Definition of Computer
Graphics
Computer aided synthesis of
pictures from non-pictorial form
 Related fields

Image
Processing
Visualization
CAM
Computer Vision
CAD
1
Computer Graphics Goals
Realism
 Interactivity
 Real-time image generation
 Sometimes these goals are mutually
exclusive (more realism = more
calculations = less possibility of realtime image creation)

2
Distinctiveness of CG
Dynamic environment – real-time
image support
 Interactive environment for

The creator
 The consumer

Simulation environment
 Provides an environment for
visualizing large quantities of data.

3
Computer Graphics
“Operations

Modeling
Coordinates of the ‘corners’ of objects
 Primitives (2 & 3D geometric objects)
 Equations that define the 2 & 3D shape
of objects
 Attributes (color, surface texture, etc.)

4
Computer Graphics
“Operations”


Storing (first in memory), then on disk
Manipulating




Change shape
Change position
Change characteristics
Rendering– create a picture by applying
an algorithmic version of the physics of
the real world to create the artificial
image.
5
Computer Graphics
“Operations”

Viewing – display scene from
various viewpoints
6
Major application areas

Business graphics



Much of the profit of CG comes from this area
Low quality (and simple) bar charts, line
graphs, pie charts, presentation graphics
systems
Much effort spent on hardware development
(overhead display panels, film recorders) &
software (charting & presentation graphics) to
support this area
7
Major application
areas

Computer-aided design &
computer-aided manufacturing
(CAD/CAM)



Virtual Plant design -
http://www.cadsystems.com/archiv
e/0003f03.html
777 design –
http://www.boeing.com/commercia
l/777family/background.html
Circuit design and layout http://www.automationstudio.com/
8
Major application areas

Data plotting & visualization

“see” the structure of massive data
sets
 Genomics
-
 Computer
vision -
http://www.neurophys.wisc.edu/~cozzi
/2cb.html
http://www.ri.cmu.edu/project_lists/ind
ex.html
9
Major application
areas

Entertainment
 Film makingToy Story, TRON, Star Wars,
Twister, Perfect Storm, Jurassic Park III -
http://cgw.pennnet.com/Articles/Article_Display.cfm?S
ection=Articles&Subsection=Display&ARTICLE_ID=108
471


Video Games Music Videos
http://graphics.stanford.edu/
• Morphing – transform one object into another http://www.cs.clemson.edu/~rmg/homepage.html
10
Major application areas

Computer Art

Paintbrush programs
• Graphics tablet
(digitizer)
• Stylus (brush shapes,
sizes, colors)
• http://cgw.pennnet.co
m/Articles/Article_Disp
lay.cfm?Section=Articl
es&Subsection=Displa
y&ARTICLE_ID=10850
2
11
Reasons for using of CG

User can take in more information

Tables versus graphs
 Easy to make changes
 Circuit design
 Can simulate
 Auto design
 Flight simulators -
http://berkelium.com/OpenGL/flight.html
 Can do the impossible
 Not obey the laws of physics
• Captain Kirk and USS Enterprise travel through spiral
interior of DNA molecule
12
Why is CG hard?
Computationally expensive
 Still developing new algorithms for
realism


Regular objects easy
• Surface of revolution

Surface texture
• Toys vs people
• Texture mapping
13
Why so Hard, cont.


Imperfections
Reflectivity

Matt surfaces versus
specular surfaces
14
Why so hard continued

Motion



Model by hand – animators and key frames
Model by physical equations
Motion capture
• http://cgw.pennnet.com/Articles/Article_Display.cfm?Secti
on=Articles&Subsection=Display&ARTICLE_ID=108465

Fur, Fire, Fern Fun

Dynamic systems -
http://cgw.pennnet.com/Articles/Article_Display.cfm?Section
=Articles&Subsection=Display&ARTICLE_ID=108473

“grow” the processes – particle systems, etc
15