A Quick Algorithm for Snapping 3D Objects in Augmented Reality

This paper describes a quick algorithm for snapping a moving object (being moved by a user) to existing objects in Augmented Reality (AR) environment. Because in AR, human-computer interactions are in the real time mode, the algorithm should be fast enough not to affect the scene rendering but still assure accuracy. It is currently designed to deal with primitive geometries such as cubes, cones, cylinders, spheres. And it should work well even after these geometries are transformed with scaling, rotating, moving operations. The main idea of the algorithm is that for each kind of geometry, some ldquohot spotsrdquo are defined. Each hot spot is a sphere with a certain radius. If the center point of the moving object is within a hot spot of any existing geometry it will be snapped to this geometry at that hot spot. This algorithm is already employed in an AR modeling system to evaluate its efficiency.