Computer Science 455

Instructor: R. P. Burton

Fourth Quiz

February 28-March 1, 2005

Name _________________________________________ Score ____________/27

1. Which of the following represents an unrecoverable situation?

   1. posted and painted

   2. posted but not painted

   3. painted but not posted

   4. neither posted nor painted

   5. (none represents an unrecoverable situation)

(e)

2. After a graphics structure has been created and closed,

   1. generally it is possible to open it for the purpose of adding graphics elements, without needing to relocate it

   2. generally it is possible to open it for the purposes of adding graphics elements, but this necessitates a relocation

   3. it cannot be changed

(b)

3. If several basic shapes are defined in master coordinates, the hierarchy that represents the contents of world coordinate space is a

   1. tree

   2. graph

(b)

4. The ratio of basic shapes to total nodes is probably greater in a relatively ____ hierarchy.

   1. flat

   2. tall

(a)

5. Where does the geometry reside in the hierarchy of the previous questions?

   1. in the root

   2. in the internal nodes including the root

   3. in the internal nodes excluding the root

   4. in the “leaves”

(d)

6. If the root is called world coordinates and the “leaves” are called master coordinates, what are (at least some of) the intermediate levels called?

   1. normal coordinates

   2. transformation coordinates

   3. master coordinates

(c)

7. Of the following, which is the least efficient (or the impossible) place to clip?

   1. screen coordinates

   2. world coordinates

   3. master coordinates

(b)

8. Clipping cannot be done in master coordinates because all objects are defined relative to the “origin,” and it is difficult if not impossible to select one object without getting at least parts of other objects.

   1. true

   2. false

(b)

9. Pick the best statement relative to GUIs.

   1. Like other kinds of graphics, the GUI should be attractive, even “eye catching,” and should incorporate graphics techniques to achieve this objective.

   2. A GUI should draw the user into the application, becoming almost transparent to the user.

   3. A GUI should be made to run as efficiently as possible, even at the expense of the objectives of choices (a) and (b).

(b)

10. A gravity field associated with a line segment probably has the shape of a(n)

    1. rectangle

    2. elongated oval

    3. dumbbell

(c)

11. All of the following are suitable for rubberbanding except

    1. drawing using XOR

    2. a “save, draw, restore” cycle

    3. drawing using a priority plane

    4. erasing using the complement of the drawing color

    5. (all are suitable)

(d)

12. All of the following are appropriate for selecting an element of a scene (where elements may overlap) except

    1. bounding boxes

    2. hot points

    3. cycling through candidates, guessing the level

    4. simply clicking on the element

    5. (no exceptions here)

(d)

13. Understanding the concepts required to recognize characters made of strokes sufficient to produce a working program likely would require _____ of reading or lecture time for a CS455 student.

    1. a half-hour

    2. a week

    3. 3 weeks

    4. 3 months

(a)

14. A collection of graphics elements (sometimes called a segment) probably should be

    1. elements which will be replicated as a group

    2. elements which will move as a group

    3. both (a) and (b)

    4. either (a) or (b)

(d)

15. An automobile designer moves his hands through the air to indicate the shape of a potential future automobile. The movement of his hands is traced by a computerized system. The designer is engaged in a(n) ____________ activity.

    1. analytic

    2. synthetic

(b)

16. Early versions of the mouse, such as the SRI mouse, were unsuitable for input because the wheels on the bottom of the mouse often slid along the surface instead of rotating as intended.

    1. true

    2. false

(b)

17. Suppose you have a tablet with 1000 wires running top to bottom and 1000 wires running left to right. What is the minimum number of bits needed to distinguish one wire from all the other wires?

    1. 1

    2. 10

    3. 20

(a)

18. Two perpendicular strip microphones and a knowledge of the plane containing the strip microphones determines _________.

    1. a unique point

    2. two points

    3. a line of points

    4. two lines of points

(b)

19. ____ point microphones must be mounted on a planar surface (such as a wall) in order to determine positions in 3D space.

    1. two

    2. three

    3. four

    4. more than four

(b)

20. The image drawn on a Direct View Storage Tube typically changed _______.

    1. 60 times/second or faster

    2. 30 times/second

    3. 15 times/second

    4. once/second

    5. once every several seconds, or even less frequently

(e)

21. How many different voltage levels could be expect to be sent to a cell of a plasma panel during an arbitrary session?

    1. one

    2. two

    3. three

    4. up to 1000

(c – write, erase, sustain)

22. Equipment can be added to an ordinary TV to create the depth effect experienced in a 3D movie.

    1. true

    2. false

(a)

23. The basis of touch panels is

    1. optical

    2. acoustical

    3. electrical

    4. (any of the above)

(d)

24. The ultimate graphics system is a voice-driven graphics system, but it’s still a ways off.

    1. true

    2. false

(b)

25. Pick the best statement.

    1. the relationship between the logical devices and the physical devices is 1:1

    2. the relationship between the logical devices and the physical devices is 1:many

    3. the relationship between the logical devices and the physical devices is many:1

    4. virtually any physical device can function as any of the logical devices

(d)

26. Call them what you will, all coordinate systems used for computer graphics are Cartesian.

    1. true

    2. false

(b)

27. There is no such thing as a true 3D output device. 2.5D yes, but not 3D.

    1. true

    2. false

(b)