## Pokhara University | Old Question Paper

Bachelor of Engineering (BE)

Computer Graphics – Level: Bachelor

Year: 2010 | Semester : Spring

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**Question Paper is Given Below:**

Full Marks: 100 | Pass Marks: 45 | Time: 3 Hrs

*Candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.*

**Attempt all the questions.**

1. a) Discuss the importance of Computer Graphics for the Engineering fields. [7]

b) Compare and contrast between raster scan display and random scan display. [8]

2. a) How long would it take to load a 640 by 480 frame buffer with 12 bits per pixel, if 105 bits can be transferred per second? How long would it take to load a 24-bit per pixel frame buffer with a resolution of 1280 by 1024 using this same transfer rate? [7]

**b) Define the following terms: [8]**

i. Modeling coordinates

ii. Device Coordinates

iii. World coordinates

iv. Normalized coordinates

**OR**

How do you apply symmetry concept while drawing circle. Use midpoint algorithm to digitize circle with radius 10 and centre at (4, 3). [8]

3. a) Consider a triangle ABC with vertices A(1,1), B(6,1), C(6, 6). Obtain the transformed coordinates for this triangle after rotating it about an angle 90˚ and about a reference point (xr, yr) = (3,3). [8]

b) Derive the Bresenham’s line drawing algorithm for |m| > 1. [7]

4. a) What are the different graphical packages available currently? Explain about the few functions associated with any one of them. [8]

b) What is projection? Derive the expression and matrix representation for perspective projection. [7]

5. a) Write down the equation for illumination model at any point due to different light sources. Also, consider the attenuation factor. [8]

b) How can you use depth buffer method for hidden surface problem? [7]

6. a) Write the steps involved in rotating a 3-D object about an axis that is not parallel to any of the coordinate axes. Also, represent the steps in homogeneous coordinate matrix form. [7]

b) What is meant by a project? Explain briefly about project life cycle? [8]

**7. Write short notes on any two: [2 × 5]**

a) Frame buffer

b) Cohen-Sutherland line clipping algorithm

c) Graphics language