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### Transcript of Computer Graphics - Department of Aerospace ae. aerocad/Computer Graphics- Graphics Introduction to...

• Computer Graphics

Dr. S.M. MalaekAssistant: M. Younesi

• Computer Graphics

COMPUTER GRAPHICS, Donald Haern, M. Pauline Baker (Second Edition)

Textbook:Sunday/Tuesday 13:30-15Time:

• Modeling

Computers have become a powerful tool for the rapid and economical production of pictures and models.

There is no area in which graphics displays cannot be used to some advantage.

• What is Computer Graphics?

Computer graphics generally means creation, storage and manipulationof models and images.

• What is Computer Graphics?

Such models come from diverse and expanding set of fields including physical, mathematical, artistic, biological, economical, .

• Model

Model, models, or modeling: a pattern, plan, representation, or description designed to show the structure or working of an object, system, or concept.

• Physical Model

• Physical Model

A physical model is used to mean a physical representation of some things, for example a bolt or the solar system.

• Physical Model

A scale model of the Singapore City Centre.

The geometry of the model and the object it represents are often similar in the sense that one is a rescaling of the other.

• Physical Model

Model of a war scene.

• Physical Model

Model of molecule.

• Physical Model

Cuddly toy

• Mathematical Model

• Mathematical ModelA mathematical mode: it uses mathematical language to describe the behaviour of a system.

Mathematical models are used in the science, engineering, economics and

• Mathematical Model

Examples:Population Growth

Model of a particle in a potential field.

• Mathematical Model

A mathematical model describes a system by a set of variables and a set of equations that establish relationship between the variables.

• Economics Model

• Economic Model

In economics, a model is a theoretical construct that represents economic processes by a set of variables and a set of logical and quantitative relationships between them.

• Economic Model

Economic models have two function:

Simplification

Selection

• What is Computer Graphics?William Fetter coined term computer graphics in 1960 to describe new design methods he was pursuing at Boeing.

Created a series of widely reproduced images on pen plotter exploring cockpitdesign, using 3D model of human body.

• What is Computer Graphics?Perhaps the best way to define computer graphics is to find out what it is not. It is not a machine. It is not a computer, nor a group of computer programs. It is not the know-how of a graphic designer, a programmer, a writer, a motion picture specialist, or a reproduction specialist.

Computer graphics is all these a consciously managed and documented technology directed toward communicating information accurately and descriptively.

• What is Interactive Computer Graphics?

User controls contents, structure, and appearance of objects and their displayed images via rapid visual feedback.

• Interactive Computer GraphicsBasic components of an interactive graphics system:

input (e.g., mouse, tablet and stylus, scanner)processing (and storage)display/output (e.g., screen, paper-based printer, video recorder )

• First truly interactive graphics system, Sketchpad, pioneered at MIT by Ivan Sutherland for his 1963 Ph.D. thesis.

Sketchpad in 1963. Note use of a CRT monitor, light pen and function-key panel.

Interactive Computer Graphics

• Before Sketchpad, output via plotters/printers, input via keypunch.

Card punching. IBM 704 . took up a whole room and was capable of about 4,000 arithmetic operations/second.

Interactive Computer Graphics

• The Sketchpad system uses drawing as a novel communication medium for a computer. The system contains input, output, and computation programs which enable it to interpret information drawn directly on a computer display.

Interactive Computer Graphics

• Sketchpad has shown the most usefulness as an aid to the understanding of processes, such as the motion of linkages, which can be described with pictures. Sketchpad also makes it easy to draw highly repetitive or highly accurate drawings and to change drawings previously drawn with it

Interactive Computer Graphics

• Three factors be considered:

Time

Cost

Quality

Interactive Computer Graphics

• Interactive Computer GraphicsCost/Time (\$/hr): Whirlwind, built in early 50s at MIT, cost \$4.5 million and could perform 40,000 additions/second. Mac 512K, list price \$3,195 in 1984, could do 500,000. Today, commodity PCs perform approximately two or three billion operations/second.

• Quality: Eliminates error propagation by using data bases and transfer of data.

Interactive Computer Graphics

• Applications

Computer Aided DesignPresentation GraphicsComputer ArtEntertainmentEducation and trainingVisualizationImage ProcessingGraphics User Interfaces

• Applications Computer Aided Design

A major use of computer graphics in design processes, particularly for engineering and architectural system. But almost all product are now computer designed.

For some design applications, objects are first displayed in a wireframeoutline form.

Wireframe (outline) form shows the overall shape and internal features of objects.

CAD methods are now used in the design of:

Buildings

Automobiles

Aircraft

Watercraft

SpacecraftTextiles

Software package for CAD applications typically provide the designer with a multi-window environment.

Circuits designed by successively placing components into the layout, with the graphics package automatically providing the connections between components.

Animation are often used in CAD applications.

Animation in virtual reality environment are used to determine how system operators are affected by certain motion.

Virtual Reality (VR)Fishtank VR

The manufacturing process is also tied in to the computer description of designed objects to automate the construction of the product.

Architectural Designs

Rug Pattern

• Applications

Presentation Graphics

• ApplicationsPresentation Graphics

Presentation graphics used to product illustrations for reports or to generate 35-mm slides or transparencies for use with projectors.

• ApplicationsPresentation Graphics

Presentation graphics is used to:StatisticalMathematicalScientificEconomic dataManagerial reportConsumer information bulletins

• ApplicationsPresentation Graphics

Typical examples of presentation graphics are:

Bar GraphsLine GraphsSurface GraphsPie Charts

• ApplicationsPresentation Graphics

Typical examples of presentation graphics are:

• ApplicationsPresentation Graphics

Bar Charts

• ApplicationsPresentation Graphics

Line Graphs

0

5

10

15

20

25

30

1 2 3 4

Series1Series2Series3

• ApplicationsPresentation Graphics

Surface Graphs

• ApplicationsPresentation Graphics

Pie Charts

• ApplicationsPresentation Graphics

Histogram: A histogram is the graphical version of a able which shows what property of cases fall into each of several or many specified categories.

• ApplicationsPresentation Graphics

Task Scheduling chart: In project management, a schedule consists of a list of a projects terminal elements with intended start and finish dates.

• ApplicationsPresentation Graphics

Production Chart

• ApplicationsPresentation Graphics

Export Chart

• Applications

Computer Art

• ApplicationsComputer Art

Computer graphics are widely used in both fine art and commercial artapplications.

• ApplicationsComputer Art

Fine ArtPaintbrush Program:It allows artists to paint pictures on the screen of a video monitor.

• ApplicationsComputer Art

Example of Paintbrush Methods:

• ApplicationsComputer Art

Commercial ArtLogosPage layout (Combining text and graphics)

• ApplicationsComputer Art

• ApplicationsComputer Art

Commercial ArtMorphing: Where one object is transformed (metamorphosed) into another.

• ApplicationsComputer Art

Commercial ArtMorphing

• Applications

Entertainment

• ApplicationsEntertainment

Computer grap