Games, Movies and Virtual Worlds

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Games, Movies and Virtual Worlds An
Introduction to Computer Graphics

• Ayellet Tal
• Department of Electrical Engineering
• Technion

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When you think about graphics, you envision
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When you think about graphics , you envision
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When you think about graphics, you envision
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Applications

• Science
• Art
• Engineering
• Medicine
• Entertainment
• Advertising
• Education

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Applications

• Science
• Art
• Engineering
• Medicine
• Entertainment
• Advertising
• Education

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Applications

• Science
• Art
• Engineering
• Medicine
• Entertainment
• Advertising
• Education

8
Applications

• Science
• Art
• Engineering
• Medicine
• Entertainment
• Advertising
• Education

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Applications

• Science
• Art
• Engineering
• Medicine
• Entertainment
• Advertising
• Education

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Applications

• Science
• Art
• Engineering
• Medicine
• Entertainment
• Advertising
• Education

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Applications

• Science
• Art
• Engineering
• Medicine
• Entertainment
• Advertising
• Education

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Applications

• Science
• Art
• Engineering
• Medicine
• Entertainment
• Advertising
• Education

Outside-In
http//www.geom.uiuc.edu/docs/outreach/oi/more
graphics.html
http//www.physics.orst.
edu/bulatov/vrml/index.html
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Why interesting?

• The world
• complex
• dynamic
• multi-dimensional continuous

• The screen
• simple
• static
• two-dimensional
• discrete

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Beauty

• Science math and physics
• Engineering software and hardware
• Artistic and aesthetic issues
• Fun!

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Issues in computer graphics

• Geometric modeling
• Rendering
• Animation
• Scientific visualization
  The purpose of computing
  is insight, not numbers
  Hamming
• Virtual reality
• Human-computer interaction

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Geometric modeling

• How do we represent objects?

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Wish list

1. Large domain
2. Unambiguous
3. Unique
4. Accurate
5. Impossible to create invalid representations
6. Easy to create and maintain
7. Closure under certain operations
8. Compact
9. Efficient

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Geometric modeling

• How do we represent objects?

Voxels
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Geometric modeling

• How do we represent objects?

Splines
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Geometric modeling

• How do we represent objects?

Polyhedra
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Rendering

1. What pixels?
2. Whats in the pixel?
3. Which color?

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What pixels scan conversion

• Given A mathematical description of a two or a
  three dimensional scene
• Find A value for each pixel in the frame buffer

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What pixels scan conversion

• Given A mathematical description of a two or a
  three dimensional scene
• Find A value for each pixel in the frame buffer

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Whats in the pixel - visibility

• Goal Hidden surface removal
• In object space or in image space?
• In software or in hardware?

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What color?

• Illumination and shading
• Transparency, reflection

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Issues - recap

• Modeling
• Construct / represent objects
• Transform to construct scene
• Rendering
• Project
• Scan convert
• Remove hidden surface
• Assign colors

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Animation

• How to define / represent complex
  time-dependent behavior of objects?

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(No Transcript)
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Animation topics

• Automatic in-between
• Transformations
• Collision
• Motion
• Facial animation
• Morphing
• Physically-based simulation

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Animation topics

• Automatic in-between
• Transformations
• Collision
• Motion
• Facial animation
• Morphing
• Physically-based simulation

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Animation topics

• Automatic in-between
• Transformations
• Collision
• Motion
• Facial animation
• Morphing
• Physically-based simulation

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Animation topics

• Automatic in-between
• Transformations
• Collision
• Motion
• Facial animation
• Morphing
• Physically-based simulation

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Animation topics

• Automatic in-between
• Transformations
• Collision
• Motion
• Facial animation
• Morphing
• Physically-based simulation

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Animation topics

• Automatic in-between
• Transformations
• Collision
• Motion
• Facial animation
• Morphing
• Physically-based simulation

72 Frames - 5 Full Frames
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Animation topics

• Automatic in-between
• Transformations
• Collision
• Motion
• Facial animation
• Morphing
• Physically-based simulation

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Animation topics

• Automatic in-between
• Transformations
• Collision
• Motion
• Facial animation
• Morphing
• Physically-based simulation

1993, Apple Computer, Inc.
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Case study Teaching dinos to dance
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Algorithm

1. Decomposition
2. Control skeleton extraction
3. Joint binding
4. Motion definition or copying

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Algorithm

1. Decomposition
2. Control skeleton extraction
3. Joint binding
4. Motion definition or copying

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Algorithm

1. Decomposition
2. Control skeleton extraction
3. Joint binding
4. Motion definition or copying

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Algorithm

1. Decomposition
2. Control skeleton extraction
3. Joint binding
4. Motion definition or copying

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Algorithm

1. Decomposition
2. Control skeleton extraction
3. Joint binding
4. Motion definition or copying

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Research topic decomposition

• Let S be an orientable mesh.
• Goal decompose S into connected
  sub-meshes S1, S2 Sk that are face-wise
  disjoint, and whose union gives S.

S1
S2
S
Sk
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Key idea two-phase algorithm

• Find major components with fuzzy boundaries
• Find exact boundaries

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Algorithm outline

• Construct fuzzy decomposition
• Assign distances to pairs of faces
• Assign probabilities of belonging to patches
• Compute a fuzzy decomposition
• 2. Construct exact boundaries

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Algorithm outline

• Construct fuzzy decomposition
• Assign distances to pairs of faces
• Assign probabilities of belonging to patches
• Compute a fuzzy decomposition
• 2. Construct exact boundaries

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Algorithm outline

• Construct fuzzy decomposition
• Assign distances to pairs of faces
• Assign probabilities of belonging to patches
• Compute a fuzzy decomposition
• 2. Construct exact boundaries

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Algorithm outline

• Construct fuzzy decomposition
• Assign distances to pairs of faces
• Assign probabilities of belonging to patches
• Compute a fuzzy decomposition
• 2. Construct exact boundaries

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Algorithm outline

• Construct fuzzy decomposition
• Assign distances to pairs of faces
• Assign probabilities of belonging to patches
• Compute a fuzzy decomposition
• 2. Construct exact boundaries

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Problem finding boundaries

• Given
• G(V,E) the dual graph of the mesh
• A,B,Fuzzy
• Goal Partition V into VA and VB s.t.

A
Fuzzy
B
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Algorithm for finding boundaries

• Assign capacities
• Construct a flow network on Fuzzy
• Find the minimum cut

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The algorithm has

1. Geometry
2. Probability
3. Clustering
4. Graph theory

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Shuttle
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Dove
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Alien
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Camel
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Heart
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Venus
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Skeleton hand
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Skeleton extraction
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Skeleton extraction
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Skeleton extraction
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Skeleton extraction
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Help the dove fly
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So,

• Games, movies and virtual world?

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So,

• Games, movies and virtual world?
• Or
• Modeling, rendering, animations

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So,

• Games, movies and virtual world?
• Or
• Modeling, rendering, animations
• Math, physics, data structures, algorithms,
  software, hardware

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So,

• Games, movies and virtual world?
• Or
• Modeling, rendering, animations
• Math, physics, data structures, algorithms,
  software, hardware
• Science, education, medicine, engineering..

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THE END