Chapter 7: Direct Manipulation and Immersive
Environments
Discussion Topics with Answers
1. Describe three principles of direct manipulation.
a) Continuous representations of the objects and actions of interest with
2. Give four benefits of direct manipulation. Also list four problems of direct
manipulation.
Benefits:
a) Control/display compatibility
3. Examining the success of video games can provide insight for interface designers.
Explain what lessons can be learned by videogames for interface design, but also
provide examples of areas where it is ineffective to do so.
The physical actions—such as button presses, joystick motions, or knob rotations—
produce rapid responses on the screen. There is no syntax to remember, and
4. An airline company is designing a new on-line reservation system. They want to
add some direct-manipulation features. For example, they would like customers to
click a map to specify the departure cities and the destinations, and to click on the
calendar to indicate their schedules. From your point of view, list four benefits and
four problems of the new idea compared with their old system, which required the
customer to do the job by typing text.
Benefits:
a) Learning time probably reduced, but we would need usability study to
verify, particularly for novice users.
5. List a few guidelines for an effective 3D interface:
a) Provide overviews so users can see the big picture
b) Allow teleoperation
c) Offer X-ray vision so users can see into or beyond objects
6. List an example of teleoperation or virtual reality. Consider what a future
application (that does not presently exist) might do — be creative!
• An example is telemedicine (e.g. used for remote diagnosis, see DTUI6 Fig.
7.9)