def rgtransform_to_matrix(rgM):
    """Convert :class:`Rhino.Geometry.Transform` to transformation matrix.

    Parameters
    ----------
    rgM : :class:`Rhino.Geometry.Transform`

    Returns
    -------
    :class:`list` of :class:`list` of :class:`float`.
    """
    M = [[rgM.Item[i, j] for j in range(4)] for i in range(4)]
    return M