|Subject:||How to give an introductory computer graphics lecture.|
- 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
- Show a couple of nice examples of computer graphics, one realistic and one abstract.
- Demonstrate the interdisciplinary nature of computer graphics by attempting to define it.
- Plunge the room into total darkness. Tell the audience they can have a minute to relax.
- 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.
- 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.
- Flip to the next slide, a slide filled with pure white. The rod will turn bright red.
- 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.
- 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".)
- Flip to the next slide to demonstrate that the inner yellow and the inner pink are actually the same colour.
- Show text in various colours against a white background. Ask why the yellow text is so much harder to read than the other colours.
- 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.
- Pull out the house. Ask why the roof of the house is red.
- Demonstrate the difference between diffuse and specular reflection using the mirror and the white sheet of paper.
- Demonstrate the difference between reflection and transmission using the yellow perspex and the yellow plastic binder.
- Demonstrate the difference between ordinary reflection and anisotropic reflection using the shiny tea kettle and the CD.
- Take a break.
- Put the red, green, and blue 3-foot rods into one of the three-way elbow joints to make a world coordinate frame.
- Put the red, green, and blue spiral-striped 1-foot rods into the other three-way elbow joint to make an object coordinate frame.
- Wave the frames around to demonstration translation in various directions and rotation about the various axes.
- Explain the right-hand rule.
- Demonstrate combined translation and rotation, and point out that the order of transformations makes a difference.
- Pull out the big blue exercise ball and ask the audience how to model it in the computer.
- Bring up a model of a sphere on the screen, rendered only with points.
- Switch from points to a wireframe.
- Compare the polygonal model to a NURBS sphere model.
- Bring up a wireframe model of the house on the screen.
- Ask the audience why the model of the house doesn't look like the real house.
- Introduce flat shading with no lights.
- 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.
- Point out the scribble. Turn on texture mapping.
- Point out the texture of the cardboard surface. Turn on bump mapping.
- Flip through some slides demonstrating antialiasing, soft shadows, Gouraud and Phong shading, depth cueing, and motion blur.
- Explain the role of physical simulation and dynamics using the rubber bouncy ball.
- Describe kinematics by waving around your arms and legs.
- Demonstrate the importance of curved motion and slow-in, slow-out timing using some more slides.