# CS602 Assignment 3 Solution and Discussion

• Total Marks = [20]
Assignment No. 03
Semester: Fall 2019
Computer Graphics – CS602
Total Marks: 20

Due Date: 22/01/2020

Objectives:
Objective of this assignment is to assess the understanding of students about
the concepts of lighting, mathematics of lighting and shading, color intensities, color mixing techniques, color saturations, techniques to deal saturation and light phenomena when it passes through objects.

Instructions:

1. You should consult the recommended books, PowerPoint slides and audio lectures to clarify your concepts.
2. You are supposed to submit your assignment in .doc format. Any other formats like scan images, PDF, ZIP, RAR and BMP etc, will not be accepted.
3. It should be clear that your assignment will not get any credit if:
• The assignment is submitted after the due date.
• The assignment is copied from the Internet or any other student.
• The submitted assignment does not open or file is corrupt.

Note: No assignment will be accepted after the due date through email in any case (load shedding, server down, internet malfunctioning etc.).
It is recommended to upload solution file at least two days before its closing date.

For any query about the assignment, contact at [email protected]

Question No:1 Marks=15
Suppose a Movie maker wants to create a night vision effect in a scene. The scene has light grey colored chair having RGB components (0.5,0.7,0.8). He has used four light sources. In terms of RGB the intensities of light sources are l1(0.4,0.7,0), l2(0.2,0.1,0.5), l3(-0.5,-0.6,0.5) and l4(-0.1,-0.2,0 ) ; Light source 3 and light source 4 are dark lights having negative colors.

a) What will be the final light intensity? (5 marks)
b) Calculate the overall color contribution of light in relation to the object surface? (5 marks)
c) What color component(s) will remain absent from the scene? (3 marks)
d) Which color the object will look like in presence of the light sources? (2 marks)
Hint: (You may check final color intensities given in color.pdf file)

Question No 2: Marks=05
Fiber Optics are widely used as optic cables to transmit light signals over long distances with minimal loss of data. It works on the principle of total internal reflection.

In order to simulate the fiber optic in computer graphics, calculate the critical angle where the inner core of fiber has index of refraction 1.5 while the cladding has index of 1.3.

BEST OF LUCK

• Q. 1 Solution Idea

a. Final intensity of light is (0.4,0.7,0) +(0.2,0.1,0.5) +(-0.5, -0.6,0.5) +(-0.1, -
0.2,0) = (0,0,1)

b. Overall Contribution: id ⨂ cs = (0,0,1) ⨂ (0.5,0.7,0.8)
= (0,0,0.8)

c. Red and Green components will remain absent from the scene

d. The object will look blue in the presence of light sources.

Q. 2 Solution Idea:

1

3

3

2

3

1

2

5
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