An Augmented Reality (AR) CAD System at Construction Sites

Augmented Reality (AR) technologies allow computer-generated content to be superimposed over a live camera view of the real world. Although AR is still a very promising technology, currently only a few commercial applications for industrial purposes exploit the potential of adding contextual content to real scenarios. Most of AR applications are oriented to fields such as education or entertainment, where the requirements in terms of repeatability, fault tolerance, reliability and safety are low. Different visualization devices, tracking methods and interaction techniques are described in the literature, establishing a classification between Indoor and Outdoor AR systems. On the one hand, the most common AR developments correspond to Indoor AR systems where environment conditions can be easily controlled. In these systems, AR applications have been oriented traditionally to the visualization of 3D models using markers. On the other hand, outdoor AR developments must face additional difficulties such as the variation on lighting conditions, moving or new objects within the scene, large scale tracking, etc... which hinder the development of new systems in real scenarios.