WALKING through walls is no longer a feat peculiar to ghosts. Virtual environments can now use sheets of fog as screens that people can physically jump through to get from one scenario to another, or out of the environment altogether.
Anyone using a virtual reality simulation is usually confined to a small room, with images back-projected onto canvas or plastic walls. But because the walls are so fragile, they are easily damaged if people knock into them, says Ismo Rakkolainen, a computer imaging expert at Tampere University of Technology in Finland.
So he came up with the idea of fog walls, which can鈥檛 get damaged. The fog wall is made from dry ice pumped between two layers of fast-moving air a centimetre apart. These keep the fog layer flat and smooth.
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Rakkolainen has turned his fog walls into realistic-looking walls using standard virtual reality projectors. On some, he projected moving scenes. 鈥淵ou can get good effects-images just float in the air,鈥� he says. 鈥淵ou can touch them, but you don鈥檛 feel anything.鈥�
Using fog walls to create virtual environments means that people can ditch the joystick or dataglove and physically walk around. When they want to enter another virtual room, they simply walk through the wall. Another possible application for them could be as giant walk-through adverts in shopping malls, he suggests.