Computer Graphics — DU B.Sc. (Hons) Computer Science Previous Year Question Papers

Answer all parts of a question together. 1. (a) State any two properties of Bezier curve. 2 (b) What are trace points ? How are they different from principal vanishing points? 2 (c) Differentiate between the RB and CMY colour models by listing any two properties of each. 2 (d) Write steps to design animation sequence. 3 (e) Define resolution, persistence and aspect ratio. 3 / What is anti-aliasing? State any one method to reduce or prevent aliasing in computer graphics. 3 (g) What are homogenous coordinates? What is their importance? (h) Consider the rectangle with vertices (0, 0), (0, 2), (3, 0), (3, 2). Find new coordinates of the rectangle with a scaling of 2 along x-axis and 3 along y-axis. Give the transformation matrix and the final coordinates. 4 (2) Differentiate between the following 4 (i) Orthographic and Oblique projection (ii) Cabinet and Cavalier parallel projection (j) List and explain the data structures used in scan line polygon filling 2. (a) Using homogeneous 4 × 4 transformation matrices, rotate the point (1, 2, 3, 1) by 90° about the x-axis, y-axis and z-axis, write the coresponding rotation matrices and compute the new coordinates after each rotation. 7 (b) Explain the architecture of raster display system with integrated display processor. Write four differences between raster scan display and random scan display. 8 3. (a) Write a short note on hidden surface removal. Explain depth sort algorithm for visible surface determination. 7 (b) Perform a three-point perspective projection onto z = 0 plane of unit cube, where centre of projection along x-axis is X, = 10, along y-axis is Yc = -10 and along z-axis is ze = - 10. 8 (a) Find the equation of a Bezier curve with the following four control points: 7 Boll 0], B1l3 31, Bg[6 3), Bgl8 1l. Determine any two points lying on the curve. (b) Derive the basis matrix for Hermite curve. Find the Hermite curve passing through the starting point PO = (2, 3) and end point P1 = (6, 5), with tangent vectors RO = (1, 2) at PO and tangent R1 = (2, 1) at P1. 8 5. (a) Use Cohen Sutherland algorithm to clip a line P(70, 20) and Q(100, 10) to clip a line against a window with lower left-hand corner (50, 10) and upper right-hand corner (80, 40). 7 (b) Explain homogenous coordinates. What is their importance? Show that a 2D reflection about the x-axis followed by 2D reflection about the line y = x is equivalent to a pure rotation about the origin. 8 (a) Exlain Z-buffer algorithm. Write two advantages and two disadvantages of Z-buffer algorithm. 7 (b) State the rules used to match or equalize the number of edges in the shapes at key frames "K" and "k+1" in an animation sequence. Then, using these rules, show how a triangle can be converted into a pentagon. 8 7. (a) Given the centre coordinates (0, O) and radius = 10. Generate the points of . the first octant of the circle using mid-point circle drawing algorithm. 7