I have been playing with a AS3 platform game and wondered how to make jump-through-platforms like the ones in Super Mario Bros. I found out that you can create a LineData body and set doubleSided to false. This allows you to jump through the platform on your way up.

// a, b, infinite, doubleSided
var lineData : LineData = new LineData(
    new Point(0,0),
    new Point(100,0),
    false,
    false
);

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