Computer Graphics u and i Star

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JNTU ONLINE EXAMINATIONS [Mid 2 - Computer Graphics]

1. The surfaces generated by cubic polynomials in both u and v parameters are called asa. Quadricb. Bi-Quadricc. Cubicd. Bi-cubic

2. Which of the following is not one of the polygon - mesh representationa. Explicit representationb. Pointers to a vertex listc. Pointers to an edge listd. Pointers to a polygon list

3. If are points on a plane, then the plane's normal is computed as

a.

b.c.

d.

4. Howmany polynomials in a parameter 't' are to be defined for identifying a point on a 3-D curvea. Oneb. Twoc. Threed. Number depends on complexity

5. The surfaces which are defined implicitly by an equation are called asa. Cubic surfaceb. bi-cubic surfacec. Quadric surfacesd. Binomial surfaces

6. Which of the following is not a common representation of 3D surfacea. Polygan mesh surfaceb. Parameteric surfacec. Quadric surfaced. Neural surface

7. Which of the following is not a characterstic of parametric curvesa. Simpleb. Possible to generalizec. Possible to identify any number of intermediate pointsd. Huge data base of intermediate points need to be explicitly stored

8. A set of connected polygonally bounded planar surfaces is called asa. Polygan meshb. Sol id objectc. 3-D objectd. mesh-cube

9. A polynomial curve using a parameter t is called asa. Parametric polynomial curveb. Cubic polynomial curvec. Quatric polynomical curved. Solid polynomial curve

0. The polynomial with maximum power 3, is called asa. Cubic polynomialb. Quadric polynomialc. Binomial polynomiald. Acute polynomial

1. Which of the following is not a reason for using cubic polynomials in parametric forma. It gives sufficient flexibilityb. does not introduce unwanted wigglesc. Polyonomials of degree 4 and above involve more computationsd. It is not possible to generate curves and surfaces with other kinds of polynomials

2. Which of the following is true about G1 (Geometric continuty) and C1 (Parametric first degree continuty)

a. C1 continuty implies G1

b. G1 continuty is generally more restrictive than is C1

c. C1 and G1 are identical

d. G1 continuity imples C1

3. Which of the following parametric curves are lowest-degree non-planar curves in 3D

a. Cubicb. Quadraticc. Curves with degree 4d. Curves with degree n

4. If the directions of two segments' tangent vectors are equal at a joining point, the curve is said to have _ _ _ _ _ _ _ _ _ geometric continuety

a. G0

b. G1

c. G2

d. Gn

5. In the case of curve joining, G1 geometriccontinuty meansa. Only geometric points are sameb. The geometic slopes of the segments are samec. The geometric slopes and lengths of the segments are samed. The geometric slopes are different but the lengths of the segments are same

6. If the direction and magnitude of through the derivative are equal at the joining point, the curve is called _ _ _ _ _ _ _ _ continuous

a. C0 b. C1

c. C2

d. Cn

7. For two curves to join smoothly, the essential requirement isa. Their tangent - vector directions must matchb. Their magnitudes must matchc. Both their tangent vector directions and magnitudes must matchd. either tangent vector directions or magnitudes must match

8. Howmany coefficients are there in a cubic polynomiala. 3

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b. 4c. any numberd. 1

9. To deal with finite segments of the curve, without loss of generality, we resptrict the parameter t, to _ _ _ _ _ _ intervala.

b.

c.

d.

0. If Q(t) is a cubic polynomial, then the tangent vector of the curve is

a. [Q(t)]2 b. Q'(t)c. 1/Q(t)d.

1. The basis matrix for Hermites curve is

a.

b.

c.

d.

2. The property that the curves can be transformed by transforming the geometric vectors and then using it to generate the transformed curvemakes the Hermites curvesa. Invariant under only rotationb. Invariant under only scalingc. Invariant under only translationd. Invariant under rotation, scaling and translation

3. Out of the four blending functions of Hermites, howmany are non-zero at t=0a. 1b. 2c. 3d. 4

4. For two Hermite cubics to share a common end point with G1 geometrical continuty, which of the following conditions must be satisfieda. The magnutudes of the vectors must be sameb. The tangents at the end points must be samec. Both the magnutuedes and tangents must be samed. Both must have order continuty

5. The Horner's rule for factoring polynomial f(t) = is

a.

b.

c.

d.

6. The Hermite curves are not invariant undera. rotationb. scalingc. translationd. perspective projection

7. Which of the following require, for its definition, two end-points and two end-point tangent vectorsa. Hermite curveb. Bezier curvec. B-splined. -spline

8. If M is a basis matrix and G is a matrix representing a vector of geometric constraints, then the Hermite's coefficent vector matrix is defined as

a. C=M.Gb. C=M+Gc. C=M

d. C=M-G

9. The Hermite form of the cubic polynomial curve segment is determined bya. Any four control pointsb. Either four control points or four tangentsc. Two end-points and the tangents at two end-pointsd. Two end-points and any other two intermediate points

0. The cubic curves are _ _ _ _ _ _ _ _ _ combinations of the four elements of the geometry vectorsa. linearb. non-linearc. complexd. higher-degree

1. The Bazier basis matrix MB

is defined as

a.

b.

c.



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d.

2. The general equation for Bernestein polynomials is given bya. Q(t) =

b. Q(t) =

c. Q(t) =

d. Q(t) =

3. Which of the following is false about Bazier curvea. The blending functions are non negativeb. The blending function are sum to onec. The output curve is completely within the convex hulld. At t=0, all the Bernstein polynamials are zero

4. In the Bazier curve, the sum of all Bernstein polynomials at every point in the range of is

a. Unityb. Zeroc. n units if there n control pointsd. varies with position of control points

5. If the given four control points of Bazier curve forms a convex hull, the corresponding output curve isa. completely inside the convex hullb. completely outside the convex hullc. oscillates between outside and insided. not a function of control points

6. At the joining of two Bezier curves, G1 continuty is provided only ifa.

b.

c.

d.

7. If are four control points, in the same order, given as input for Bazier curve, then the curve passes trough

a. all four control pointsb. Only

c. Only

d. The control points influence, but curve does not pass through any control point

8. The property that the change of location of any control point will have influence on every point on the curve or surface is called asa. Global controlb. Local controlc. Generic controld. enfluence control

9. The range of parametric variable 't' used in Bazier curve isa.

b.

c.

d.

0. In uniform nonrational B-splines, the curve segment Q1

is defined in the parameter range of

a.

b.

c.

d.

1. In Uniform non-rational B-splines, the curve segment Q3

is defined in the parameter range of

a.

b.

c.

d.

2. If the B-spline curve is defined with m+1 control points, total number of curve segments in the B-spline curve isa. m-2b. m+1c. md. 1

3. Which of the following is not a feature of local controla. moving a control point effects only a part of a curveb. time needed to compute the coefficients is greatly reducedc. all cubic splines are chatacterised by local controld. knot values are defined in algorithms

4. In uniform B-splines, the term uniform meansa. Knots are spaced at equal intervalsb. Knots are spaced at two end points of the curvec. Knots are spaced at regular intervalsd. knots are spaced at steep curvatures

5. Which of the the following is not a characterstic of B-spline blending functionsa. Everywhere non negativeb. Sum to Unityc. The output curve is constraned to a convex hulld. Blending function is influenced by all m+1 control points

6. B-Splines consist of curve segments whose polynomial coefficents depend on just few control points. This property of B-Splines is called asa. global controlb. local controlc. generic controld. infinite control

7. If the parametric functions x(t),y(t) and z(t) each are defined as the ratio of two cubic polynomials, such splines are called asa. rat ionalb. semi rationalc. non-rationald. trivial

8. In the B-splines algorithm, the term B stands for



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a. basicb. basisc. base l ined. bicubic

9. According to phase specular - reflection model, as the specular parameter 'n's

increases, the sharpness of specular reflection

a. increasesb. decreasesc. remain unchanged. increase until n=256 and then decreases

0. The range of values for the reflection coeffients followed in illumination model isa. 1 to 2b. 0 to 1c. -1 to 1d. 0 to

1. The amount of incident light specularly reflected is depending on angle betweena. incident light ray and the surface normal

b. reflected light ray and the surface normalc. reflected light ray and the direction of view pointd. incident light ray and the direction of view point

2. At the sharp specular high-lights in Phong illumination model, what are the corresponding Ks

and n values where Ks

is specular reflection coefficent

and 'n' is an integer constant used in

a. Both Ks

and n are large values

b. Ks

is large and n is small value

c. Ks

is small and n is large value

d. both Ks

and n are small values

3. The light which is from a non-directional source of light, the product of multiple reflections from many sources of light is called asa. ambient lightb. self-luminous lightc. specular lightd. diffuse light

4. If the Ip is the point light source intensity, then the diffuse illumination equation is given bya. I =

b. I =

c. I =

d. I =

5. Specular reflections are observed ona. completely transperent objectsb. shiny surface objectsc. rough surface objectsd. course objects

6. Surfaces that are rough and grainy, tend to scatter the reflected light in all directions. This scattered light is calleda. Specular reflectionb. Diffuse reflectionc. Ambient reflectiond. Shiny reflection

7. Surfaces that are shiny and the light sources create highlights or bright spots calleda. specular reflection

b. distributed reflectionc. diffuse reflectiond. ambient reflection

8. To compute the final intensity at any arbitrary surface point, atmost howmany interpolations are to be performeda. 1b. 2c. 3d. 4

9. If the vertex V is surrounded by 'n' polygons and the surface normal of each of the surrounded polygon is Nk, then the unit vertex

normal Nv

at V is given by

a.

b.

c.

d.

0. Incremental calculations are used to obtain intensity values between scan lines and along scan lines. Reason for following this approach isa. It gives smooth intensitiesb. It gives pleasant intensitiesc. to make it frce mach-band effectd. to make it computationally efficient

1. The principle of Gouraud shading isa. vector interpolationb. intensity interpolationc. surface interpolationd. one intensity for one surface

2. The principle of constant intensity shading isa. vector interpolationb. interisity interpolationc. single intensity for complete polygond. surface interpolation

3. Which of the following draw back is observed in Gouraud shadinga. Mach bandsb. intensity discontinuities at the surface boardersc. Computationally very expensived. incremental calculations are not applicable

4. In Gourand shading, the Mach band effect is reduced or eliminated bya. dividing the surface into a greater number of polygon facesb. Using encremental calculationsc. entersity inter polationsd. computing the entensities along the scan lives

5. In which of the following algorithms, these steps are followed in the same sequance:1) determine average unit normal vector at each vertex



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c.

d.

4. A transformation system in which an object in created and described in coordinates with respect to its own and indipendent object coordinatedspace, and place an instance or copy of it within a larger scence, is called asa. geometric transformationb. coordinate transformationc. instance transformationd. complex transformation

5. If the axis of rotation is X, then the direction of positive rotation isa. y to zb. z to xc. x to y

d. y to x

6. If the axis of rotation is Y, then the directionof positive rotation isa. y to zb. z to xc. x to yd. y to x

7. In 3-D space rotation of an object is done abouta. a pointb. an axisc. a planed. a hyper plane

8. In 3-D space, the scaling is performed with respect toa. a reference pointb. a reference planec. a reference axisd. an hyper plane

9. In 3-D transformations, the two scalling operations are

a. alwalys commutativeb. always non- commutativec. commutative only if all scalling parameters of atleast one of the two scaling matrices are same.d. commutative only if all the scalling parameter of both the scalling matrices are same

0. In a 3-D scaling transformation, all the three scalling parametersa. must be positive and greater than oneb. must be positivec. either positive or negatived. must be a combination of positive and negative

1. let v is a vertex of an object p. When the scaling operation is applied on the object p with respect to vertex v, which of the following is truea. The cordinates of only vertex v are unchangedb. The coordinates of all vertices are unchangedc. The coordinates of vertices are changed in magnificationd. The coordinates of vertex v are unchanged only if all the scaling factors are same

2. If the axis of rotation is Z, then the directionof positive rotation isa. y to zb. z to x

c. x to yd. y to x

3. The three minesional matrix transformation for rotation with an angle with respect to z-axis in the negative direction is

a.

b.

c.

d.

4. The three dimensional matrix transformation for rotation with an angle with respect to y-axis is the negative direction is

a.

b.

c.

d.

5. The three dimensional matrix transformation for rotation with an angle with respect to x-axis in the positive direction is

a.



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b.

c.

d.

6. The three dimenesional matrix transformation for rotation with an angle with respect to z-axis in the positive direction is

a.

b.

c.

d.

7. The three dimensional matrix transformation for rotation with an angle with respect to y-axis in the positive direction is

a.

b.

c.

d.

8. The three dimensional matrix transformation for rotation with an angle with respect to x-axis in the negative direction is

a.

b.

c.

d.

9. When looking towards the origin from a positive co ordinate position on each axis, which is the positive rotation directiona. clock-wiseb. counter clock-wisec. up side downd. upward

0. The x-shear maintains the coordinates of which of the following directions constanta. xb. yc. zd. y and z

1. The y-shear maintains the coordinates of which of the following directions constanta. y

b. x and zc. x,y and zd. only z

2. The z-shear maintains the coordinates of which of the following directions constanta. zb. y and zc. only yd. x and y

3. The three-dimensional matrix transformation for reflection of a point with respect to xy-plane

a.



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b.

c.

d.

4. Two sucessive reflections about an axis

a. non-commutativeb. do not change the original object positionc. reflects the object to neigbhour quadrantd. reflects the object to diogonally opposite quadrant

5. In 3-D space the reflections are performed abouta. a pointb. an axisc. a planed. an hyper plane

6. If a given object is reflected about xy plane, the co-ordinates of which axis donot change.a. xb. yc. zd. x and y

7. If a given object is reflected about xy, plane the co-ordinates of which axis do changea. xb. yc. zd. x and y

8. Let AV

and AN

are the transformations for aligning the vectors V and N with vector K, passing through z-axis, respectively. Then the transformation

which aligns the vector V with the vector N isa.

b.

c.

d.

9. Three-dimensional matrix transformation for reflection of a point with respect to yz-plane

a.

b.

c.

d.

0. Three-dimensional matrix transformation for reflection of a point with respect to zx-plane

a.

b.

c.

d.

1. Basic transformation matrices for rotation, scaling and mirror reflection are defined to apply about _ _ _ _ _ _ _ _ _ , _ _ _ _ _ _ _ _ _ _ _ and _ _ __ _ _ _ _ _a. axis, origin, plane

b. axis, axis, planec. plane, origin, planed. axis, origin, axis

2. To align an arbitrary vector with any one of the three principal axis, howmany basic rotations are to be performeda. 3b. 2c. 1d. 4

3. To make an arbitrary plane to be aligned with xy plane, the normal of the plane is to be aligned witha. z-axisb. x-axisc. y-axis



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b.

c.

d.

7. The operationsi) shear the view colume so that the centerline of the frustum is perpendicular to the view plane andii) scale the view volume with a scaling factor that depends on 1/z in the same sequence, define

a. perspective - projection transformationb. parallel - prodection transformationc. isometric - projection transformationd. orthogonal - projection transformation

8. The viewing coordinate description of the scene are projected onto the prodection pane ina. modelling transformationb. viewing transformationc. projection transformationd. workstation transformation

9. In the viewing pipeline, the visible surface identification and surface-rendering procedures are performed ina. modelling transformationb. viewing transformationc. prodection transformationd. workstation transformation

0. A class of visible surface detection algorthms compare objects and parts of objects to each other within the scene definition to determine whichsurfaces should be labelled as visible . This categoy of algorthms is called as

a. Object - space methodsb. image-space methodsc. imaginary methodsd. objective methods

1. A category of visible surface detection algorithms in which the visibility is decided point by point at each pixel position on the projection plane, arecalled asa. object-space methodsb. image-space methodsc. imaginary methodsd. objective methods

2. Coherence property is used in visible surface detection algorithms toa. speed-up the processb. increase the precisionc. speed-up the process and to increase the precisiond. make the algorithm easy to understand

3. Coherence methods are used to take advantage ofa. regularities in a scene

b. irregularities in a scenec. computational power of computerd. precision of image capturing equipment

4. The equation of polygon surface is Ax +By+Cz+D=0. Examining of which coefficeant is sufficeant to determine the visibilityof polygon surfacea. Ab. Bc. Cd. D

5. In a right handed viewing system with viewing direction along the positive Zv

axis, the polygon is a back face if

a. c ;= ;0b. c 0c. c ; ;0

d. c ; ;0

6. The surface normal of a polygon surface is N, and V is a vector in the viewing direction from the eye, then this polygon is a back face ifa. V ; ;. ; ;N ; ;< ; ;0b. V ; ;. ; ;N ; ;> ; ;0c. V ; ;. ; ;N ; ;= ; ;0

d. V ; ;. ; ;N ; ; ; ;0

7. In a right handed viewing system with viewing direction along the negative Zv

axis, the polygon is a back face if

a. c ;= ;0b. c 0c. c ; ;0

d. c ; ;0

8. A point (x,y,z) is "inside" a polygon surface with plane parameters A,B,C and D ifa. Ax+By+Cz+D =0b. Ax+By+Cz+D 0d. Ax+By+Cz+D 0

9. Another name for depth-buffer method for visible surface detectiona. z buffer algorithmb. depth - sorting algorithmc. scan - line algorithmd. painter's algorthm

0. Howmany buffers are used in z-buffer (depth buffer) algorithma. 1b. 2c. 3d. 0

1. In z - buffer algorithm referesh (frame) buffer stores the values ofa. depthb. intensityc. depth and intensityd. entensity and enteration number

2. In which of the following algorithms, the object surfaces need not be polygons



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a. Z-bufferb. List - priorityc. Depth - sortd. Binary space partitioning

3. In z-buffer algorthm, the z-buffer (depth buffer) stores the values ofa. depthb. intensityc. depth and intensityd. intensity and interation number

4. Depth value for a surface position (x,y) are calculated from the plane equation Ax+By+Cz+D=0 asa.

b.

c.

d.

5. If the depth value is z at position (x,y) an the plane Ax+By+Cz+D =0, then the z value at position (x+1, y) is determined bya.

b.

c.

d.

6. In which of the following algorithm the polygons in the scene are grouped into clustersa. List priorty algorithmb. BSP tree algorithmc. scane-line algorithmsd. Z-buffer algorithms

7. Which of the following algorithms, is well suited when the view point changesa. List priority algorithmb. BSP tree algorithmc. Scan-line algorithmd. Z-buffer algorithm

8. In BSP tree algorthm, the polygons in a cluster are displayed in

a. The order of increasing plane priorityb. the order of decreasing plane priorityc. large clusters to small plane orderd. small clusters to small plane order

9. Which of the following is false about BSP tree algorithma. polygons in the scane are grouped into clustersb. suitable for varying view pointc. algorithm uses recursive approachd. space insentensive processing

0. In BSP tree, the correct priority order polygon list can be obtained usinga. in-order tree walkb. pre-order tree walkc. post-order tree walkd. Breadth first order tree walk

1. In the BSP trees, the internal nodes and the leaves respectively corrspond toa. partitioning planes, regionsb. regions, partitioning planes

c. visible regions, invisible regionsd. invisible regions, visible regions

2. In BSP tree algorithm the clusters are displayed ina. The order of increasing cluster priorityb. the order of decreasing cluster priorityc. large clusters to small clusters orderd. small clusters to large clusters order

3. Area sub division method for visible surface detection, is essentially aa. object space operationb. image space operationc. both object space and image spaced. neither object space nor image space

4. In area - subdivision method, if the viewing area with a resolution of 1024 by 1024 is sub divided 10 times, the sub area reduces toa. 2 by 2b. 10 by10c. 11 by 10d. a point

5. Which of the following is not a possible relationship between polygon surfaces and a rectangular area defined in area-sub division methoda. surrounding surfaceb. over lapping surfacec. inside surfaced. cutting surface

6. Which of the following is not a possible relationship between polygon surfaces and a rectangular area defined in area-sub division methoda. inside surfaceb. outside surfacec. trivial surfaced. surrounding surface

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