Here is how I broke down the marks for most questions (some
of the 5 mark questions aren’t listed because they are more straightforward).
If you think your answer deserves more marks or that I
missed something in determining the correctness of your answer, send an email
that demonstrates this. If indeed I
think you deserve more marks, I’ll ask you to bring in your midterm paper.
Be sure to check my addition!
Number 1
·
2 for the projection role
·
2.5 for the defining parameters (0.5 each)
·
2.5 for the diagram
·
1 for what defining parameters form
·
2 for implication on visualizing game objects
Number 2
·
4 for explaining what homogeneous coordinates
are
o
3 if correct but not quite enough detail
·
4 for explaining the motivation for them
·
2 for giving example of where they are used
o
1 if you give a correct example but offer an
incorrect reason
Number 3
·
For general matrices, 1.5 each for the two
translation matrices and 2 for the rotation
·
5 marks for the second part: 1 mark for each of
four matrices (including the point) and 1 one mark for the correct order
Number 4
·
15 for describing the steps properly
o
4 for defining two vectors using the triangle
points
o
3 for finding the normal via the cross product
of these two vectors
o
4 for defining a vector from the triangle to the
viewpoint
o
4 for computing the cosine of the angle between
normal and vector to the viewpoint (only the sign matters)
·
5 for drawing an accurate picture
o
2.5 if the overall idea is there but it does not
generalize well and/or does not show U, V, W, P, or other parts of the
computation in the first part
o
2 if the diagram is good but based on wrong
method
·
5 for correctly computing whether T is visible
from P
Number 5
·
5 for saying why the transformation computes
Z-values
o
1 if you mention removing shapes outside view
frustum (this will happen before the projection transformation)
·
10 for correct computation
o
7 if correct but not enough math shown to show
full understanding
o
9 if there’s a small error
o
7 if you don’t properly multiply the homogeneous
coordinate of the point with the value in position (4,3) in the matrix to end
up getting zero in the result
Number 6
·
5 for computing orientation
·
7 for computing avatar position
o
5 if you don’t show enough math
o
4 if you don’t normalize the orientation vector
and multiply that by 50 units
·
8 for
avatar’s position and orientation
o
7 if you did not do the math and/or there are
small errors
o
4 if the method is wrong
Number 8
·
2.5/5 for saying the objects occupy the same
space and to pick just one (without saying how)
·
3.5/5 for saying the objects occupy the same
space and to change their z-value
Number 9
·
3/5 for saying the object is outside the “render
distance”
Number 10
·
3 for explaining the purpose
·
2 for the example
o
1.5 if example is good but based on incorrect
understanding of part 1
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