Grabbing in the Air

The idea behind the grabbing-in-the-air solution is quite well known from various existing applications for two-dimensional interfaces, combined under the description term multi-touch-interfaces.

The user is able to grab points in the world and to drag or rotate them just as he would in reality. Grabbing with two hands gives the user the ability to scale the world by changing the distance of his hands to each other - similar to resizing a window on your desktop. Contrary to most other navigation approaches, the user's impression is, that he, himself is standing still, while he moves the world around him.

For an implementation, tracking for two hands is needed, if tracking-devices deliver full matrix-values (instead of only positions), in theory, a more realistic way of computing the resulting transform is possible.

As the original navigation metaphor is well defined (grabbed points remain on their positions in world-space, but not in user-space), there was not much room for our own ideas to implement.

Since the implementation is quite general (the interface mainly consists from two input-matrices and to boolean-values for grabbing or not grabbing), it is easy to use different hardware. However, there are two existing implementations, on using WiiMotes and ART-Trackers (grabbing with the A-Button) and one using ARTPro-gloves. Both have advantages and disadvantages, the WiiMotes are easy to use for everyone and don't need calibration, the ARTPro-gloves provide better immersion.