Researchers experimented with drawing user interfaces in the air. The neat thing is that you can’t see this interface! You have to be aware of it by using your visual memory.
That sound’s very interesting for the scenario in the video to give driving directions. If you don’ have to be accurate in giving visual informations / drawing you don’t have to carry a inconvenient things like a cumbersome note pad with pen.
And if this augmented reality (AR) technology is decreasing itself in size and weight you probably would use the combination of AR-glasses with the ‘freehand drawing’ to be able to draw and see what you are drawing, everywhere. Than one is also able to draw in more than one planes – that’s (approximately) 3 dimensional!
[hpi.uni-potsdam.de: Imaginary Interfaces]