DOEACC Society 2006 DOEACC C Level C10 Computer Graphics & Animation ( ) - Question Paper

C10-R3: COMPUTER GRAPHICS & ANIMATION
NOTE:
Time: three Hours Total Marks: 100
1.
a) define how the Cyrus-back algorithm determines whether a point on a line is inside,
on or outside a window?
b) describe the
i) one-point perspective transformation
ii) two-point perspective transformation and
iii) three-point perspective transformation. Can multiple faces of an object be
revealed using the perspective projections?
c) elaborate hidden surface problems? How z-buffer algorithm handles them?
d) provide any 1 technique to determine the direction of the reflection vector in
implementing an illumination model.
e) explain the generation of Solid Objects using sweep method.
f) Why do we consider a mathematical spline model using cubic polynomials? Whether
Bezier curves are better than the routine curve fitting techniques for ab initio design of
curves?
g) How far a fixed angle representation avoids the invalid representation problem? What is
gimbal lock? State the Euler angle representatio.
(7x4)
2.
a) Using Cyrus-back algorithm determine whether the line from P(6, -2) to Q(10, 1) will be
visible , partially visible or invisible when clipped to the rectangular window as shown below:
b) An object is to be rotated 60 degree clockwise about an line passing through the origin
and a point (3, 5, 4). obtain the sequence of transformations needed to perform this task.
(10+8)
C10-R3 Page one of two January, 2006
O
4
(8,4)
1. ans ques. one and any 4 ques. from two to 7.
2. Parts of the identical ques. should be answered together and in the identical
sequence.
3.
a) elaborate the methods for degree raising of B-spline curves?
Consider an open third-order B-spline curve initially described by 4 polygon vertices
A(0,0), B(1,1), C(2,1), D(3,0). Subdivide the curve applying Oslo algorithm while
maintaining a open uniform knot vector.
b) compute the 5 3rd order B-spline basis functions using the knot vector X = [0 0 0 one 1
3 three 3] which contains an interior repeated knot value.
(12+6)
4.
a) Consider the rectangle with corners as P(10,5,10), Q(10,25,10), R(25,25,10), S(25,5,10)
and the triangle ABC penetrating the rectangle from the behind where A=(15, 15, 15),
B=(25, 25, five ) and C=(30, 10, 5). presume the observer is located at infinity on the
positive z-axis. If the ray is considered through the pixel at (20, 15), obtain the visible
portion of the scene illustrating every step of the ray-tracing algorithm.
b) obtain the general form of an oblique projection onto the xy plane.
(12+6)
5.
a) discuss how Octrees can be used to represent curved objects. provide algorithms for union
and intersection of object representation using Octrees.
b) discuss phong’s shading model. provide its advantages and disadvantages over Gouraud’s
model.
(10+8)
6.
a) elaborate various techniques used for implementing key frame based animation?
explain the advantages and disadvantages of them.
b) define the two-pass procedure to interpolate the image grids and forming an in
ranging from grid while interpolating 1 image into a different.
(9+9)
7.
a) discuss and compare the Particle System and Flocking System techniques for
animation?
b) elaborate the main forces at work in keeping a bunch of boids behaving like a flock.
explain every of them briefly.
(8+10)
C10-R3 Page two of two January, 2006

Earning:   Approval pending.