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MODULE: EE497 - 3D Interface Technologies
PROGRAMME(S):
MECE MEng Electronic & Computer Engineering
ECE BEng Electronic & Computer Engineering
ECSAO Study Abroad (Engineering & Computing)
ECSA Study Abroad (Engineering & Computing)
TIME ALLOWED: 3 Hours and 40 Minutes
INSTRUCTIONS: Answer all four questions.
Please also read the information on the following page before
commencing the exam.
EE497 – 3D Interface Technologies
Additional instructions specific to the EE497 examination:
? Submissions must be uploaded in doc, docx, odt or pdf format.
? Make sure to show all of your calculations in your answer document. It is
acceptable to include scans of handwritten calculations.
? Any material copied directly from the notes or from any other source will be
considered as plagiarism. So make sure that all of your answers are written in
your own words.
? All answer text must be typed. Handwritten answers will not be accepted.
? In the case of figures, you will be permitted to include photos of hand drawn
figures as well as figures created electronically.
? A scientific calculator may be used when doing this exam.
? All of your answer text and any associated figures must be submitted in a
single document (this requirement will be strictly enforced by loopexam).
? It is strongly recommended that you upload drafts of your submission as you
go.
? There will be four question on the EE497 exam paper and you must answer
all four questions.
? If for some reason you are unable to submit your answers using loopexam
then you should submit them by email instead (to [email protected]).
Note that any emailed submissions will ultimately be uploaded to loopexam
and will subject to the normal plagiarism checks.
? You should give yourself a sufficient amount of time at the end of the exam to
upload your work (or email it if you are unable to submit via loopexam).
Submissions will not be accepted after the exam submission deadline has
passed.
? Documents submitted to loop exam must be less than 250 MB in size.
? Any exam related announcements that I need to make will be sent to your
student email account, so make sure to keep an eye on this over the course
of the exam.
? If you have any queries regarding the content of the exam, contact the module
coordinator (email: [email protected], phone: +353 1 700 8592) and if
you have any problems using loopexam, contact the DCU exam support
centre (email: [email protected], phone: +353 1 700 6151)
Permitted materials: Students will only be permitted to access the module course
materials and their own supplemental notes when doing this exam.
EE497 – 3D Interface Technologies
Semester 2 Examinations 2020/2021 Page 3 of 9 Page 3 of 9
QUESTION 1 (of 4) [TOTAL MARKS: 25]
Q 1(a) [5 Marks]
What is meant by the term interpolation? Compare and contrast the following two-
dimensional interpolation techniques: bilinear and bicubic. Suggest how these
interpolation techniques could be extended into three dimensions.
Q 1(b) [12 Marks]
Describe the steps required to create the star geometry illustrated in Figure 1.1
based on the following parameters: inner circle radius (ri), outer circle radius (ro) and
number of triangles (t). Your description should assume that back face culling will be
used and that the star is centred at (0, 0, 0). Note that the entire shape is located in
the xy-plane and that the dashed elements do not form part of the geometry.
Figure 1.1: A star geometry represented by an inner circle radius (ri),
an outer circle radius (ro) and a number of triangles (t).
Q 1(c) [8 Marks]
What are texture coordinates used for in 3D computer graphics? How would you
generate texture coordinates for the geometry from Part (b)? Note that the dashed
box is used to indicate the relationship between the geometry and the associated
texture image.
[End of Question 1]
EE497 – 3D Interface Technologies
Semester 2 Examinations 2020/2021 Page 4 of 9 Page 4 of 9
QUESTION 2 (of 4) [TOTAL MARKS: 25]
Q 2(a) [5 Marks]
Describe in your own words the operation of the Phong reflection model with
reference to all of its configurable parameters. In the case of the ambient reflection
component, what colour would be perceived at a particular vertex if the ambient light
colour was (0.70, 0.39, 0.57) and the ambient colour of the vertex was (0.34, 0.46,
0.55)?
Q 2(b) [10 Marks]
Describe the operation of the WebGL vertex and fragment shaders with specific
reference to all of the relevant inputs and outputs. How would the vertex and
fragment shaders in Listings 2.1 and 2.2 render the gl.LINE_STRIP geometry
described in Table 2.1? Use a diagram to support your answer.
Listing 2.1: An example
vertex shader.
Listing 2.2: An example
fragment shader.
Vertex
coordinates
Vertex colours
(RGBA)
v0 (1.0, 0.0, 0.0) (0.0, 1.0, 0.0, 1.0)
v1 (0.0, 1.0, 0.0) (0.0, 0.0, 1.0, 1.0)
v2 (-1.0, 0.0, 0.0) (1.0, 0.0, 0.0, 1.0)
v3 (-2.0, 1.0, 0.0) (1.0, 0.0, 0.0, 1.0)
Table 2.1: Vertex information for a simple
gl.LINE_STRIP geometry.
Q 2(c) [4 Marks]
What is the purpose of a LOD scene graph node? Use an example scene graph
containing a LOD node to support your answer.
[Question 2 continued overleaf…]
EE497 – 3D Interface Technologies
Semester 2 Examinations 2020/2021 Page 5 of 9 Page 5 of 9
Q 2(d) [6 Marks]
Compare and contrast the approaches to animation used in X3D and OSG.JS with
reference to the code samples provided below. Your answer should include scene
graph diagrams and make specific reference to the rates of rotation and axes of
rotation.