Midterm Study Guide Corrections
- Better solution to problem 2.b.2:
TRUE -- the lengths of lines do not vary with distance from the
viewer, and lines that are parallel in world coordinates will
remain parallel after projection.
- Correction to solution to problem 2.b.4:
TRUE -- Parallel projection is an affine transformation that does
*not* preserve angles after projection.
- Clarification in problem 3:
The viewer is assumed to be looking down the +z axis for this
problem, so larger z is further away. To think of this problem in
terms of the lecture notes, where the viewer is looking down the -z
axis, you need to reverse the comparisons (swap "<" and ">").
-
Correction to solution to problem 4:
i. The storage is in the worst case N^2 not 2^N.
-
Problem 1a:
MFR = T(1,0) * R(theta) * T(0,-3/2)
i.e., the leftmost translation needs to be changed.
Likewise in problem 1b.
[One of the previous incarnations of this problem actually carried a
scale transformation down the hierarchy. To clean it up, we moved the
scale into the definition of the object. Unfortunately, a
scale-dependent answer was still left in the solution. My apologies
for not detecting this earlier.]