An Interactive and Immersive Virtual Environment

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The eScience Wedge

• An Interactive and Immersive Virtual Environment
• A guide to developing applications using the TIWI
  package and utilities

Dr Henry Gardner, Pascal Vuylsteker, David
Walsh, Rod Harris, Hugh Fisher http//escience
.anu.edu.au thewedge_at_escience.anu.edu.au
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Overview

• Hardware features and layout
• The TIWI Interface
• Classpath setup package layout
• Building a simple application
• Java3D scenegraph basics review
• TIWI utilities and advanced features

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Hardware Features

• Stereo optic display ( basic 3D cue )
• Dual screen ( immersion )
• Implies 4 output buffers, 4 x rendering time (
  ?? )
• 8 speaker digital audio ( immersion, 3D )
• Ultrasound head tracker ( immersion )
• and 3Dmouse ( interactivity )
• Domino input device ( navigation, control )
• Microphone ( interactivity )

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Wedge Hardware Layout
Note Microphone
Headtracker and 3Dmouse controllers
not shown
IR signal
IR Emitter
Mirror
Projector
Projector
Monolith serial ports
speakers
1 2
Wedge
bondi
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Remote/local switch
Video (x2)
IR signal
Monitors
Video line splitters
monolith
DAC/ADC DSP
IR signal
Dual 500w amplifiers
Wildcat 4210
Internet
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The Tracked Interactive Wedge Interface

• An API for the Wedge using Java3D
• See http//escience.anu.edu.au/tiwi/src/tiwi.zip
• Not the only way of programming the Wedge
• Includes Demos and utilities
• Easier to setup than straight Java3D
• Same code will run on a POCS
• Has Javadoc documentation
• See http//ephebe.anu.edu.au/tiwi/tiwidoc/

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What the Wedge class gives you

• Class Wedge extends View
• Creates the Virtual Universe, Locale,
  ViewPlatform, Physical Environment and Physical
  Body objects, inter alia, for you
• Physical Environment
• Used to setup input devices (sensors) audio
  output
• Physical Body
• Holds human based parameter, eg height, eye width
  
• ViewPlatform
• One per view, can be placed under arbitrarily
  complex TransformGroup tree

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Building a TIWI Application

• package tutorial
• public class Cube
• public static void main(String args)
• new Cube(1)
• public Cube(int size)
• // set up graphics configuration
• // create a wedge object

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Building a TIWI Application

• package tutorial
• import javax.media.j3d.
• import anu.escience.tiwi.
• public class Cube
• public static void main(String args)
• new Cube(1)
• public Cube(int size)
• // set up graphics configuration
• // create a wedge object

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Building a TIWI Application

• package tutorial
• import javax.media.j3d.
• import anu.escience.tiwi.
• public class Cube
• public static void main(String args)
• new Cube(1)
• public Cube(int size)
• // set up graphics configuration
• WedgeConfigTemplate wct new
  GraphicsConfigTemplate()
• WedgeConfiguration wc new GraphicsConfiguratio
  n(wct)
• // create a wedge object

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Building a TIWI Application

• package tutorial
• import javax.media.j3d.
• import anu.escience.tiwi.
• public class Cube
• public static void main(String args)
• new Cube(1)
• public Cube(int size)
• // set up graphics configuration
• WedgeConfigTemplate wct new
  GraphicsConfigTemplate()
• WedgeConfiguration wc new GraphicsConfiguratio
  n(wct)
• // create a wedge object
• Wedge wedge Wedge.getWedge(wc)

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Building a TIWI Application

• package tutorial
• import javax.media.j3d.
• import anu.escience.tiwi.
• public class Cube
• public static void main(String args)
• new Cube(1)
• public Cube(int size)
• // set up graphics configuration
• WedgeConfigTemplate wct new
  GraphicsConfigTemplate()
• WedgeConfiguration wc new GraphicsConfiguratio
  n(wct)
• // create a wedge object
• Wedge wedge Wedge.getWedge(wc)

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Building a TIWI Application

• package tutorial
• import javax.media.j3d.
• import anu.escience.tiwi.
• public class Cube
• public static void main(String args)
• new Cube(1)
• public Cube(int size)
• // set up graphics configuration
• WedgeConfigTemplate wct new
  GraphicsConfigTemplate()
• WedgeConfiguration wc new GraphicsConfiguratio
  n(wct)
• // create a wedge object
• Wedge wedge Wedge.getWedge(wc)

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Java3D Scene Graph
VirtualUniverse
Locale
BranchGroup
BranchGroup
Transformgroup
Transformgroup
Transformgroup
Transform3D
Box
Shape3D
Transformgroup
Transformgroup
Cone
IndexedFaceSet
BranchGroup
Shape3D
Shape3D
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Homogeneous Coordinates and the Java3D
Transform3D class
Affine Transformations
1 0 0 0 0 1 0 0 0
0 1 0 0 0 0 1

Identity matrix, basic data contained in the
Transform3D class
T1
S1 0 0
R1 R2 R3 R4 R5 R6 R7
R8 R9
T1
T2
0 S2 0
T2
T3
0 0 S3
T3
0 0 0 1
0 0 0 1
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Compound Transformations

• Homogeneous coordinates allow building compound
  transformations by simple matrix multiplication
• Matrix multiplication is associative
• ((AB)C (A(BC))
• But not commutative
• (AB ! BA)
• What does this imply?

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Tiwi Utilities

• Virtual head tracker
• Built in keyboard listener
• Simple 3D mouse cursor
• ANU Loaded Functionality Alpha (AlfAlpha)
• Classpath file finder
• Animation sequence controller and suite of
  interpolators