Reality for Free
AR mixes real and virtual objects. As opposed to purely virtual experiences, augmented experiences can be richer and more elaborate because of the deliberate inclusion of real-world objects and behaviors. We can separate this advantage into three distinct elements:
- Content. Because the real world is used directly, the AR environment is vast and detailed. A purely virtual experience suffers from a confining bottleneck of content creation.
- Behavior. Rich real-world behaviors, such as the laws of physics, are included without effort. In a purely virtual environment, these would need to be simulated by code.
- Multiple Senses. Interfaces to purely virtual worlds are typically limited to vision and sound, perhaps with modest haptic feedback; the real world provides a wide array of sensory experiences, including taste, smell, and ambiance such as temperature and humidity.
The counterpart to the advantages accruing from the use of reality is the flexibility afforded by the use of digital artifacts. Their appearance and behavior are governed by code, and hence can be altered according to the needs of the user or application. The following are two of the most prominent applications of this flexibility:
- Customization. Virtual artifacts can be personalized according to user preferences; for example, attributes such as language or color can be adjusted.
- Impossibility. Virtual content can depict objects and processes that are impractical or impossible to bring to users otherwise, for instance because they don't exist in the real world, would take too long to observe in real time, or would be dangerous to experience directly.
AR users retain their ability to move freely and the interface does not interfere with their ability to observe their real-world environment. They are able to switch attention seamlessly between real and virtual objects; in some cases (such as descriptive markup) the user may not care whether an object is real or virtual. We want to particularly emphasize two aspects of the invisible interface:
- Natural movement. User input can take the form of familiar real-world actions; direct manipulation and gesture based interaction are possible.
- Single focus. When augmentations are aligned with the task at hand, focus can stay in one place. Users do not, for example, have to change their focus from their task to a paper manual opened beside them.
Some of AR's advantages owe their existence to a clear connection between real and virtual objects, including larger-scale entities such as physical locations. We distinguish two advantages relating to the physical context in which augmentations are embedded:
- Adjust to surroundings. Virtual content automatically updates as the user's surroundings change; change can either be a change in the world (such as the movement of a real-world object or a change in temperature) or reflect a change in the user's position or viewpoint.
- Align spatially. Close matching of real objects with virtual markup makes associations obvious. For virtual objects which may not have a real analog, opportunistic matching to real objects can lend physicality. For example, labels aligned to a particular object are clearly meant to give information about that object as a real label would.
Paper content copyright by AACE. Reprinted from the Proceedings of World Conference on E-Learning in Corporate, Government, Healthcare, and Higher Education 2012 with permission of AACE (http://www.aace.org).