Impact of Coordinate Systems on 3D Manipulations in Mobile Augmented Reality

Mobile touch PCs allow interactions with virtual objects in augmented reality scenes. Manipulations of 3D objects are a common way of such interactions, which can be performed in three different coordinate systems: the camera-, object- and world coordinate systems. The camera coordinate system changes continuously in augmented reality as it depends on the mobile device's pose. The axis orientations of the world coordinate system are steady, whereas the axes of the object coordinates base on previous manipulations. The selection of a coordinate system therefore influences the 3D transformation's orientation independent from the used manipulation type. In this paper, we evaluate the impact of the three possible coordinate systems on rotation and on translation of a 3D item in an augmented reality scenario. A study with 36 participants determines the best coordinates for translation and rotation.