## 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)