Using Velocity Control to Navigate 3D Graphical Environments: A Comarison of three Interfaces

Abstract

Three velocity control interfaces to three dimensional virtual environments are compared. The interface devices are: a six degree of freedom position sensor, a six degree of freedom isometric joystick, and a conventional mouse in conjunction with a soft control panel displayed on the monitor. In each interface the devices are used to control velocity, and all make use of a quadratic function to map the input to the viewpoint velocity. We use two structured exploration tasks to assess the usability of the different interfaces. In the first task an interviewing technique is used in conjunction with an exploration task which involved examining widely spaced details of the 3D scene. The second task is designed to reveal how well users can interact at different scales using the different devices. Subjects are required to navigate through a tube which varies over four orders of magnitude in size. The results show that subject's behavior is highly constrained by the local size of the tube: they maintained a constant velocity relative to the local size of the tube. They also showed differences in the effectiveness of the different devices in determining traversal rate that the positioning device and the control panel were about equally effective for fast navigation, and both are better than the isometric joystick.