General Overview

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General Overview
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General Overview
Why physics ?

• Because most things in our everyday
• environment can be described by physics
• and a common ambition in a simulation
• is to describe an environment
• Physical simulations capture complexity
• Complex behavior emerges from simulation

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General Overview
Luxo Jr. by John Lasseter, Pixar 1987

• Keyframed realistic animation with no
• physical simulation.
• Still, physics does the trick
• High level motion control Jump from A to B
• Luxo Jr. made people start thinking about
  physics . . .

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General Overview
Physics is . . .

• Systematic
• Scalable
• Consequent
• Controllable
• Extensible
• General

Therefore library software and expertise can
evolve !
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General Overview
Applying Physics can create . . .

• Dynamics (Newtons Laws)
• Rigid Body Dynamics, Interaction, Collisions
• Mechanics of Materials
• Fluids, water (water, yacht)
• Gases, smoke, clouds (smoke, train, interactive,
  clouds)
• Plasmas, fire, lightning, sparks (candle)
• Particles (special effects, explosions,
  fountain, hair, fur)
• Fields
• Body interaction
• Collective phenomena, complex systems,
  emergence,
• Audio wave tracing, acoustics, damping,
• Light optics, ray tracing,
• Effectors and sensors display and interaction

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In the Beginning . . .
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In the Beginning . . .

• Computers were hulking Goliaths locked in
  air-conditioned
• rooms.
• But a young electrical engineer and former naval
  radar
• technician named Douglas Engelbart viewed them
  differently.
• Engelbart envisioned them as tools for digital
  display.
• He knew from his days with radar that
• any digital information could be viewed
• on a screen. Why not, he then reasoned,
• connect the computer to a screen and
• use both to solve problems?

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In the Beginning . . .

• Engelbart's ideas were dismissed, but by the
  early 1960s other
• people were thinking the same way.
• Moreover, the time was right for his vision of
  computing.
• Communications technology was intersecting with
  computing
• and graphics technology.
• This synergy yielded more user-friendly
• computers, which laid the groundwork for
• personal computers, computer graphics,
• and later simulations.

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In the Beginning . . .
Pivotal Points in History . . .

• Fear of nuclear attack prompted the U.S.
  military to commission a new radar system that
  would process large amounts of information and
  immediately display it in a form that humans
  could readily understand. The resulting radar
  defense system was the first "real time," or
  instantaneous, simulation of data.
• Aircraft designers began experimenting with ways
  for computers to graphically display, or model,
  air flow data.
• Computer experts began restructuring computers
  so they would display these models as well as
  compute them. The designers' work paved the way
  for scientific visualization, an advanced form of
  computer modeling that expresses multiple sets of
  data as images and simulations.

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In the Beginning . . .
More Pivotal Points in History . . .

• One of the most influential antecedents of
  todays simulations was the flight simulator.
  Following World War II and through the 1990s, the
  military and industrial complex pumped millions
  of dollars into technology to simulate flying
  airplanes (and later driving tanks and steering
  ships).
• By the 1970s, computer-generated graphics
• had replaced videos and models. These
• flight simulations were operating in
• real time, though the graphics were
• primitive. By the early 1980s, better
• software, hardware, and motion-control
• platforms enabled pilots to navigate
• through highly detailed virtual worlds.

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In the Beginning . . .
Even More Pivotal Points History . . .

• Of course, the "military-industrial complex" was
  not the only entity interested in computer
  graphics.
• A natural consumer of computer graphics was the
  entertainment industry, which, like the military
  and industry, was the source of many valuable
  spin-offs in virtual reality.
• By the 1970s, some of Hollywood's most dazzling
  special effects were computer-generated, such as
  the battle scenes in the big-budget, blockbuster
  science fiction movie Star Wars, which was
  released in 1976. Later came such movies as
  Terminator and Jurassic Park. In the early 1980s,
  the video game business boomed.

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Engineering Techniques and Feats in Physics
Simulation
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Current Climate

• Physics-based simulation is the art of reducing
  algorithmic complexity to achieve usable results
  with as little computation as possible.
• Current visualizations usually incorporate both
  scientific simulations based on research data and
  parametric rule-sets that augment the data and
  save time.
• State of the art simulation technology in this
  field is most often proprietary and created by
  specialized teams (scientists, engineers,
  artists, specialists) when the need for them
  arises.
• A large amount of cooperation between research
  institutions, productions houses, and software
  developers is needed and planning for
  computational demands is highly coordinated.

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Current Climate
Some General Approaches Used

• System Modeling (pre-computed) Simulation
  based on equations (x,y,z,t) that are computed
  for individual data points (the more the better).
• Parametric Rule-Sets (pre-computed) Integrates
  pre-computed systems with other simulations (from
  artists or augmented and reduced systems) based
  on defined parameters.
• Selective Data Plotting (real-time) Compute
  only the data points you need to get an accurate
  representation of your system. Example
  Ray-casting
• Monte Carlo Simulation (depends on application)
  Compute complex systems using algorithms with
  reduced complexity by guessing (using known
  boundaries).

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Current Climate
Areas Where Simulations Are Used in the Industry

• Newtonian Physics - Rigid Body Kinetics, Object
  Collisions, etc.
• Realistic Human Movement Muscle Behavior,
  Skeleton Behavior, etc.
• Volumetric Rendering Natural Phenomenon (fire,
  smoke, clouds, fluids, solid bodies)
• Large-Scale Simulations Flocking, Group
  Behavior, and Character Interaction

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Newtonian Physics

• Newest
• implementation
• allows user control
• over bodies.
• Basic laws of Newtonian physics are readily
  defined
• (ex a(t) v(t) s(t)).
• Uses algorithms with interpolate the appropriate
  physical simulation based on user-defined actions
  (similar to key-framing).
• Current hurdles involve number of bodies, which
  can interact in real-time, and how many
  parameters are checked for each instance of time.
• Research at Carnegie Mellon University and
  implementation using controller packages like
  Maya, Houdini, and Softimage.

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Realistic Human Movement

• A new technique is being developed at the
  University of Toronto that creates a composable
  controller system for human movement.
• It links motor abilities of characters to
  physics-based controllers.
• This is different from traditional character
  animation because character responds to
  interactions based on laws of physics.
• This is done through the groups of linked
  controllers that contain physical parameters.

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Volumetric Rendering

• This technique has been too computationally
  intensive (usually N3 complexity) in the past.
• In the last couple of years new technologies and
  techniques have arisen to reduce the complexity.
• Ray-casting This method computes only the
  portions of the volume that are seen given the
  current projection.
• Volumetric models of systems are
• important because they are
• easily integrated with both
• pre-computed system model data
• and parametric rule-sets to create
• realistic behavior.

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Volumetric Technologies

• Arete Digital Nature tools used in Cinema.
  Creates volumetric fluids, clouds, etc.
• Real-time volumetric renderings can still not be
  computed accurately on standard computer hardware
  without an additional accelerator.
• Mitsubishi Electronics RTViz group produced to
  VolumePro 500 and VolumePro 1000 to do
  ray-casting in real-time.
• Uses a large frame buffer and specialized
  hardware
• to compute 2563 individual volumes at 30 fps.
• Nvidia developed a technology (VTC) that
• compresses 3D textures (representing slices of a
• volumetric object).

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Large Scale Simulation
Particles and Flocking

• Uses a large number of discrete objects (with
  physical parameters and or simulation data
  attached) to model systems in which many bodies
  are interacting non-uniformly.
• Examples are crowds, swarms, and flocks, which
  could represent characters or environmental
  phenomenon.
• Large-scale simulations are usually coupled with
  other technologies such a volumetric rendering
  and Newtonian physics.
• Wetas Massive is a very advanced, state of the
  art implementation of large-scale simulation.

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Current Feats
LOTR Two Towers

• Weta used its proprietary software
• Massive for large-scale simulation.
• It integrated Massive with its own
• physics-based muscle-system using
• Maya to create effects that would take
• 460 years to be rendered on a home PC.
• Rendering and simulation took 10 months and was
  done using about 1000 IBM and SGI workstations.
• Their own rendering and shading program Grunt
  was used with Massive to aid in simulating cloth
  and hair on individual characters in the crowd.

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Recent Feats
A Perfect Storm

• First film where ILM feels they created
  realistic fluid dynamics.
• Until recently, fluid flow simulations could
  only be run with 80-100 data points. In A
  Perfect Storm simulations of several different
  oceans were run in 3D using a much larger data
  set and various parameters until they looked
  right.
• Several simulation technologies went into
  recreating the ocean.

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Simulating Physics in the Art World
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Simulation for the Artist
Ability to manipulate/distort physics of their
digital environment
Game Designer Perspective

• Games allow Player to express himself
• Realism is not necessarily the goal for games
• Simulated World that has Consistently

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Simulation for the Artist
Grenade example grenade bounces realistically
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Simulation for the Artist
Pros of digital simulation

• Time Saved Reduced costs
• Emergence new strategies and
• game play by user
• Simulated World that has Consistency
• New and more genres of games created

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Simulation for the Artist
Cons of digital simulation

• Unexpected methods of game play by player
• Being too complex or real for the game
• More user feedback is required
• Hardware limitations reduces use or ability
• Deeper simulation does not mean more fun.
• Maybe just more interesting

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Simulation for the Artist
Thief by Looking Glass Studios
Deeper awareness model with complex sound
propagation and lighting used for stimuli of
characters
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Simulation for the Artist
Thief by Looking Glass Studios
Sound simulated to bounce off surfaces and
materials with varied intensity and reverb.
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Simulation for the Artist
Thief by Looking Glass Studios
Designers added a light gem feedback device To
help the player utilize environments effectively
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Simulation for the Artist
Simulation to the non-Game Artist
3D programs like Maya 3D incorporate more
simulation for manipulating and controlling
physics in 3D.
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Simulation for the Artist
Simulation to the non-Game Artist
KPT makes Adobe Photoshop plug-ins utilize 3D
physics simulation of light movement upon 2D
surfaces.
Ex. Goo Gel Materizlier Turbulence
original
Goo plug-in
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What Simulation means to the Public
What the General Public will see

• Simulation-based game design produce
• more variable player driven game play
• More dynamic effects in movies produced with
  digital tools

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Movie Industry Example
LOTR Used motion-capturing to create cycles
to be used with AI and physics to simulate
mass warfare.
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Future of Virtual Simulation and Visualization
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Future of Virtual Simulation and Visualization

• Current problems that keep our technology from
  advancing
• Overcoming technological barriers and what to
  expect from future simulation
• Real-time simulation and visualization
• Advancements in representing human figures in
  motion
• Realistic walking movement
• Physics-based human simulation for virtual
  prototyping
• Human populations in simulations
• Technology that can be used for motion planning
  in robots

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Future of Virtual Simulation and Visualization

• Problems that keep our
• Simulation technology from advancing
• Todays simulations require intense computational
  resources
• Most simulations generate gigabytes to terabytes
  of data, whether it is a scientific application
  or an artistic application such as movie effects
• This Data requires not only huge amounts of
  storage space but also the computer processing
  power to handle it.

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Future of Virtual Simulation and Visualization
Example of a movie simulation Water When
simulating water, dynamics and large scale 3D
grids are used. Each point on the grid can
generate thousands to millions of particles that
are tracked over time.
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Future of Virtual Simulation and Visualization
Example of a movie simulation Water The amount
of data generated is so immense that in many
cases artists must manually add in details
because the movie production can not afford so
much simulation time.
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Future of Virtual Simulation and Visualization

• Overcoming technological barriers and what to
  expect from future simulation
• As computers get faster and storage space becomes
  cheaper, more complex and realistic
  visualizations are possible
• Real time visualization will revolutionize the
  world of simulation.

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Future of Virtual Simulation and Visualization

• Real time means that the graphical outcome of a
  simulation will be available as the computer
  works through the simulation.
• What does this mean for artists?
• Artists will be able to create very complex
  visuals without waiting to see the final product.
  Changes will be possible without the fear of
  long rendering times.

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Future of Virtual Simulation and Visualization

• What does this mean for scientists?
• Scientists will be able to simultaneously get
  data from the simulation while analyzing the
  computer visualization.

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Future of Virtual Simulation and Visualization

• How far have we come with real time?
• Pixars first film, Luxo, Jr. was made almost
  17 years ago. The short film was rendered on a
  Cray supercomputer that took 75 hours per second
  of animation.
• Future animated
• films could be done entirely
• on desktop machines as
• hardware advances.

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Future of Virtual Simulation and Visualization
Advancements in representing human figures in
motion Research is being done to develop systems
to more realistically display human movement such
as walking. Todays systems pass for situations
not intended to be realistic but when actual
human-like figures are represented, we can notice
that there is something not right. Physics are
what control human movement. The combination of
physics and other techniques such as motion
capturing can yield very realistic human motion.
There is still a lot to hope for.
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Future of Virtual Simulation and Visualization
Final Fantasy uses CG to represent Humans
Squares Final Fantasy The Spirits Within raised
the bar for technical achievement as it made
digital actors look realistic.
Characters moved almost too gracefully as real
humans tend to be somewhat more jerky and
unpredictable. We can expect to see much more
realistic movement in future CG movies.
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Future of Virtual Simulation and Visualization
Future Applications of Realistic Human
Motion Physics-based Human Simulation for
Virtual Prototyping Boston Dynamics has been
developing a landmark 3D software product for
real time simulations called DI-Guy. This
software adds artificial human life to
simulations such as virtual battlefields.
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Future of Virtual Simulation and Visualization
Future Applications of Realistic Human
Motion Technology for Virtual Humans could
provide potential for humanoid robots. Robots
use complex physics to perform simple motion. In
the next 10 years, Humanoid robots could be a
common sight. The development of these
new robots could be furthered by the same
research done to represent human movement
graphically.