Quiznetik

CAD-CAM and Automation | Set 1

1. Which coordinate system is a device-dependent coordinate system?

Correct : D. Screen Coordinate System

2. Which of the following is the default coordinate system?

Correct : B. World Coordinate System

3. When every entity of a geometric model remains parallel to its initial position, the transformation is called as

Correct : B. World Coordinate System

4. In which type of projection, actual dimensions and angles of objects and therefore shapes cannot be preserved?

Correct : B. World Coordinate System

5. The matrix representation for translation in homogeneous coordinates is

Correct : B. World Coordinate System

6. The matrix representation for scaling in homogeneous coordinates is

Correct : A. P’=S*P

7. The two-dimensional rotation equation in the matrix form is

Correct : C. P’=R*P

8. What is the use of homogeneous coordinates and matrix representation?

Correct : A. To treat all 3 transformations in a consistent way

9. If point are expressed in homogeneous coordinates then the pair of (x, y) is represented as

Correct : D. (x’, y’, w)

10. For 2D transformation the value of third coordinate i.e. w (or h) =?

Correct : A. 1

11. We can combine the multiplicative and translational terms for 2D into a single matrix representation by expanding

Correct : B. 2 x 2 matrix into 3 x 3

12. The general homogeneous coordinate representation can also be written as

Correct : B. (h.x, h.y, h)

13. In homogeneous coordinates value of ‘h’ is consider as 1 & it is called…..

Correct : D. Non-Zero Scalar Factor

14. Which co-ordinates allow common vector operations such as translation, rotation, scaling and perspective projection to be represented as a matrix by which the vector is multiplied?

Correct : D. homogenous co-ordinates

15. In Coordinates, a points in n-dimensional space is represent by (n+1) coordinates.

Correct : B. Homogeneous

16. A translation is applied to an object by D

Correct : A. Repositioning it along with straight line path

17. We translate a two-dimensional point by adding

Correct : D. Only a

18. The translation distances (dx, dy) is called as

Correct : C. Both a and b

19. In 2D-translation, a point (x, y) can move to the new position (x’, y’) by using the equation

Correct : B. x’=x+dx and y’=y+dy

20. The two-dimensional translation equation in the matrix form is

Correct : A. P’=P+T

21. -------is a rigid body transformation that moves objects without deformation.

Correct : C. Translation

22. A straight line segment is translated by applying the transformation equation

Correct : A. P’=P+T

23. Polygons are translated by adding to the coordinate position of each vertex and the current attribute setting.

Correct : D. Only b

24. To change the position of a circle or ellipse we translate

Correct : B. Center coordinates and redraw the figure in new location

25. The basic geometric transformations are

Correct : D. All of the mentioned

26. A two dimensional rotation is applied to an object by

Correct : C. Only b

27. To generate a rotation , we must specify

Correct : A. Rotation angle θ

28. The rotation axis that is perpendicular to the xy plane and passes through the pivot point is known as

Correct : A. Rotation

29. Positive values for the rotation angle θ defines

Correct : C. Counter clockwise rotations about the pivot point

30. The original coordinates of the point in polar coordinates are

Correct : B. X’=r cos (Ф +ϴ) and Y’=r sin (Ф +ϴ)

31. From the following, which one will require 4 matrices to multiply to get the final position?

Correct : B. Rotation about an arbitrary Point

32. Rotation is simply---------object w.r.t origin or centre point.

Correct : A. Turn

33. A line AB with end point A (2,3) & B (7,8) is to be rotated about origin by 300 in clockwise direction. Determine the coordinates of end points S of rotated line.

Correct : D. (3.232, 1.598)

34. An ellipse can also be rotated about its center coordinates by rotating

Correct : B. Major and minor axes

35. The transformation that is used to alter the size of an object is

Correct : A. Scaling

36. Scaling of a polygon is done by computing

Correct : D. Only a

37. We control the location of a scaled object by choosing the position is known as…………………………….

Correct : B. Fixed point

38. If the scaling factors values sx and sy are assigned to the same value then………

Correct : B. Uniform scaling is produced

39. If the scaling factors values Sx and Sy are assigned to unequal values then

Correct : C. Differential scaling is produced

40. The objects transformed using the equation P’=S*P should be

Correct : C. Both a and b

41. If the scaling factors values Sx and Sy < 1 then

Correct : A. It reduces the size of object

42. If the value of Sx=1 and Sy=1 then

Correct : D. No change in the size of an object

43. The polygons are scaled by applying the following transformation.

Correct : A. X’=x * Sx + Xf(1-Sx) & Y’=y * Sy + Yf(1-Sy)

44. Reflection is a special case of rotation.

Correct : B. False

45. If two pure reflections about a line passing through the origin are applied successively the result is

Correct : A. Pure rotation

46. What is the determinant of the pure reflection matrix?

Correct : C. -1

47. Which of the following is NOT true? Image formed by reflection through a plane mirror is

Correct : B. same orientation

48. Which of the following represents shearing?

Correct : D. (x, y) → (x+shy, y+shx)

49. If a ‘3 x 3’ matrix shears in X direction, how many elements of it are ‘1’?

Correct : B. 3

50. If a ‘3 x 3’ matrix shears in Y direction, how many elements of it are ‘0’?

Correct : D. 5

51. Shearing is also termed as

Correct : D. Skewing

52. Shearing and reflection are types of translation.

Correct : B. False

53. Which of this is compulsory for 2D reflection?

Correct : C. Reflection axis

54. Two successive translations are

Correct : D. Additive

55. Two successive translations are commutative.

Correct : A. True

56. General pivot point rotation can be expressed as

Correct : B. T(xr,yr).R(θ).T(-xr,-yr) = R(xr,yr,θ)

57. Which of the following is NOT correct (A, B and C are matrices)

Correct : A. A∙B = B∙A

58. Reflection about the line y=0, the axis, is accomplished with the transformation matrix with how many elements as ‘0’?

Correct : D. 6

59. Which transformation distorts the shape of an object such that the transformed shape appears as if the object were composed of internal layers that had been caused to slide over each other?

Correct : D. Shearing

60. Transpose of a column matrix is

Correct : C. Row matrix

61. Reversing the order in which a sequence of transformations is performed may affect the transformed position of an object.

Correct : A. True

62. How many minimum numbers of zeros are there in ‘3 x 3’ triangular matrix?

Correct : B. 3

63. The object space or the space in which the application model is defined is called

Correct : A. World co-ordinate system

64. What is the name of the space in which the image is displayed?

Correct : B. Screen co-ordinate system

65. What is the rectangle in the world defining the region that is to be displayed?

Correct : C. World window

66. The window opened on the raster graphics screen in which the image will be displayed is called

Correct : D. Interface window

67. The process of mapping a world window in World Coordinates to the Viewport is called Viewing transformation.

Correct : A. True

68. Panning is a technique in which users can change the size of the area to be viewed in order to see more detail or less detail.

Correct : B. False

69. Drawing of number of copies of the same image in rows and columns across the interface window so that they cover the entire window is called

Correct : D. Tiling

70. By changing the dimensions of the viewport, the and of the objects being displayed can be manipulated.

Correct : C. Size and proportions

71. Co-ordinates are ranging according to the screen resolution.

Correct : A. True

72. Any convenient co-ordinate system or Cartesian co-ordinates which can be used to define the picture is called

Correct : D. world co-ordinates

73. The transformation of perspective projection must include, where d is the distance between the center of projection to the projection plane.

Correct : D. -1/d

74. An area on a display device to which a window is mapped is called a………….

Correct : B. Viewpoint

75. A Pixel is

Correct : C. The smallest resolvable part of a picture

76. A system that automates the drafting process with interactive computer graphics is called

Correct : B. Computer Aided Design (CAD)

77. In which type of projection, actual dimensions and angles of objects and therefore shapes cannot be preserved?

Correct : C. Perspective

78. Coordinate of □ABCD is WCS are: lowermost corner A(2,2) & diagonal corner are C(8,6). W.r.t MCS. The coordinates of origin of WCS system are (5,4). If the axes of WCS are at 600 in CCW w.r.t. the axes of MCS. Find new vertices of point A in MCS.

Correct : A. (4.268, 6.732)

79. A line AB with end points A (2, 1) & B (7, 6) is to be moved by 3 units in x-direction & 4 units in y-direction. Calculate new coordinates of points B.

Correct : C. (10, 10)

80. QFor generating Coons patch we require

Correct : C. Four bounding curves defining surface

81. In a 2-D CAD package, clockwise circular arc of radius, 5, specified from P1 (15,10) to P2 (10,15)will have its center at

Correct : A. (10, 10)

82. In the following geometric modelling techniques which are not three-dimensional modelling?

Correct : B. Drafting

83. In the following three-dimensional modelling techniques. Which do not require much computer time and memory?

Correct : C. Wireframe modelling

84. In the following geometric modelling techniques. which cannot be used for finite element analysis:

Correct : D. none of the above

85. In the following geometric primitives. which is not a solid entity of CSG modelling:

Correct : D. Circle

86. Which of the following is not an analytical entity?

Correct : C. Spline

87. Which of the following is not a synthetic entity?

Correct : A. Hyperbola

88. Which one of the following does not belong to the family of conics?

Correct : D. Line

89. The number of tangents required to describe cubic splines is

Correct : B. 1

90. The shape of Bezier curve is controlled by

Correct : A. Control points

91. The curve that follows a convex hull property is:

Correct : B. B-spline

92. The degree of the Bezier curve with n control points is

Correct : A. n + 1

93. The degree of the B-spline with varying knot vectors

Correct : A. Increases with knot vectors

94. The number of non-coincidental points required to define the simplest surface are

Correct : B. 3

95. The tensor product technique constraints surfaces by two curves.

Correct : B. 1

96. In the bezier curve, the curve is always to first and last segments of the polygon

Correct : C. tangent

97. The unit vector in the direction of the line is defined as .

Correct : C. tangent vector/length of the line

98. From the following, which is an axisymmetric surface?

Correct : C. Surface of Revolution

99. curves allow local control of the curve

Correct : D. B-Spline

100. To determine the coefficients of the equation – two end-points and the two tangent vectors. This statement is true for which of the following

Correct : B. Hermite Cubic Spline Curve