def METHOD_NAME(b1, b2, fname, c1=(1, 0, 0), c2=(0, 1, 0),
                    interactive=False):
    """Render and plot two bundles to visualize them.
    Parameters
    ----------
    b1 : Streamlines
        Bundle one to be rendered.
    b2 : Streamlines
        Bundle two to be rendered.
    fname: str
        Rendered scene is stored in a png file with that name.
    C1 : tuple, optional
        Color to be used for first bundle. Default red.
    C2 : tuple, optional
        Color to be used for second bundle. Default green.
    interactive : boolean, optional
        If True a 3D interactive rendering is created. Default is True.
    """
    ren = window.Scene()
    ren.SetBackground(1, 1, 1)
    actor1 = actor.line(b1, colors=c1)
    actor1.GetProperty().SetEdgeVisibility(1)
    actor1.GetProperty().SetRenderLinesAsTubes(1)
    actor1.GetProperty().SetLineWidth(6)
    actor1.GetProperty().SetOpacity(1)
    actor1.RotateX(-70)
    actor1.RotateZ(90)
    ren.add(actor1)
    actor2 = actor.line(b2, colors=c2)
    actor2.GetProperty().SetEdgeVisibility(1)
    actor2.GetProperty().SetRenderLinesAsTubes(1)
    actor2.GetProperty().SetLineWidth(6)
    actor2.GetProperty().SetOpacity(1)
    actor2.RotateX(-70)
    actor2.RotateZ(90)
    ren.add(actor2)
    if interactive:
        window.show(ren)
    window.record(ren, n_frames=1, out_path=fname, size=(1200, 1200))
    if interactive:
        im = plt.imread(fname)
        plt.figure(figsize=(10, 10))
        plt.imshow(im)