CS185c Spring 2019Practice Midterm

Studying for one of my tests does involve some memorization. I believe this is an important skill. Often people waste a lot of time and fail to remember the things they are trying to memorize. Please use a technique that has been shown to work such as the method of loci. Other memorization techniques can be found off the Wiki Page for Moonwalking with Einstein. Given this, to study for the midterm I would suggest you:

• Know how to do (by heart) all the practice problems.
• Go over your notes at least three times. Second and third time try to see how much you can remember from the first time.
• Go over the homework problems.
• Try to create your own problems similar to the ones I have given and solve them.
• Skim the relevant sections from the book.
• If you want to study in groups, at this point you are ready to quiz each other.

The practice midterm is below. Here are some facts about the actual midterm: (a) It is closed book, closed notes. Nothing will be permitted on your desk except your pen (pencil) and test. (b) You should bring photo ID. (c) There will be more than one version of the test. Each version will be of comparable difficulty. (d) One problem (less typos) on the actual test will be from the practice test.

1. Briefly define the following concepts: telepresence, closed-loop VR system, synthetic versus capture VR system.
2. Give code to create an A-Frame HTML page with a cube place in front of the user.
3. Briefly explain how cameras work in A-Frame and how look controls work.
4. What is the the vergence-accommodation mismatch problem? What kind of display can be used to solve it?
5. Define: vection, perceptual training. Give an example of Weber's Law.
6. Express a rotation about the z axis by 60 degree followed by a translation by (1,2,3) as a single homogeneous transformation matrix.
7. Express a rotation about the y axis by 45 degrees using a unit quaternion.
8. Explain how head tracking can be done in WebVR in terms of getting and using matrices to draw a scene.
9. Give a simple optical model for a VR headset, and where and why a lens is used.
10. Describe how one can determine the orientation of a controller using the Gamepad API.