Computer Science 455
Instructor: R. P. Burton
Fifth Quiz
June 1-2, 2004
Name _________________________________________ Score ____________/44
1. Curves typically are clipped by using
a. one of the point or line clipping algorithms
b. the Catmull-Rom algorithm
c. the Parke-Cannon algorithm
(a)
2. The clipping algorithms can be adapted to blanking with the exception of
a. Cohen Sutherland
b. Liang & Barsky
c. Nicholl Lee Nicholl
d. Sutherland Hodgman
e. Weiler Athertton
f. (no exceptions here)
(f)
3. If you are attempting to produce a representation of Mt. Timpanogos, you are engaged in a(n) ____________ graphics activity.
a. analytic
b. synthetic
(a)
4. As discussed in class _______ determination of object descriptions typically is more difficult than _______ determination of object descriptions.
a. analytic, synthetic
b. synthetic, analytic
(a)
5. Graphics software always deals in Cartesian coordinates – sometimes left-handed and sometimes right-handed.
a. true
b. false
(b)
6. Everyone sees darker (on a light background) or thicker lines as
a. closer
b. farther away
c. (neither (a) nor (b) always holds)
(c)
7. If a graphics element is “hidden,” it is not presented or drawn in any way.
a. true
b. false
(b)
8. Transformations of the kinds discussed in class have a direct effect on the ____ of objects.
a. geometry
b. topology
c. geometry and topology
d. geometry, topology, and other attributes
(a)
9. The planar equation Ax + By + Cz + D = 0 is a(n) ______ equation.
a. explicit
b. implicit
c. parametric
(b)
10. Suppose you have a transformation M which can be used to transform the coordinates of the vertices of a polygon which lies in a plane. What is the transformation which correspondingly transforms the planar coefficients A, B, C, and D?
a. M
b. M inverse
c. M transpose
d. (none of the above)
(b)
11. What are superquadrics?
a. higher-dimensional quadric surfaces
b. compound quadric surfaces
c. quadric surfaces with additional parameters for adjusting shapes
(c)
12. Blobby objects are most likely to maintain _______.
a. shape
b. volume
c. center of mass
d. no apparent vertices
(b)
13. The size of a projection is impacted by the object’s distance from the display surface, if it is a ________ projection.
a. parallel
b. perspective
c. either a parallel or perspective
d. orthographic
e. oblique
f. either orthographic or oblique
(b)
14. Which of the following is not a plausible projection?
a. parallel perspective
b. parallel oblique
c. parallel orthographic
d. perspective oblique
e. (all are plausible)
(a)
15. Which of the following projections is most likely to reveal information about x, y, and z “uniformly?”
a. parallel perspective
b. axonometric
c. isometric
d. cavalier
e. cabinet
(c)
16. Which of the following projections is more accurate for purposes of measurement?
a. cavalier
b. cabinet
(a)
17. A perspective projection of a vertex is a division by
a. the z-value of the vertex
b. the distance to the vertex
c. the square of the z-value of the vertex
d. the square of the distance to the vertex
(a)
18. A polyhedron has at most ____ vanishing point(s).
a. one
b. two
c. three
d. more than three
(d)
19. What is the purpose of a view volume?
a. to facilitate viewing coordinates and the viewing transformation
b. to select a portion of the world to be viewed
c. to transform so that all projections are parallel orthographic projections
(b)
20. Parallel orthographic projection can be as simple as dropping the z coordinate.
a. true
b. false
(a)
21. All of the following can be transformed for parallel orthographic projection EXCEPT
a. perspective orthographic
b. perspective oblique
c. parallel oblique
d. (no exceptions here)
(d)
22. The image of the viewport ______ be mapped to master coordinates for clipping purposes.
a. can
b. cannot
(a)
23. All of the following can be extended to 3D EXCEPT
a. Cohen Sutherland
b. Liang Barsky
c. Sutherland Hodgman
d. Weiler Atherton
e. (no exceptions here)
(e)
24. If two curves meet at a common endpoint, and both curves have the same first derivative at that common endpoint, the curves manifest _______ continuity at that common endpoint.
a. no
b. zero-order
c. first-order
d. second-order
e. total
(c)
25. All things considered, it is usually better to work with curves that _________ control points.
a. approximate
b. interpolate
c. are unresponsive to
(a)
26. For a Bezier curve, each control point in a collection of control points has its own blending function.
a. true
b. false
(a)
27. Given ten different Bezier curves each determined by five control points, it is _____ ten curves.
a. possible that no blending functions will be common to any of the
b. certain that no blending functions will be common to any of the
c. certain that five blending functions will suffice for all
(c)
28. What does the “convex hull” property guarantee in 2D?
a. that a curve can be inscribed within a convex polygon
b. that the curve is concave
c. that the curve does not self-intersect
(a)
29. Bezier curves
a. cannot be closed
b. always pass through the endpoints
c. always pass through all the control points
d. (all of the above)
e. (none of the above)
(b)
30. If two Bezier curves are joined, continuity at the endpoint ____ be controlled.
a. can
b. cannot
(a)
31. Which of the following is NOT characteristic of B-spline curves?
a. global control
b. local control
c. lower order polynomials
d. (all are advantages of B-spline curves)
(a)
32. A section through a Bezier surface is a Bezier curve
a. independent of how the section is chosen
b. only if the section is parallel to an edge
c. only if the section is coincident with an edge
d. (none of the above)
(c)
33. Bezier and B-spline techniques are applicable to
a. curves and surfaces
b. volumes, curves, and surfaces
c. hypervolumes, volumes, curves, and surfaces
(c)
34. Suppose a quadrilateral is swept translationally by several hundred units to produce a “rod.” How many polygons should result from the sweep?
a. not more than 15
b. more than 15, but less than 100
c. 100 or more, but not more than 1000
d. 1000 or more
(a)
35. The path along which a shape is swept can be determined by all of the following EXCEPT
a. translation
b. rotation
c. scaling
d. a Bezier or B-spline
e. (no exceptions here)
(c)
36. During a sweep, a shape may be subjected to all of the following EXCEPT
a. rotation
b. scaling
c. shearing
d. reflection
e. (no exceptions here)
(e)
37. For purposes of constructive solid geometry, basic shapes may be
a. unioned
b. intersected
c. differenced
d. (all of the above)
(d)
38. An octree is
a. a highly efficient means of representing polyhedral shells which capitalizes on base 2 machine representation
b. a technique for representing solid objects
c. a three-dimensional binary partitioning technique which groups objects according to their fundamental shapes for subsequent rendering of the common shape
(b)
39. The octants in an octree are
a. all of a uniform size
b. of varying sizes all related by powers of 2
c. of varying sizes, but not limited to “powers of 2” relationships
(b)
40. An octant _____ be void.
a. can
b. can never
(a)
41. Removal of hidden elements (or determination of visible elements) should be done _________ transformation from world coordinates to viewing coordinates.
a. before
b. after
(b)
42. What is the minimum dimensionality of a ‘hider” in 7-dimensional space.
a. 2
b. 3
c. 6
d. 7
e. 8
(c - 6)
43. The Roberts’ hidden-line algorithm solves the hidden-line problem
a. at each pixel
b. in the 3-dimensional space in which the objects reside
c. in a higher-dimensional space to which the objects are mapped
(b)
44. When random midpoint displacement is done to produce a fractal forgery, all of the following are true EXCEPT
a. the average displacement should be zero
b. the displacement is proportional to the length of the associated edge
c. the average displacement occurs at the middle of the edge
d. the likelihood of a point being chosen for displacement is proportional to its proximity to the middle of the edge
e. (no exceptions here)
(e)