# Homework 2 - due Feb 12 2009

- Plan to give 2 talks of 10-20 minutes each on a lab from Presentation Topics, or from other similar labs you'd like to cover. Pick three labs that, and three class dates from Feb 17 to March 19. I'll respond with two labs and two dates, trying to give you your first 2. We'll do two talks each class.
- Research how the 3D Superbowl ad worked, and tell me.

# Homework 1 - due Jan 29 2009

## Quaternions

- What is the quaternion {$q_1$} for a {$90^o$} rotation about the X axis?
- What is the quaternion {$q_2$} for a {$90^o$} rotation about the Y axis?
- Compute {$q_1q_2$}. What rotation does that represent?
- Compute {$q_2q_1$}. What rotation does that represent?
- Are those two rotations equal?

## Povray

In this exercise, you need to generate a few pictures with increasing complexity using POV-Ray. We will, in particular, look at how to input a mesh into the scene, and how to improve the rendering of meshes. We use a simplified version of a famous model - Stanford bunny - with 880 triangles.

Helpful links

Directions

- We start with an empty scene.
- Template file: start.pov. Download, read, and render it.
- Replace the floor with checker board.
- Try the different colors specified in colors.inc (list of colors). Notice the first line the beginning of start.pov.

- We next add a sphere and a cone to the scene.
- Put the center of the sphere at (x,y,z)=(-2, 0, 0), and radius=1.
- Put one end of the cone at the center (x,y,z)=(2, -1, 0), and with radius=1. Put the other end of the cone at the center (x,y,z)=(2, 1, 0), and with radius=1.
- Notice that you only see half the sphere. Try modifying the plane to see the entire sphere and cone.
- Adjust your camera so that your output and the relative positions of sphere and cone are as follows:
- Is the image too dark? Try adding another light source.
- Try out some highlights and glass effects.

- We add a simple cube between the sphere and the cone.
- Put the content of cube_triangle into your .pov file.
- Read the code and understand how the cube is constructed out of triangles.
- Render your image, you should get something similar to:

- Replace the cube mesh with the Stanford bunny.
- Hand in or email some screen dumps showing that you got it to work.