WEEK 11: COMPUTER ANIMATION SOFTWARE

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WEEK 11 COMPUTER ANIMATION SOFTWARE HARDWARE
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1. Hardware

• 1. Refresh rate
• Define how often the display screen is refreshed
  with an image ? same or new image
• Image ? composed of 2 parts called field

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• 1. Consists of the odd rasters
• 2. Even rasters
• Interlacing
• 2 fields ? formed by CRT(Cathode Ray Tube)

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• Interlacing the odd fld, followed by even fld ?
  keeps the image refreshed
• Reasons
• 1. To min the freq bandwidth of the
• broadcast signal
• 2. To reduce flicker, by maximizing the
• refresh rate

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Table 11.1 Field and frame rate for the USA and UK
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• Most computer monitors non-interlaced, entire
  frame refreshed at a speed that cause min flicker

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• 2. Update rate
• Rate at which the content of the image is updated
• Equals to refresh rate(in video rate)
• In computer update rate determined by the speed
  at which software executed.

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• E.g., if a computer can execute renderer program
  at 10Hz ? only 10 different images seen every
  sec, computer still attempt to refresh at the
  screen at its refresh rate

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Hardware - Computer

• Come in all shapes and sizes humble PC to
  massively parallel supercomputer
• Today, all computers are able to create pictures,
  used as computer animation platform

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• Every computer has processing limitations ?
  dictates the complexity of 3D images it can
  manipulate

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• PC
• Most PCs equipped with graphic facility to
  support multimedia applications, display of 2D
  and 3D graphics
• High-performance graphics boards are required to
  support realistic rendering time

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• Graphics boards will include the following
  characteristics
• - range of resolution
• - large on-board texture memory
• - perspective correct texture memory
• - sub-pixel and sub-texel positioning
• - texture morphing

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Cont

• - Gouraud modulated textures
• - video texture mapping
• - anti-aliasing
• - number of textured triangles rendered
• per second
• - per-pixel fog, smoke and haze effects

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• Rendering speeds ? measure in terms of how many
  pixels can be written per second or millions of
  textured triangles per seconds most boards are
  currently exceeding a fill rate of 100
  mega-pixels per second and exceeding 5 million
  triangles per second

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• A PC also comes with more than one processor ? it
  can execute 2 parts of a program in parallel
• Software can only take adv of this feature, if it
  has been designed with a multi-threading facility

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• Graphics workstations
• Have always played important role in supporting
  computer animation
• Operate with a UNIX or LINUX operating system
  UNIX and LINUX provide an ideal environment for
  developing software, i.e. develop code

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• Supercomputer
• Generally manufactured by Silicon Graphics, Inc.
  ? used for high-end computer applications
• They are used because of the superior rendering
  speeds, often measured in tens of million of
  triangles per second

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Motion capture

• To capture the motion of humans
• Used in computer animation and some for VR
  systems
• In computer animation, character animation is
  difficult, although it can be done via scripting
  and keyframe animation

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• The technologies currently available include
  mechanical, optical, ultrasonic and magnetic

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1. Software

• You can run your animation system on a UNIX or
  LINUX workstation, an NT PC, 2000 PC, or an Apple
  MAC
• Not every software product is available on these
  platforms

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• Today animation systems include products such as
• - Maya
• - SoftImage
• - Houdini
• - 3D Studio MAX
• - Lightwave
• - Sumatra

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• They vary in price as well as features
• Some of the areas you need to investigate
• - overall user interface
• - ease with which you can move from
• modeling, to animating and rendering
• - ease of modeling
• - ease of using NURBS

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Cont

• - the way particles are incorporated
• - library of texture maps
• - the image quality of the renderer
• - anti-aliasing
• - bump mapping
• - quality of shadow
• - animation editor
• - keyframing tools
• - scripting facility

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• - expressions interface
• - interface for inverse kinematics
• - ease of building skeleton
• - range of shaders
• - range of plug-ins
• - help facility
• - collision detection
• - different resolutions
• - selective rendering
• - etc