KIGALI INSTITUTE OF SCIENCE AND TECHNOLOGY
INSTITUT DES SCIENCES ET TECHNOLOGIE
Avenue de l'Armée, B.P. 3900 Kigali, Rwanda
INSTITUTE EXAMINATIONS – ACADEMIC YEAR 2012-2013
SEMESTER IIMAINEXAMINATION
FACULTY OF ENGINEERING
COMPUTER & INFORMATION TECHNOLOGY
4th and 3rd YEAR CIT SEMESTER II PART TIME
CIT3322: VIRTUAL REALITY
DATE: ……………..
TIME: 2 HOURS
MAXIMUM MARKS = 60
INSTRUCTIONS
1. This paper contains FOUR (4) questions
2. Answer
- ALL questions in PROBLEM I
and
- any TWO (2) questions from PROBLEMS II, III and IV
3. No written materials allowed.
4. Write all your answers in the answer booklet provided.
5. Do not forget to write your Registration Number.
6. Do not write any answers on this question paper.
PROBLEM I
This question is based on the MATLAB based project for this class. Assuming that Figure 1.1 below shows a simple
Virtual Reality (VR) which is used to simulate a military parade.
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Figure 1.1
You will be principally in charge of the project that will implement this VR and, for fast testing, it was found that
the VR contains the following VRML nodes:
Node
Representation
figure
Represent the “entire” person in the VR
head
The head of the person
leftLeg
The left Leg
rightLeg
The right leg
leftArm
The left Arm
rightArm
The right Arm
During a parade, it is assumed that when each person moves the right leg forward, the left arm moves
backward and when he/she moves the right leg backward, the left arm should move forward. The same exact
procedure applies to the left and right arm. Further, it is assumed that when the person moves forward the right
leg, the head should turn left and when he/she move the left leg forward, the head turns right.
(a) (5 Points)Explain in details how you would achieve this simulation in MATLAB. You can simply draw a
simple block diagram or flowchart illustrating how this can be achieved and make sure to include
different transformations that are needed.(You don’t need to write any code. You may however write
pseudocode if you like)
(b) (5 Points)Explain why you need to use the MATLAB command “vrdrawnow” after each loop iteration
(c) (5 Points)In 3D modeling and virtual environment, there are three commonly used transformations:
translation, rotation and scaling. Explain how each operation works, giving an example in each case.
(d) (5 Points)A point in 2D space can be transformed using translation, scaling and rotation. By default
these transformations are performed centered on the origin. Imagine a point positioned at X and Y coordinates (1, 1). For each of the following transformations give the new position of the point. Note - do
not apply these transformations in succession. In each case begin with the original point.
 A translation by (2, -1);
 A scaling of (2.0, 0.5) about the origin;
 A rotation of 90° clockwise about the origin.
PROBLEM II
A scaling transformation has been described as the following operation:
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(This simply means that the scaling factor is 1.25 along the X axis, 0.5 along the Y axis and 1 along the Z axis).
Has been applied to the object shown in figure 2.1 below.
Figure 2.1
(a) (6 Points)What are the coordinate of vertex 1,2 and 3 of the triangle in figure 2.1?
(b) (9 Points)Give the new coordinates for each vertex on the object
(c) (5 Points)Sketch its new position and shape.
PROBLEM III
A point in 2D space can be transformed using translation, scaling and rotation. By default these
transformations are performed centered on the origin. Imagine a point positioned at X and Y co-ordinates (1,
1).
(a) For each of the following transformations give the new position of the point. Note - do not apply these
transformations in succession. In each case begin with the original point.
(1) A translation by (2, -1);
(2) A scaling of (2.0, 0.5) about the origin;
(3) A rotation of 90° clockwise about the origin.
(b) A more useful transformation allows us to define the center point for the transformation, as well as its
normal parameters.
For example, we could rotate a point by 90° but center this rotation on the point (1, 1). Briefly describe
how you would actually perform this using only the three standard transformations of translation,
scaling and rotation.
(c) A certain operation requires that you both rotate an object by an angle q and scale it by a factor of (Sx,
Sy). The transformation matrices for rotation and scaling are shown below, but this operation can be
simplified by compounding these two matrices into a single transformation matrix. Calculate the single
matrix you would need.
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(d) Using your new transformation matrix, apply it to the object shown in figure 4.1 below. The rotation
angle q is 90° (positive angle = anti-clockwise) and the scaling factor is (1.0, 0.5). Calculate the new coordinates for each vertex of the object (1 to 8) using your transformation matrix, then sketch the new
position of the object.
Figure 4.1
PROBLEM IV
(a)
(b)
(c)
(d)
(5 Points)Explain in your own words what is virtual reality
(5 Points)Explain how virtual reality differs from telepresence and augmented reality.
(5 Points)Give TWO example of applications of VR to illustrate how VR is useful in our modern world.
(5 Points)Give TWO challenges/limitation that VR cannot currently efficiently solve.
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