The three curtains are totally different in terms of making and aesthetics, but all three open vertically, draping the fabric from the bottom upwards through a system of cables and guide-rings sewn on the back.
That compactation allows the vertical opening even on stages of extremely low height and where lateral space is absent.
The Venetian curtain can also be opened without compactation, that is, lifting the curtain as a whole with the Fly opening system. In that case it becomes a simple Fly curtain with vertical fullness.
The vertical fullness allows the Venetian curtain to be opened also with the shaped lower edge, a characteristic it shares with the Austrian curtain.