This chapter presents a series of new augmented reality user interaction techniques to support the capture and creation of 3D geometry of large outdoor structures. Named construction at a distance, these techniques are based on the action at a distance concepts employed by other virtual environments researchers. These techniques address the problem of AR systems traditionally being consumers of information, rather than being used to create new content. By using information about the user’s physical presence along with hand and head gestures, AR systems can be used to capture and create the geometry of objects that are orders of magnitude larger than the user, with no prior information or assistance. While existing scanning techniques can only be used to capture existing physical objects, construction at a distance also allows the creation of new models that exist only in the mind of the user. Using a single AR interface, users can enter geometry and verify its accuracy in real-time. Construction at a distance is a collection of 3D modelling techniques based on the concept of AR working planes, landmark alignment, constructive solid geometry operations, and iterative refinement to form complex shapes. This chapter presents a number of different construction at a distance techniques, and are demonstrated with examples of real objects that have been modelled in the physical world.
Image Based Shadowing in Real-Time Augmented Reality
