WEEK 6:Computer Animation Techniques

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WEEK 6Computer Animation Techniques
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Inbetweening

• .

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Slow in/Slow out

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Motion paths

• For eg. We set certain object or camera to follow
  a specific path such as a circular or elliptical
  path
• A 3D trajectory
• Anything can be forced to move along a motion
  path an object, a camera, light or a CV

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Transformation

• Animation based upon the manipulation of
  numbers to produce moving images
• 3 types
• a) scaling
• b) translation
• c) rotation

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Scaling transformation

• The size of an object is dictated by the
  magnitude of the coordinate value ? if we double
  all the numbers representing an objects
  coordinate gtthe objects size effectively doubles
  in all direction
• We could animate an objects size by specifying
  two key frames with different scaling parameters
• By using suitable animation curve gt the size of
  the object would change as the animation moved
  between the two keyframes

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Translation transformation

• Very easy to compute
• Based on additions or subtractions between the
  numbers
• Y

Y
translate
X
X
Z
Z
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Rotation transformation

• Is used to rotate an object about an axis
• Uses a branch of mathematics ? called
  trigonometry(triangles, sines, cosines and
  tangents) to manipulate the X,Y and Z
  coordinates, so they can rotated in space
• The animator has to combine rotations about the
  X,Y, and Z-axes to create complex rotations such
  as a tumble sequence

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• For eg. to create a tumbling object ? the object
  is subjected to a mixture of rotations about its
  local axes
• If an object has to rotate about another object ?
  its rotated about the world frame of reference

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Hierarchical animation

• .

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Hierarchical geometry

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Metamorphosis morphing

• As CVs are altered ? it gives rise to objects
  that change their geometric form
• The method used is to describe the object at
  appropriate keyframes with an animation curve to
  describe the blending process
• See fig 4.19 ? three profile curves formed by
  their respective CVs, which are used to create
  surface or revolution

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Procedural animation
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Forward Inverse kinematics
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Particle systems
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Physical simulation
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Collision detection