In many cases (computer graphics, machine learning, ta analysis) we need normalized values. Smooth step is one of the possible ways to do it
It belongs to the family of sigmoidal (clamping in this case, since this indicator, as is, is not used for interpolation) functions, and is producing a sub-set of what is the built in stochastic, except that I kept it in its original range of 0 to 1 and that it filters out some values that stochastic produces. Also, this indicator can use all the usual prices (not just the close/close or low/high/close)
Recommendations:- You can use it the same way as stochastic built in indicator