Graphics 2
06-02408
Level 3
10 credits in Semester 2
Professor Aleš Leonardis
Slides by Professor Ela Claridge
1. INTRODUCTION
The art of 3D graphics is the art of fooling the brain into thinking that it sees a 3D scene painted on a flat screen.
What is computer graphics?
Computer graphics is concerned with the creation and manipulation of graphics images by computer
Creation (modelling)
3D Modelling
Parametric Polygonal
Implicit
2 2 2
2 y z r
x + + =
θ θ 2 4 cos sin
=
= y x
Volumetric
3-dimensional graphics objects created in an abstract object space
Manipulation
• Manipulation of abstract representations of objects and their parts
Individual objects are created and then assembled into final image
TRINITY
Manipulation Manipulation
• Manipulation of graphics objects – Through interactive devices (user) – Application program (hard-wired) – Application program (AI techniques)
• Animation
Graphics images
• Projections of 3-dimensional graphics objects from an abstract object space to a computer screen
• Similar to taking a photograph – locate the object
– compose a view
– record the image on a 2D surface (render)
Graphics images: Viewing and Projection
viewport
3d models camera setup
Graphics images: Camera Positioning
Different views of a 3D model
Projection - a simulation of a simple pinhole camera
http://photo.net/learn/pinhole/frisius.htm
Graphics images: Projection
Representing three dimensions on two dimensional media Vermeer
Graphics images: Rendering
• Display of images on the screen
• Advanced rendering techniques – surfaces
– colours – shading – textures
Graphics images: Rendering: Surfaces
Furnish a 3D wireframe model with a surface
Graphics images: Rendering: Colours
Light and shadow:
colour of different parts of an object suggests its three -dimensional nature
Graphics images: Rendering: Depth Cues
Perspective and Depth of Field
Shadows as depth cues
Highlight/Shadow
Graphics images: Rendering: Texture mapping
http://radoff.com/images/MMOAnatomy3.gif
Graphics images: Rendering: Rasterisation
Although the images are flattened to 2D, depth knowledge is required to order them correctly
Computer
• Hardware and software components specifically designed for graphics
– GPU
– Interactive devices
– Displays and hard-copy devices
3D graphics pipeline
WORLD/SCENE/OBJECT/CONCEPT
3D MODELLING
3D CLIPPING
PROJECTION RASTERIZATION
2D PIXELMAP DISPLAY Modelling coordinates:
- world coordinate system, - object coordinate system
Camera coordinates Screen/Window coordinates Device coordinates
VIEWING
Computer graphics
• Creation and manipulation of graphics images by computer
• Other areas of computing dealing with images – image processing
– computer vision
3D Graphics Applications
• Games
• Entertainment
• Computer Assisted Drafting (CAD)
• Medicine
• Security
• Commerce
Games
• Most recognizable 3D application
• Requires a number of types of skills – Graphics
– Physics – Sound
– Artificial Intelligence (AI) – User Interface (UI)
Entertainment
• Animated movies are a popular form of 3D entertainment
• Combines movement with 3D graphics
• Movement can be achieved through motion capture or avars
– Motion capture – actual person or object performs movements with markers tracked by a video camera – Avar- Animation Variable - a variable that controls object
movement
Virtualized human actions
32
Virtualized human actions Virtual views
Computer Assisted Drafting / Design - CAD
Tools used by engineers and designers to assist in design and documentation of new products
Medicine
Nuclear Medicine
Viewer
Medical applications Medical applications
Medical applications
39
Visualisation
http://blog.tenablesecurity.com/2006/07/3d_tool_screens.html
3D graphic security tool that can help computer system administrators identify weaknesses in network security.
Commerce
• Property
• Business Intelligence
• E-retail
• Maintenance, Training, Documentation
Property
http://www.geosimcities.com/sol_RealEstate.htm
3D graphics can be used by a a user to view a specific location in 3D. Note that the tool displayed here permits the user to navigate through a city in 3D but also has a 2D map displayed as a reference.
Business Intelligence
Business Intelligence is the collection of data, processed into information that managers can use to make business decisions. Displaying data in 3D helps decision makers gain insight into complex relationships.
E-Retail
http://www.virtualshowrooms.co.za http://www.technicon.com/products_demos.html#cf
Modeling environments Virtual(ized) environments
Laser scanning
• Optical triangulation
– Project a single stripe of laser light – Scan it across the surface of the object
– This is a very precise version of structured light scanning Digital Michelangelo Project
http://graphics.stanford.edu/projects/mich/
Source: S. Seitz
Laser scanned models
The Digital Michelangelo Project, Levoy et al.
Source: S. Seitz
Laser scanned models
The Digital Michelangelo Project, Levoy et al.
Source: S. Seitz
Laser scanned models
The Digital Michelangelo Project, Levoy et al.
Source: S. Seitz
Laser scanned models
The Digital Michelangelo Project, Levoy et al.
Source: S. Seitz
Laser scanned models
The Digital Michelangelo Project, Levoy et al.
Source: S. Seitz
Maintenance, Training, Documentation
3D graphical application applied to a practical application of airplane maintenance, training and documentation
3D Graphics Benefits
• Adds realism
• 3D images can help simplify complexity when displaying graphical relations
• User can manipulate object views for a full 360 degree perspective
• Adding a third dimension to data can improve pattern recognition and increase business decision speeds
History
• First use of computer graphics?
History
• 1950
– A CRT tube connected to a computer at MIT to investigate aircraft stability and control.
• early 1950s
– SAGE air-defence system could display crude radar images.
– A light pen used for the first time.
History
• 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 cockpit design, using 3D model of human body.
• First truly interactive graphics system, Sketchpad, pioneered at MIT by Ivan Sutherland for his 1963 Ph.D. thesis
Slide credit: Andries van Dam
Demo: Sketchpad
http://youtu.be/J6UAYZxFwLc
• Hardware revolution
– Moore’s Law: every 12-18 months, computer power improves by factor of 2 in price / performance as feature size shrinks
– Significant advances in commodity graphics chips every 6 months vs. several years for general purpose CPUs
• NVIDIA GTX 680… 3090.4 gigaflops
– Newest processors are 64-bit, 2, 4, 6, 8, or 10 core
• Intel Core i7 – consumer, up to 6 cores hyperthreaded to provide 12 threads
• Intel Sandy Bridge EP– industrial, 8 cores HT, 16 threads
Enabling Modern Computer Graphics
nVidia GeForceTM chip
Slide credit: Andries van Dam
• Graphic subsystems
– Offloads graphics processing from CPU to chip designed for doing graphics operations quickly
– nVidia GeForce™, ATI Radeon™
– GPUs used for special purpose computation, also bunched together to make supercomputers
• GPU has led to development of other dedicated subsystems – Physics: nVidia PhysX PPU (Physics Processing Unit), standard on
many NVIDIA GPUs
– Artificial Intelligence: IBM Watson
• Hardware show and tell: Dept’s new NVIDIA GeForce GTX 460s – 1.35 GHz clock, 1GB memory, 37.8 billion pixels/second fill rate – Old cards: GeForce 7300 GT: 350 MHz clock, 256 MB memory, 2.8
billion fill rate
Enabling Modern Computer Graphics
Slide credit: Andries van Dam
• Input Devices
– Mouse, tablet & stylus, multi-touch, force feedback, and other game controllers (e.g., Wii), scanner, digital camera (images, computer vision), etc.
– Whole body as interaction device:
• http://www.xbox.com/kinect
Enabling Modern Computer Graphics
• Software Improvements – Algorithms and data structures
• Modeling of materials
• Rendering of natural phenomena
• “Acceleration data structures” for ray tracing – Parallelization
• Most operations are embarrassingly parallel: changing value of one pixel is often independent of other pixels – Distributed and Cloud computing
Enabling Modern Computer Graphics
Credits
• These slides contain material from the following sources:
– isg.cs.tcd.ie/dingliaj/notes/MM112_7_Modelling.ppt – mcli.maricopa.edu/files/dvl/3D%20Graphics_v2009.ppt – http://hof.povray.org/
