Recent developments in Augmented Reality (AR) technology are opening up new ways of representation and interaction with virtual objects; at the same time, increase in processing power of portable devices is enabling a wide diffusion of applications until recently usable only in very specific situations (like motion-capture labs).

LINEAR (Live-generated Interface and Notation in Augmented Reality) is an environment designed for musical performance in AR. One performer, using an AR iPhone app, can create virtual objects (rendered in real-time and superimposed to the real environment) according to the movement of the device; they are used both as virtual interfaces for electronics (sending OSC message to Max/MSP on a computer) and as live-generated graphic notation. LINEAR allows, with some limitations, the representation of gestural movements with an exact 3-D placement in space: we can now have an analogic notation of gestures, rather than a symbolic one. For the iPhone performer, the act of notation corresponds to the notated act.

The resulting representations can be also interpreted as a form of graphic animated notation by other performers (the iPhone screen is mirrored to a projector). The multiperspectivity of the notation and the possibilities of interaction with virtual bodies allow a high level of flexibility and foresee a potentially very rich scenario.