def scale_vector_xy(vector, factor):
    """Scale a vector by a given factor, assuming it lies in the XY plane.

    Parameters
    ----------
    vector : list
        XY(Z) components of the vector.
    scale : float
        Scale factor.

    Returns
    -------
    list
        The scaled vector in the XY-plane (Z = 0.0).

    Examples
    --------
    >>> scale_vector_xy([1.0, 2.0, 3.0], 2.0)
    [2.0, 4.0, 0.0]

    """
    return [vector[0] * factor, vector[1] * factor, 0.0]
