def default_OTF(x1, x2):
    maxs = max(x1, x2)
    mins = min(x1, x2)
    otf = PiecewiseFunction()
    otf.add_point(mins, 0.0)
    otf.add_point(maxs, 0.2)
    return otf
Creates a default opacity transfer function.
dataset/ETHPy150Open enthought/mayavi/mayavi/modules/volume.py/default_OTF