Computer Graphics - May 2013

Computer Engineering (Semester 4)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks. 1 (a) Explain the method to draw thick line using Bresenham's algorithm.(5 marks) 1 (b) Differentiate between image space and object space. (5 marks) 1 (c) What is aliasing? Explain some antialiasing techniques.(5 marks) 1 (d) Derive the transformation matrix to magnify the triangle A(0,0), B(1,2), C(3,2) to twice its size so that the point C(3,2 ) remains fixed.(5 marks) 2 (a) Explain Liang Barsky line clipping algorithm. Apply the algorithm to line with co-ordinates (30,60) and (60,25) against the window (Xmin, Ymin) = (10,10) and (Xmax, Ymax) = (50,50). (10 marks) 2 (b) Explain parallel and perspective projection. Perform perspective projection of unit cube when the centre projection is at X_c=10, Y_c=10 on to z=0 plane. (10 marks) 3 (a) Derive the composite matrix for reflection of an object about a line y=mx+c. Apply the derived matrix for the object A(4,2) , B(5,3), C(6,2) and D(7,1) on the line y=2x.(10 marks) 3 (b) Derive the midpoint algorithm for ellipse generation. (10 marks) 4 (a) Explain Weiber-Atherton algorithm for polygon clipping. What are its advantages over other polygon clipping algorithms? (10 marks) 4 (b) Explain the different Raster techniques and the transformation associated with it.(10 marks) 5 (a) Explain Painter's algorithm. (10 marks) 5 (b) Explain Gouraud and Phong shading with their advantages and disadvantages.(10 marks) 6 (a) Explain computer assisted animation and frame by frame animation. (10 marks) 6 (b) Explain scan line fill algorithm with suitable example. (10 marks) 7 (a) Explain RGB and CMY colour models.(10 marks) 7 (b) State the properties of Bezier curves. How a Bezier surface be generated from a Bezier curve?(10 marks)