open(os.path.join(HERE, *parts), "rb", "utf-8") as f:
        return f.read()
def forcedens_surface(fdens, ax=0):
    if ax == 0:
        _create_3d_axis()
        ax = plt.gca()
    xpos = [p for p in fdens.positions[0]['X']]
    ypos = [p['position'] for p in fdens.positions]
    z = 1e-3*np.array([p['FN']
                       for p in fdens.positions])
    _plot_surface(ax, xpos, ypos, z,
                  (u'Rotor pos/°', u'Pos/°', u'F N / kN/m²'))