WEEK 9: ANIMATION

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WEEK 9 ANIMATION
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Animation Basics

• Animation the modification of any kind of
  object, light, material, or a camera over time
  

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Frame Rates

• The speed at which the images are displayed
• Its measured in frame per second (fps)
• Example. 30fps(high quality animation, not
  flicker), 25fps(best rate for European some
  Asian TV standards)

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• 3D programs usually have a simple timeline/VCR
  control section ? enables the user to select
  particular frame, play back the animation in real
  time

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Keyframing

• To control the animation
• You pose your objects in key positions at
  specific frames (key frames) using a process
  called tweening, the computer calculates the
  objects position for each of the intermediate
  frames ? resulting in smooth motion from one
  post. to the next

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• Example. To animate a ball falling out of the box
  and bouncing on the floor

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Setting Keyframes

• See Figure 9.3

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Keyframe Weighting

• 1.Function curve
• A graphical way of displaying object
  transformation consists of three differently
  coloured splines, each representing different axis

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• Example. If the splines are flat, means no
  activity is occuring on that axis. If the curve,
  the amount they are displaced and their position
  indicates the degree of change on that axis and
  what points in time those changes occur
• See Figure 9.6

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• 2.Pivot Points and Axes
• An object may be transformed around one of
  several axes or pivot points (centers of
  rotation)
  
• The Pivot point can be relocated by choosing a
  Pivot Point command, Center of Rotation command,
  or sthing similar

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Links and Chains

• To create jointed characters, machines, etc you
  need to establish connections between the
  component objects can be done using links
  
• A link a connection between two objects
  animation affecting one also influences the other

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• The first object is called the parent, movement
  applied to it, is transferred to the second
  object - child

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• A chain a series of linked objects it uses the
  same parent-child relationship, but extends it to
  grandchild, great-grandchild, and so forth

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Parent
Child
Child
Child
Grandchild
Grandchild
Grandchild
Graphical representation of the hierarchical tree
structure of potential links
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Nulls (or dummy objects)

• Can be used as invisible components of a chain OR
  as invisible objects provide a pivot point to
  orbit other objects around
  
• Usually appears as cubes or other simple objects

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• Establishing a null/dummy object as parent in a
  complex chain makes it easier to select and
  transform the objects linked to it
  
• Example. Kamov KA-27 helicopter requires two
  null objects

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Bone Deformation

• The technique of animating an object (character)
  by defining and animating an internal skeleton
  that automatically deforms the surrounding mesh
  
• Example. Figure 9.11 By moving the bones, the
  mesh will move as well

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Forward and Inverse Kinematics

• Forward Kinematics (FK)
• Default method of animating linked objects
• The movement of the parent object affects all the
  offspring on down the chain

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• Example. If you move the parent, the children
  move too, if you rotate the parent, you will
  rotate the children
  
• Using FK to make the end of an arm-like bone
  hierarchy to touch a particular spot requires
  individual adjustment of each bone, one at a
  time, often requires multiple passes to achieve
  it

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• Inverse Kinematics (IK)
• Method of controlling linked objects by moving
  the very end of the chain and having the rest of
  it adjust to compensate

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• Enables the user to move the end of the same
  arm-like bone hierarchy directly to the desired
  spot ? the bones rotate automatically to keep the
  chain in one piece
• See Figure 9.13

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Morphing

• A technique that enables you to make smooth
  changes to an objects shape by copying the base
  (original) mesh and modifying it into a different
  shape or morph target
• Morphs can turn any form into another

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• Can be used to animate organic forms
  realistically, such as a persons facial
  expressions and speech ( Figure 9.14)
  
• Example. The transformation of the liquid metal
  T-1000 in Terminator 2

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Particle Systems

• 3D animation modules that enable you to generate
  and control the behaviour of a vast number of
  tiny objects
  
• Can be used to simulate natural effects water,
  fire, sparks, bubbles, smoke, etc

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• Can also be used to create a flocking effect for
  animating groups of birds, butterflies, bees,
  fish, etc
  
• Example. The solar flare and luminous gas cloud
  in the opening of Star Trek Voyager

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• Example. A particle system waterfall. Particle
  system can interact with mesh in the scene and
  can be affected by forces such as wind,
  turbulence, or gravity

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Scripted Animation

• Controls objects or parameters in the scene
  without hands-on attention from the animator
  
• Is controlled by a text script written in a
  program-specific scripting language

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• 1. MAXScript 3ds max
• 2. LScript - LightWave
• 3. MEL - Maya

You write a program to control the animation
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• Scripting enables an animator to create motion
  that is mathematically precise of that would be
  difficult and time consuming to do by hand
  (manually)