Class Notes

  1. Who am I
    1. Nice guy
    2. Qualified (run web site with 3500 people/week and 117,000 hits/day 200,000 people so far)
  2. How class is run
    1. Some lecture, mostly hands on
    2. Interrupt as you will
    3. Can eat food
    4. Will have a break
    5. Be nice to hardware
    6. Standard day will be I talk for 20 minutes, you work for an hour, break, repeat, quit
  3. What will we learn
    1. How browsers interperate images
      1. Built-in types vs. plugins
    2. What the image types are
      1. Size, quality, etc
    3. How to make images
    4. VRML
  4. How browsers deal with images
    1. Built-in means that Netscape knows how to handle it
      1. JPG
        1. Lossy but can vary quality as needed
        2. Small and fast
        3. Horrible for repeated edits because of repeated losses
      2. GIF
        1. Lossless
        2. Bigger and slower
        3. Does great for line drawings but still very good for pictures
          4. Original GIF 95% Quality JPG 50% Quality JPG 10% Quality JPG
          292K bytes 167K bytes  29K bytes 11K bytes
           
    2. Plug-in means that netscape only knows the 'type' of the image, and the program to run to display it.
      1. Can be any type, including types not thought of by Netscape Inc.
      2. "Display" can mean anything, including play the sound or release the smell.
      3. VRML and all the cool multimedia types are all plugins.
  5. What is VRML
    1. Pronouced "vermal"
    2. Means "Virtual Reality Modeling Language"
    3. Is a way of describing
      1. 3d objects with textures, colors, and anchors (links)
      2. viewpoints
      3. lights
      4. motion
    4. VRML is an industry standard, so lots of viewers can show it.
  6. How to make VRML?
    1. Use a text editor, write vrml
      1. Maximally powerful, but very slow and painful for the writer
    2. Use a VRML based 3d graphics editor
      1. Easy to use, but can be imprecise with positioning
      2. Only allows features built into the editor
    3. Use a different editor like AutoCAD, and convert
      1. Generally loose features not built into the other editor, like links
  7. VRML Basics
    1. The world has three axis
      1. X means left and right
      2. Y means up and down
      3. Z means toward you and away from you
      4. If you turn, the axis don't move, but the meaning change (think about it)
    2. VRML worlds consist of objects and nothing but objects
      1. Objects have a type (box, cylinder, cone, light, viewpoint, group, etc)
      2. Objects have a scale (how big it is)
      3. Objects have a translation (where is the object)
      4. Objects have a rotation (which direction does it point)
      5. Objects have a surface (color, texture, transparency, etc)