MP4E06

NANY ANG TECHNOLOGICAL UNIVERSITY

SEMESTER 2 EXAMINATION 2011-2012

MP4E06 - VISUALIZATION AND VIRTUAL REALITY IN PRODUCT DESIGN

April/May 2012 Time Allowed: 2 hours

INSTRUCTIONS

1. This paper contains FOUR (4) questions and comprises THREE (3) pages.

2. Answer ALL questions.

3. All questions carry equal marks.

4. Figure 1 in Question 1 is given in Attachment 1 in a separate sheet.

5. This is a CLOSED-BOOK examination.

1. Attachment 1 contains Figure 1 showing two shaded images of the same object. Image 1 is the display of the object while it is being worked on in a CAD system, such as SolidWorks. Image 2 is that of an image intended as the final rendering for publication.

(a) Explain the technique used to produce Image 1. State the reasons behind the use of the technique for display while developing a model.

(6 marks)

(b) Explain the technique used to produce Image 2. (5 marks)

(c) State the reason why the technique used for Image 2, despite the high quality images it can produce, is not used when developing a model. Your answer should explain the factors contributing to the reason.

(4 marks)

(d) Suggest one method by which the effect of the reason in (c) above may be reduced. Explain how your method works.

(4 marks)

(e) The high quality of Image 2 is due to a number of display attributes absent in Image 1. Identify two of these attributes and explain how they may be accounted for.

(6 marks)

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MP4E06

2(a) Explain the stages in the transformation of an object in 3D world coordinates to an image displayed on a computer screen. State the coordinate transformations required at each stage.

(7 marks)

(b) Figure 2 shows a triangle, which is part of a facetted approximation to a curved surface (not shown). The coordinates of its three vertices, A, B and C, and the directions of the surface normals, NA, Ns and Nc, at the vertices are as given in the figure. P and Q are the mid points of AB and AC respectively, and R is the midpoint of PQ. The surface is green with RGB values (0, 255, 0) and its diffuse reflection coefficient is 0.4. A white point light source (RGB values (255, 255, 255)) located at (1, 20, -14) is the only light source in the scene.

(i) Determine the colour reaching the eye from R due to diffuse reflection only using constant shading.

(8 marks)

(ii) Repeat the same exercise as in (i) using Phong shading. (10 marks)

Note: The surface normals are unit direction vectors; their values are given accurate to two decimal places.

,,, -~- (I 20, -14)

I I ' '

NA (-0.20, 0.97, 0.10)

NB (-0.10, 0.99, 0.10)

X

z

Figure 2

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MP4E06

3. Stereoscopic visualization plays a fundamental role in 3D technology.

(a) What is human stereopsis? What should virtual reality stereoscopic visualization learn from human stereopsis?

(6 marks)

(b) Describe linear polarizing and circular polarizing solutions for 3D stereoscopic visualization with the aid of a diagram for each. Highlight their similarities and differences.

(10 marks)

(c) Name two common auto or glass-free stereoscopic solutions. State their working principles and compare them, using drawings where necessary.

(9 marks)

4. Fork-lifts are indispensable in manufacturing and warehousing operations. Fignre 3 shows the AX/BX 50 Series offork-lifts made by Komatsu.

(a) You are required to design and simulate the fork-lifting operation on the computer. Discuss the modelling tasks you will need to perform in this virtual reality simulation.

(5 marks)

(b) Describe yonr virtual design of the control sub-system in the operating compartment using a software system suitable for virtual reality simulation, such as 3D Studio Max. Highlight the steering wheel functions with the control sub-system and suggest the interactive device(s) you would use for the simulation.

(6 marks)

(c) Detail the design of meters and safety indicators of the fork-lift using yonr simulation system. Create a graphical user interface for the virtual reality simulation.

(6 marks)

(d) Discuss the forks and lifting sub-system, and express how you can simulate the lifting operation using yonr simulation system.

(8 marks)

Front Vlew Side VIew Back VIew

Fignre 3

End of Paper

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MP4E06 VISUALISATION AND VIRTUAL REALITY IN PRODUCT DESIGN

Please read the following instructions carefully:

1. Please do not turn over the question paper until you are told to do so. Disciplinary action may be taken against you if you do so.

2. You are not allowed to leave the examination hall unless accompanied by an invigilator. You may raise your hand if you need to communicate with the invigilator.

3. Please write your Matriculation Number on the front of the answer book.

4. Please indicate clearly in the answer book (at the appropriate place) if you are continuing the answer to a question elsewhere in the book.

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