BE Computer Engineering (IOE, TU) Computer Graphics (IOE, CT 605 / ENCT 201) Question Paper 2078
This is the official BE Computer Engineering (IOE, TU) Computer Graphics (IOE, CT 605 / ENCT 201) question paper for 2078, as set in the regular annual examination. It carries 80 full marks and a time allowance of 180 minutes, across 12 questions. On Kekkei you can attempt this Computer Graphics (IOE, CT 605 / ENCT 201) past paper online with a timer, get instant AI feedback and step-by-step solutions, and track the topics where you lose marks — completely free. Whether you are revising for your BE Computer Engineering (IOE, TU) Computer Graphics (IOE, CT 605 / ENCT 201) exam or solving previous years' question papers, this 2078 paper is a great way to practise under real exam conditions.
Section A: Long Answer Questions
Attempt all / any as specified.
(a) Derive the decision parameter for Bresenham's line drawing algorithm for a line with slope 0 < m < 1, and state how the algorithm is generalized to handle lines of arbitrary slope. [7]
(b) Using the midpoint circle drawing algorithm, compute and tabulate the pixel positions in the first octant for a circle of radius r = 8 centred at the origin. [5]
(a) Explain why homogeneous coordinates are used in computer graphics. Obtain the composite transformation matrix required to reflect an object about the line y = x + 2, clearly stating each elementary transformation in order. [8]
(b) A triangle has vertices A(2, 2), B(6, 2) and C(4, 6). Find the coordinates of the triangle after it is rotated 90° anticlockwise about the point (4, 2). [4]
(a) Distinguish between parallel and perspective projection. Derive the perspective projection transformation matrix for a centre of projection located at a distance d from the projection plane along the z-axis, and explain the effect of vanishing points. [8]
(b) Write down the transformation matrix to rotate a 3D object about an axis parallel to the z-axis passing through the point (x0, y0, 0) by an angle θ. [4]
(a) Describe the Cohen-Sutherland line clipping algorithm. Explain the significance of region (outcodes) and the conditions for trivial acceptance and trivial rejection. [7]
(b) Using the Cohen-Sutherland algorithm, clip the line segment from P1(−10, 30) to P2(40, 5) against a rectangular clipping window with corners (xmin, ymin) = (0, 0) and (xmax, ymax) = (30, 30). Show the intersection calculations. [5]
Section B: Short Answer Questions
Attempt all / any as specified.
Explain the Z-buffer (depth-buffer) algorithm for hidden surface removal. Compare it with the back-face detection method, stating one advantage and one disadvantage of each.
State the Phong illumination model and write its equation including ambient, diffuse and specular components. Differentiate between Gouraud shading and Phong shading.
What are Bezier curves? List the important properties of a Bezier curve. A cubic Bezier curve is defined by control points P0(1, 1), P1(2, 4), P2(5, 4) and P3(6, 1); compute the point on the curve at parameter u = 0.5.
Explain the scan-line polygon fill algorithm. Describe the role of the edge table and the active edge list, and how the algorithm handles vertices that are local minima or maxima.
Describe the Sutherland-Hodgeman polygon clipping algorithm. Explain, with the help of a diagram, the four possible cases that arise when an edge is clipped against a single window boundary.
Differentiate between raster scan and random (vector) scan display systems. What is meant by aspect ratio and frame buffer of a raster display?
What is a B-spline curve? Explain how B-spline curves provide local control over the curve shape and state two advantages of B-spline curves over Bezier curves.
Explain the depth-sorting (Painter's) algorithm for visible surface determination. Under what circumstances does the simple depth ordering fail, and how can such cases be resolved?