CS2401-COMPUTER GRAPHICS - KEY

VII - SEMESTER- CS2401-COMPUTER GRAPHICS - KEY

PART-A

1. Write down the equation for Cartesian slope intercept.

y=mx+b

m- slope of the line

b is the y intercept                                                        

2. Differentiate window and view port.

window defines what is to be viewed

viewport defines where it is to be defined

3. What is parallel projection?

Parallel projection is a method to project points on the object  surface along parallel lies on to the display plane.

4. What is perspective projection?

Perspective projection is a method to project points to the display plane along converging paths.

5. Specify the purpose of color model.

Color model are used to represent behaviour and effectiveness of colors.

describes Purity, Brightness and hue.

6. Write different types of motion specifications.

Direct motion specification

Goal directed motion specification

Dynamic and kinematic specification

7. What are two types of smooth shading?

Gouraud shading

phone shading

8. What is shading model?

The shading model attempts to model how light that emanates from light sources would interact with objects ina scene. the shading model dictates how light is scattered or reflected from surfaces.

9. List out some properties of fractals.

Self similar

Formatted by iteration

Fractional dimension

Form is extremely irregular or fragmented

10. What is ray tracing?

Ray tracing also called as ray casting , it is a technique for generating an image by tracing the bath of light through pixels in an image and simulating the effects of its encounters with virtual objects.

PART-B

11. a)         Explain in detail about the Bresenhams line drawing algorithm. (16)

read starting and end point.

derive decision parameter po

draw diagram 

calculate remaining points

b)         Briefly explain about the midpoint algorithm for drawing the circle.      (16)

read r and center point (xc,yc)

F_circle(x,y)=x²  +y²-r ²

F_circle(x,y)={^{<0 if (x,y) is inside the ellipse    , =0  if (x,y) is on the ellipse ,  >0 if  (x,y) is outside of ellipse}}

derive decition parameter po=5/4 -r

write algorithm with midpoint diagram

12. a)         Explain briefly about the 3D transformations with example.                   (16)

Explain translation, rotation,scaling

also explain composite transformation

b)         Explain in detail about the 3D viewing and clipping.                                (16)

Explain what is viewing

draw viwing pipeline

transformation of world and viewing coordinates

explain projection concepts

clipping concepts.

13. a)         Describe HSV, XYZ, CIE,CMYand RGB color model.                            (16)

RGB and CMY Color Models

1.

HSV Solid

2.

b)         What is animation? Explain the steps to design an animation sequence.

An animation sequence is designed with the following steps.

Story board layout 

Object definition

Key frame specification

Generation of in between frames

14.       a)         Discuss briefly about the process of creating shaded objects.

b)         Explain how to add surface texture to faces of a mesh object.

15.       a)         Explain in detail about Mandelbrot set.    

The Mandelbrot set is a mathematical set, a collection of numbers. These numbers are different than the real numbers that you use in everyday life. They are complex numbers. Complex numbers have a real part plus an imaginary part. The real part is an ordinary number, for example, -2. The imaginary part is a real number times a special number called i, for example, 3i. An example of a complex number would be -2 + 3i.

The number i was invented because no real number can be squared (multiplied by itself) and result in a negative number. This means that you can not take the square root of a negative number and get a real number. When you take the square root of a number, you find a number that can be squared to get that number. The number i is defined to be the square root of -1. This means that i squared is equal to -1. So when you square an imaginary number you can get a negative number. For example, 3i squared is -9.

Real numbers can be represented on a one dimensional line called the real number line. Negative numbers like -2 are plotted to the left of zero and positive numbers like 2 are plotted to the right of zero. Any real number can be graphed on the real number line.

Since complex numbers have two parts, a real one and an imaginary one, we need a second dimension to graph them. We simply add a vertical dimension to the real number line for the imaginary part. Since our graph is now two-dimensional, it is a plane, the complex number plane. We can graph any complex number on this plane. The colored dots on this graph represent the complex numbers [2 + 1i], [-1.5 + 0.5i], [2 - 2i], [-0.5 - 0.5i], [0 + 1i], and [2 + 0i].

Graphing the Mandelbrot set

The Mandelbrot set is a set of complex numbers, so we graph it on the complex number plane. However, first we have to find many numbers that are part of the set. To do this we need a test that will determine if a given number is inside the set or outside the set. The test is based on the equation Z = Z² + C. C represents a constant number, meaning that it does not change during the testing process. C is the number we are testing, the point on the complex plane that will be plotted when testing is complete. Z starts out as zero, but it changes as we repeatedly iterate this equation. With each iteration we create a new Z that is equal to the old Z squared plus the constant C. So the number Z keeps changing throughout the test.

We're not really interested in the actual value of Z as it changes, we just look at its magnitude. The magnitude of a number is its distance from zero. For example, the number -9 is a distance of 9 from zero, so it has a magnitude of 9. The magnitude of a complex number is harder to measure. To calculate it, we add the square of the number's distance from the x-axis (the horizontal real axis) to the square of the number's distance from the y-axis (the imaginary vertical axis) and take the square root of the result. In this illustration, a is the distance from the y-axis, b is the distance from the x-axis, and d is the magnitude, the distance from zero.

As we iterate our equation, Z changes and the magnitude of Z also changes. The magnitude of Z will do one of two things. It will either stay equal to or below 2 forever, or it will eventually surpass two. Once the magnitude of Z surpasses 2, it will increase forever. In the first case, where the magnitude of Z stays small, the number we are testing is part of the Mandelbrot set. If the magnitude of Z eventually surpasses 2, the number is not part of the Mandelbrot set.

b)         What is Iterated Function System (IFS)? Explain in detail.

IFS stands for Iterated Function System. Fractals of this type are created by applying one of a number of functions, chosen randomly from the rules set up for the IFS, repeatedly to an initial point, and graphing each new point. IFS stands for Iterated Function System. Fractals of this type are created by applying one of a number of functions, chosen randomly from the rules set up for the IFS, repeatedly to an initial point, and graphing each new point.