State the reason why we prefer unit x interval or unit y

Question

There are two sections in this question paper:A and B.Section A is compulsory. Attempt any four questions from section B. Parts of a question MUST be answered together.

Q1 (a) State the reason why we prefer unit x interval or unit y interval while scan converting various geometric forms.

(b) Implement DDA algorithm to compute pixels along the line AB from A (0,0 ) to B (-5, -5 ).

(c) Consider a parallel projection with the plane of projection having the normal ( 1, 0, -1) and passing through the origin (0,0,0) and having a direction of projection d = (-1,0,0 ). Is it an orthographic projection ? Justify your answer.

(d) What is anti - aliasing ? Explain any one method of anti - aliasing ?

(e) Determine 3D transformation matrix to scale a line AB in Z - direction by 3.5 by keeping point A fixed. Then rotate the line by 45^ο anticlockwise about X- axis. Given A (10,15,20) and B ( 45,60,30).

(f) Discuss random display system with suitable diagram.

(g) What is the need of using homogeneous coordinate system ? Describe briefly.

(h) Why is it easier to locate hidden surface when parallel projection is used ?

(i) An object is defined with respect to a coordinate system whose units are measured in feet. If an observer's coordinate system uses inches as the basic unit, What is the coordinate transformation used to describe object coordinates in the observer's coordinate system?

(j) What are the different types of accelerations that can be incorporated in a multimedia animation ? Explain any one with suitable graph.

(k) Explain Interlacing technique with suitable diagram.

(l) Explain pointers to an edge list representation of a polygon mesh with suitable diagram.

SECTION B

Q2 (a) Indicate which raster locations would be chosen by Bresenham's algorithm when scan converting a line from pixel coordinate (1 , 1) to (8 , 5).

(b) Derive the basis matrix of cubic Bezier curve.

Q3 (a) Explain with mathematical foundation how we compute Z - depth in Z - buffer algorithm.

(b) Find the condition under which we can switch the order of a rotation and a simultaneous shearing and still get the same result.

Q4(a) Use the Liang Barsky algorithm to clip the following line:

(b) Explain Gamma correction with suitable graph.

Q5 (a) Explain the following with suitable examples:

(i) Vanishing point (ii) Morphing

(b) Using Sutherland Hodgman algorithm clip the following polygon against the given rectangular window:

Q6 (a) A tetrahedron of size 10 units is placed on XY plane with one edge along x - axis (+ ive) and one vertex at origin. Assuming the tetrahedron to be opaque ,evaluate and draw the projected image of the tetrahedron if the center of projection is ( 10,0,0).

(b) When eight - way symmetry is used to obtain a full circle from pixel coordinates generated for 0^ο to 45^ο or 90^ο to 45^ο octant ,certain pixels are set or plotted twice. This phenomenon is sometimes referred to as over striking, Identify the locations where over-strike occurs.

(c) Explain refresh rate in a raster system with suitable numerical example.