Ping (zestyping) wrote,
Ping
zestyping

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How to give an introductory computer graphics lecture.

Ingredients:

  • three 3-foot, 7/8-inch wooden dowels, spraypainted red, green, and blue respectively
  • one 3-foot, 7/8-inch wooden dowel, cut into three 1-foot lengths, each wrapped in a helix of masking tape and spraypainted red, green, and blue respectively
  • two plastic 3-way elbow joints, inner diameter 7/8 inch
  • one cardboard house, roof spraypainted red with a scribble on one side
  • one shiny metal tea kettle
  • one music CD
  • one piece of yellow perspex
  • one yellow plastic binder
  • one piece of broken mirror
  • one sheet of white paper
  • one large blue inflated exercise ball
  • one bouncy rubber ball

Directions:

  1. Show a couple of nice examples of computer graphics, one realistic and one abstract.
  2. Demonstrate the interdisciplinary nature of computer graphics by attempting to define it.
  3. Plunge the room into total darkness. Tell the audience they can have a minute to relax.
  4. Put up a slide filled with pure cyan. (Because cyan is such a light colour, and because the cyan in the sky causes people to be accustomed to a wide variation in cyan content between indoor and outdoor lighting, the slide will appear white to most people. I know this will sound hard to believe until you try it with a real projector in a completely dark room.) Ask the audience whether they believe visual perception is objective.
  5. Hold up the red 3-foot dowel in the cyan light. Ask the audience what colour it is. It will look grey. Suggest that since it's in "white" light, it must be grey.
  6. Flip to the next slide, a slide filled with pure white. The rod will turn bright red.
  7. Keep flipping slides through various colours, holding up the coloured rods in the light, and ask the audience why they see the colours they're seeing.
  8. Put up this slide. Ask for a brave volunteer to describe what's on the screen. (The usual response is something like "the left side is yellow with a pinkish box in it and the right side is pinkish with a yellow box in it".)
  9. Flip to the next slide to demonstrate that the inner yellow and the inner pink are actually the same colour.
  10. Show text in various colours against a white background. Ask why the yellow text is so much harder to read than the other colours.
  11. Display a chart of the sensitivity of cones in the eye, and explain how the lack of sensitivity to blue accounts for the illegibility of the yellow text.
  12. Pull out the house. Ask why the roof of the house is red.
  13. Demonstrate the difference between diffuse and specular reflection using the mirror and the white sheet of paper.
  14. Demonstrate the difference between reflection and transmission using the yellow perspex and the yellow plastic binder.
  15. Demonstrate the difference between ordinary reflection and anisotropic reflection using the shiny tea kettle and the CD.
  16. Take a break.
  17. Put the red, green, and blue 3-foot rods into one of the three-way elbow joints to make a world coordinate frame.
  18. Put the red, green, and blue spiral-striped 1-foot rods into the other three-way elbow joint to make an object coordinate frame.
  19. Wave the frames around to demonstration translation in various directions and rotation about the various axes.
  20. Explain the right-hand rule.
  21. Demonstrate combined translation and rotation, and point out that the order of transformations makes a difference.
  22. Pull out the big blue exercise ball and ask the audience how to model it in the computer.
  23. Bring up a model of a sphere on the screen, rendered only with points.
  24. Switch from points to a wireframe.
  25. Compare the polygonal model to a NURBS sphere model.
  26. Bring up a wireframe model of the house on the screen.
  27. Ask the audience why the model of the house doesn't look like the real house.
  28. Introduce flat shading with no lights.
  29. Point out that even though the sides of the house are all brown, they appear different brightnesses based on their orientation to the light. Turn on lighted shading.
  30. Point out the scribble. Turn on texture mapping.
  31. Point out the texture of the cardboard surface. Turn on bump mapping.
  32. Flip through some slides demonstrating antialiasing, soft shadows, Gouraud and Phong shading, depth cueing, and motion blur.
  33. Explain the role of physical simulation and dynamics using the rubber bouncy ball.
  34. Describe kinematics by waving around your arms and legs.
  35. Demonstrate the importance of curved motion and slow-in, slow-out timing using some more slides.
  36. Conclude.
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