Computer Systems and Graphics

McGraw-Hill/Irwin ©2008 The McGraw-Hill Companies, All Rights Reserved

Computer SystemsComputer Systems andand

GraphicsGraphics

What is the goal of computer graphics?

• High level, why computer graphics?

• Lower level, what is the computer doing?

Generating Images

• Images are made up of pixels

RGB

RGB Color cube (what we use in computer graphics)

Other color spaces include HSV, YUV, YCrCb, and YIQ

The “goal” of computer graphics

• Solve the function– Red @ a pixel is f(i,j)=…– Green @ a pixel is f(i,j)=…– Blue @ a pixel is f(i,j)=…

Early Applications of Computer Graphics

• Data Visualization– Charts and Graphs

Early Applications of Computer Graphics

• Computer Aided Design (CAD)– Q: Why wireframe?

• Why these apps?– A: Better conceptualization,

interaction, transfer of ideas

Computer Graphics Applications

• Virtual Reality– VR: User interacts and

views with a 3D world using “more natural” means

– Best VR?

• Data Visualization– Scientific, Engineering,

Medical data– Visualizing millions to

billions of data points– See trends– Different schemes

Computer Graphics Applications

• Education and Training– Models of physical,

financial, social systems– Comprehension of

complex systems

• Computer Art– Fine and commercial art– Performance Art– Aesthetic Computing– SIGGRAPH

• Games/Movies

Computer Graphics Applications

• Image Processing– ~Inverse of Graphics– Start with a picture– Process picture

information

• Graphical User Interfaces (GUIs)– WIMP interface– HCI

Overview of Graphics Systems

• Images

• Hardware– Input Systems – Output Systems

• Software– OpenGL

Two Dimensional Images

• Images (at least the ones in this class) are two dimensional shapes.

• The two axes we will label as X (horizontal), and Y (vertical). X Axis

Y

Axis

(0,0) +X

+Y

Hardware Pipeline

Input OutputComputation

We want to draw a rectangle, how do we describe it to a computer?

Model (n) - object description that a computer understands.

Partition the space

(7,3)

(7,9)

(14,3)

(14,9)

Vertex (pl. Vertices) - a point in 2 or 3 dimensional space.

1. Define a set of points (vertices) in 2D space.

2. Given a set of vertices, draw lines between consecutive vertices.

Record every position

Bitmap - a rectangular array of bits mapped one-to-one with pixels.

How do we do this?

Input Devices

• Locator Devices

• Keyboard

• Scanner– Images– Laser

• Cameras (research)

Locator Devices

When queried, locator devices return a position and/or orientation.

•Mouse (2D and 3D)•Trackball•Joystick (2D and 3D)

Locator Devices

When queried, locator devices return a position and/or orientation.

• Tablet• Virtual Reality

Trackers– Data Gloves– Digitizers

Keyboard

• Text input– List boxes, GUI– CAD/CAM– Modeling

• Hard coded– Vertex locations are inserted into code

Scanners• Image Scanners - Flatbed,

etc.– What type of data is

returned? Bitmap

• Laser Scanners - Deltasphere– Emits a laser and does time

of flight. Returns 3D point

• Camera based - research– Examine camera image(s)

and try to figure out vertices from them.

Many others

• Light Pens• Voice Systems• Touch Panels• Camera/Vision

Based• Which is best?

Common Modeling Approach

• Hybrid• Animator jobs

Computation Stage

• Now that we have a model of what we want to draw, what goes on inside the computer to generate the output?

Input OutputComputation

Computation

Transformations Rasterization

Computation Stage

Computation

Transformations Rasterization

Model

Transformed

Model

Output

Displays in Virtual Reality

• Head-Mounted Displays (HMDs)– The display and a position

tracker are attached to the user’s head

• Head-Tracked Displays (HTDs)– Display is stationary, tracker

tracks the user’s head relative to the display.

– Example: CAVE, Workbench, Stereo monitor

3D Glasses

3D Display

3D Object

Graphics Software

• Special purpose software

– AutoCAD– Medical Visualization– Paint– Photoshop

– How about 3D modeling ?

3D Computer Animation

Scientist and engineers used 3-D computer animation to produce graphic representations of the data.

Entertainment industry used computer animation and computer animation become popular.

In 1993, Hollywood released Jurassic Park which captured the public's imagination

What is 3-D Computer Animation?

• Computer animation consists of a series of individual images.

• These images are stored one at a time in the computer. They are viewed at the normal playback speed of 30 frames per second. The result is a moving picture, or animation.

• 3-D animation allows the viewer to move around the scene and change perspective over time. An animator is required to ensure that the animation

looks natural and believable.

Benefits Provided by 3-D Computer Animation

A computer animation can graphically simplify complex concepts which are difficult to visualize.

3-D computer animation captures attention.

It can communicate more information, at a faster rate, than an oral description can.

Best of all, information presented as moving images is retained by the viewer for a longer time and with greater accuracy

Benefits Provided by 3-D Computer Animation

A computer animation can re-create an event which is too expensive or too dangerous to reproduce, such as an aircraft accident.

It can re-create a scene which has been altered or which no longer exists, such as a building which has been demolished.

When used as an illustrative tool, computer animation can help the presenter maintain focus. It creates interesting presentation.

3D Computer Animation Software

Maya the industry standard high-end 3D computer program.

Most of the popular computer games are made with Maya software.

• 3D Studio Max• 3DS MAX

– The world's most popular animation modeling, and rendering solution for film, television, games and design visualization

• Softimage, • Lightwave • Animator Studio

3-D Computer Animation is growing!

• 3-D Computer Animation is the world’s fastest growing creative technology.

• 3-D dominates in the animated feature, game, special effect, interactive, and commercial industry

• Computer 3-D animation is taking over the film world– Computer Animated are breaking box office

records– Computers are used for many of the special

effects in live-action films, and digitized actors.• The field of 3-D animated video, computer,

and interactive games has grown amazingly

Principles of animation

• Animation is not easy. Each second of computer animated video has 30 separate images. The number of images that need to be generated to create even a very short film

Principles of animation

• Modeling: Building objects and creatures from primitive shapes, polygonal modeling, and/or sculpting with curves and points.

• Motion: Animating the objects and creatures you model using key frames, path and shape animation, simulation, deformation.

• Character Construction: Creating skeletons, attaching skins to skeletons.

• Color and Texture: Creating, importing, and applying multiple textures to objects/creatures; defining color, reflectivity, and transparency.

• Rendering: Lights, camera, compiling movies, adding sound.

Jobs: Motion Picture Production & Distribution

• Employment is projected to grow rapidly.

• Employment is centered in several major cities, particularly New York and Los Angeles

• Many workers have formal training, but experience, professionalism, talent, and creativity are the most important factors for getting many jobs in this industry

CAREERS in Computer Animation

• 3D Computer Modeler

• Animator

• Art Director

• Graphic Artist

• Interface Designer

• Multi Media Design Engineer

Some Example of Companies & Computer Animated Films

• PixarThe computer animation at Pixar have been around since 1984– Toy Story, – A Bug's Life– Monsters, Inc– Finding Nemo

• Disney PicturesDisney teamed up with Pixar to create films

• Dreamworks Pixar's main competitor – Shrek

Famous Computer Animated movies

• HARRY POTTER • THE LORD OF THE RINGS• THE MATRIX • MEN IN BLACK• MINORITY REPORT • SCOOBY-DOO • SOLARIS• SPIDER-MAN • STAR WARS

Resource

• Turgut Tezir , 3D Computer Animation• www.cise.ufl.edu/CAP4730: Computational Structures in

Computer Graphics