VRML in Virtual Environments

1
VRML in Virtual Environments

• CS-4473 Virtual World Simulation
• David Laflam
• March 14 2000

2
Objectives

• To provide a general overview of Virtual
  Reality Modeling Language (VRML) and its
  application in a Virtual World and Simulation.
• To demonstrate a scene graph tool that uses VRML

3
Outline

• History (Past, Present, Future)
• VRML Terminology
• Node, File, Events, Routes
• Naming Conventions
• Syntax
• Commercial uses of VRML
• CAVE (Cave Automatic Environment)
• References

4
History (Past, Present, Future)

• May 1994 International Conference WWW
• Mark Pesce and Tony Parisi presented Labyrinth
  Program
• SGI offers Open Inventor format VRML 1.0
  Official May 26 1995
• VRML 97 (Spec was sent to ISO)
• VRML 2.0 (ISO Standard)
• WEB3D (Future Standard)

5
Web3D ISO Roadmap
6
VRML Development

• VRML Roots
• Inventor from Silicon Graphics (Open Inventor)
• Provide an easy to use, scene structure, object
  description based on Open Inventor format a
  scene-description language to use on the Web
• VRML 1.0 (October 1994)
• Goal to create static 3D worlds links
• VRML 2.0 (August 1996)
• objects move
• objects can respond to events
• use multimedia objects (sound, video)

7
VRML 2.0 Features

• The goal of VRML 2.0 is to provide a richer, more
  exciting, more interactive user experience than
  the static boundaries of VRML 1.0.
• The second goal is to provide a solid foundation
  for future VRML expansion, to keep things as
  simple and as fast as possible for everyone
  (browser developers, world designers, end users).
• Enhanced static worlds
• (ground/sky colors, fog, irregular terrain,
  sound, )
• Interaction
• (Sensors, collision detection, )
• Animation
• (Interpolators, )
• Scripting
• (a scripting takes input from sensors and
  generates events based on that input which can
  change other nodes in the world).
• Prototyping
• ( a prototype -- a new node type instances,
  parameter interface )

8
Changes from VRML 1.0

• New Node Types
• Group nodes (Collision, Transform)
• Browser Information (Background,NavigationInfo,
  Viewpoint, WorldInfo)
• Lights and Lighting (fog)
• Sound
• Shapes (geometry nodes property nodes)
• Geometry (ElevationGrid, Extrusion, Text)
• Appearance

9
Changes from VRML 1.0

• Sensors
• (TouchSensor, CylinderSensor, PlaneSensor,
  SphereSensor, )
• Special Nodes
• (Scripting, Interpolators, )
• Deleted Node Types
• AsciiText --gt Text (non-English)
• Info --gt WorldInfo
• PerspectiveCamera --gt Viewpoint
• Separator --gt Transform
• Transformation nodes --gt Transform

10
Features of VRML

• Interactivity
• VRML worlds respond to the viewers actions
• Animation
• Objects move, and humanoid avatars walk, run, and
  jump.
• Audio
• VRML provides support for background music,
  ambient noise, and fully spatialized stereo
  sound.
• Scripts
• VRML allows you to include programs for more
  advanced control of animation and user
  interaction
• Prototyping
• Code reuse

11
VRML Challenges

• Browsers compliance, consistency, performance
  (plug in problems)
• Authoring Tools are poorly suited to VRML 2.0's
  demands
• Modeling packages for offline rendering generate
  too many polygons (Chisel Program polygon
  reduction tool)
• Animation packages don't understand VRML's
  event-driven model
• Optimization tools are few and far between
• Complex, open file format makes proprietary tools
  difficult to integrate
• Workflow difficult one way export/import isn't
  good enough

12
Open source

• Crucial part of our VRML/X3D strategy
• Java
• Sun commitment of Java3D code, time
• VRML 97 and X3D loaders available
• C
• multiple source bases becoming available
• nVidia, others
• CosmoPlayer status

?
13
VRML Terminology

• Nodes and Fields
• Name Scoping
• Defining and Reusing
• Events and Routes
• Time-Dependent Nodes
• General VR Concepts
• Non Immerse VR
• Immerse VR
• Presence

14
Naming Conventions

• Node Names Begin each word in the name with a
  capital letter
• Example
• CylinderSensor, Transform, IndexFaceSet
• Field Names Same as node name except the first
  word uses lower case
• Example (field and exposedField)
• translation, cycleTime

15
Defining and Reusing

• DEF allows you to define a node
• DEF node-name node-type ..
• appearance DEF Brown Appearance material
  Material diffuseColor 0.6 0.4 0.0
• USE allows you to call a defined node
• USE node-name
• appearance USE Brown

16
Syntax

• used for VRML Comments
• VRML Header
• each VRML file must begin with VRML V2.0 utf8
• UTF8 is the UCS Transform Format, and UCS is the
  Universal Character Set, it is defined by ISO
  10646-11993
• Nested format
• Facilitates parent child format

17
Reserved Words

• Reserved Words in VRML are
• DEF, EXTERPROTO, FALSE, IS, NULL, PROTO,
• ROUTE, TO, TRUE, USE,eventIn, eventOut,
  exposedField, field

18
Coordinate Spaces

• VRML objects are considered to exist in a 3D
  virtual Space with locations descried in
  rectangular(X,Y,Z) coordinates relative to an
  arbitrary (0, 0, 0).
• Positive Y (up), Positive X(left), Negative Z
  (into the monitor).
• Measured in Radian and Meters

19
Nodes

• The basic unit of a VRML File is a node.
• The type of node is required
• A set of curly braces required
• Some number of fields (optional) and their values
  that define the attributes of the nodes with in
  the curly braces.

20
Nodes

• Example
• Shape
• appearance NULL exposedField SFNode
• geometry NULL exposedField SFNode
• This is a shape node with appearance and
  geometry fields

21
Field Value Types

• SFBool Boolean True /False
• SFColor/MFColor 3 floating point to describe
  color
• SFFloat/MFFloat Used to describe HT and Radius
• SFImage List of values describing
  the colors of digital picture
• SFInt32/MFInt32 32bit integer values
• SFNode/MFNode A VRML node
• SFRotation/MFRotation To Specify how to orient a
  shape
• SFString/MFString To specify a list of
  characters
• SFTime For animation Start Time/End Time
• SFVec2f/MFVec2f 2D Floating Point Vector
• SFVec3f/SFVec3f 3D Floating Point Vector
• SF - Single Value Type , MF - Multiple Value
  Type

22
VRML Node Types

• 7 Types of nodes
• Geometry and Geometry Support Nodes
• Appearance Nodes
• Grouping Nodes
• Animation and Behavior Nodes
• Sensors
• Environmental Nodes
• Navigation-Related Nodes

23
Geometry Nodes

• Geometry and Geometry Support Nodes represent
  geometry in the VRML world ( and provide
  necessary data for defining that geometry)
• Node Type
• Box , Cone, Cylinder, ElevationGrid, Extrusion,
  IndexFaceSet, IndexLineSet, PointSet,Shape,
  Sphere, Text, Coordinate.

24
Geometry Nodes

• Code
• VRML V2.0 utf8
• Shape
• geometry Cylinder
• height 2.0
• radius 2.0
• Cylinder1.wrl

25
Appearance Nodes

• Appearance Nodes are used in determining how a
  piece of geometry looks.
• Node Types
• Appearance, Material, Color, Normal,
  ImageTexture, MoiveTexture, PixelTexture,TextureTr
  ansform, TextureCCoordinate, FontStyle

26
Appearance Nodes

• Code
• VRML V2.0 utf8
• Draw the hut walls
• Shape
• appearance DEF Brown Appearance
• material Material
• diffuseColor 0.4 0.6 0.0
• geometry Cylinder
• height 2.0
• radius 2.0
• Cylinder2.wrl

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Appearance Nodes

• Code
• VRML V2.0 utf8
• Shape
• appearance Appearance
• material Material
• geometry Text
• fontStyle FontStyle
• family "SERIF"
• style "BOLD
• TEXT.wrl

28
Grouping Nodes

• Grouping Nodes collect other nodes together, the
  parts to the whole.
• Node Types
• Transform, Group,Collision,Billboard,Inline,
• string "Hello Class"
• LOD (Level of Detail), Switch

29
Grouping Nodes

• Code
• VRML V2.0 utf8
• Group children
• Draw the hut walls
• Shape appearance DEF Brown
  Appearance
• material Material
  diffuseColor 0.4 0.6 0.0
• geometry Cylinder height 2.0
  radius 2.0 ,
• Draw the hut roof
• Transform
• translation 0.0 2.0 0.0
• children Shape
• appearance USE Brown
• geometry Cone
• height 2.0
• bottomRadius 2.5
  
• Cylinder3.wrl

30
Animation/ Behavior Nodes

• Animation/ Behavior Nodes provide support for
  animation, sound, and other time-based activity,
  as well as programed behaviors
• Node Types
• TimeSensors, ColorInterpolator,
  CoordinateInterpolator, NormalInterpolator,
  PostionInterpolator, ScalarInterpolator,
  OrientationInterpolator, Script

31
Animation/ Behavior Nodes

• Code Example
• See attached page for planet code
• Animation1.wrl

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Animation/ Behavior Nodes

• Code Example
• See attached page for planet code
• ScalarInterpolator Demo
• Will use an Example for thesis
• Animation3.wrl

33
Sensors

• Sensors detect viewer motion and actions, or
  nodes that react to users interaction
• Node Types
• CylinderSensor, PlaneSensor, ProximitySensor,
  SphereSensor, TouchSensor, VisibilitySensor
• TouchSensor senses a click
• ProximitySensor senses a distance
• PlaneSensor senses a drag action
• TimeSensor senses a time tick
• (it can be triggered by other sensors)

34
Sensors

• Code Example
• See attached page for TouchSensor code
• touch.wrl

35
Environmental Nodes

• Environmental Nodes distribute effects over an
  area, not tied to a particular piece of geometry
• Node Types
• DirectionalLight, PointLight, SpotLight, Sound,
  AudioClip, Background, Fog, WorldInfo

36
Environmental Nodes

• Example Code for FOG
• VRML V2.0 utf8
• Group
• children
• Fog
• color 1.0 1.0 1.0
• fogType "LINEAR"
• visibilityRange 20.0 ,
• Background skyColor 1.0 1.0 1.0 ,
• Inline url "fogworld.wrl"
• FogExample.wrl

37
Environmental Nodes

• Example Code for Lighting
• See Attached Handout
• Lighting.wrl

38
Navigation-Related Nodes

• Navigation-Related Nodes affect the viewers
  navigation through the world or scene
• Node Type
• Viewpoint, NavigationInfo, Achor

39
Navigation-Related Nodes

• VRML V2.0 utf8
• Group
• children Viewpoint
• description "60.0 FOV degree corner
  view"
• position 3.0 1.6 3.0
• orientation 0.0 1.0 0.0 0.611
• fieldOfView 1.047
• ,
• NavigationInfo
• type "WALK"
• speed 1.0
• headlight TRUE
• avatarSize 0.5, 1.6, 0.5
• ,
• Inline url "DaveSub3.wrl"
• DaveSub3.wrl

40
Events and Routes

• Events provide the wiring instructions for the
  VRML scene, like the use of mouse to turn on
  light, or trigger a sound.
• The wring involves
• A pair of nodes to wire together
• A wiring route, or path, between the nodes
• Events
• A message that is passed between nodes with
  eventIn or eventOut.

41
Events

• Collision Node example
• Collision
• children exposedField MFNode
• proxy NULL field SFNode
• addChildren eventIn MFNode
• removeChildren eventIn MFNode
• collideTime eventOut SFTime
• Node Field Type Field Type
  of Field Value

42
Routes

• Routes describe a circuit from one nodes
  eventOut to another nodes eventIn. The circuit
  route remains domant until an event is sent from
  the first node to the second node until the route
  ends.
• The type of reaction depends on
• The type of node receiving the event
• The node input jack to which the route is wired
• The values contained in the event
• The current activities of the node

43
Subdivide large VRML files

• Download Time A single monolithic file is
  inefficient user cannot interact until download
  is complete (like Shockwave) maximum memory use
  and decompress time
• Reuse Subdivision allows Reuse and nesting of
  subfiles
• Scalability Subdivision allows very large
  worlds
• Single file makes unloading parts of the world
  impossible
• Hinting Subdivision enables browser
  optimizations
• Enable "trickle" downloading whenever possible
• Think about Inlining anything which is a
  candidate for LOD'ing Insides of houses in a
  town, contents of refrigerator

44
Scene Graph

• Scene Graph
• the relationship between objects in the scene and
  the way those objects interact with each other.
  It provides for a graph like structure to
  visualize this relationship.
• VRML Scene Graph
• All nodes have a relationships (senior to
  subordinate)
• Group
• Viewpoint
• Navigation
• Shape
• Sphere
• Material

45
Scene Graph Demo
VRML Scene Graph is the relationship between
objects in the scene and the way those objects
interact with each other. It provides for a
graph like structure to visualize this
relationship.
46
Java / VRML

• VRML actions are controlled with the use of a
  script node
• Script
• url exposedField MFString
• mustEvaluate FALSE field SFBool
• directOuput FALSE field SFBool
• Any number of
• field fieldType FieldName intailValue
• eventIn eventInType eventInName
• eventOut eventOutType eventOutName

47
Java / VRML

• In Java, the API provides the getBrowers method
  of the Script class. The return object is an
  instance of the Browser class, which provides
  methods for
• Querying the browser
• Changing world content
• Reading a new world
• In JavaScript program script, the API provides an
  automatically created browser object.
• Provides same functionality as above

48
Java / VRML

• This defines a java script that has an eventIn as
  a SFFloat called set_fraction ,and has an
  eventOut of a SFVec3f called value_changed
• Demo Ripple.wrl

• DEF Mover Script
• urlmove1.js
• eventIn SFFloat set_fraction
• eventOut SFVec3f value_changed

49
Proto and Externproto

• Proto
• Defines a new node type that is local to the VRML
  File
• Externproto
• Defines a new node type that is external to the
  VRML File.
• This is used in the case of a library of new node
  types
• An example pipes proto from NIST
• EXTERNPROTO nodeTypeName nodeInterface
  urls

50
Type of Virtual Reality
51
Non Immersive VR

• Systems that includes mouse-controlled navigation
  through a three-dimensional environment on a
  graphics monitor, stereo viewing from the monitor
  via stereo glasses, stereo projection systems,
  and others.
• Apple's Quick Time VR , Spherical RealVR ,
  Smoothmove , VRML , and Java3d , for example,
  uses photographs for the modeling of
  three-dimensional worlds and provides pseudo
  look-around and walk-trough capabilities on a
  graphics monitor.

52
Non Immersive Example
53
Non Immersive Example

• Scientific Visualization and Visual Simulation

54
Immersive VR

• Head-referenced viewing provides a natural
  interface for the navigation in three-dimensional
  space and allows for look-around, walk-around,
  and fly-through capabilities in virtual
  environments.
• Stereoscopic viewing enhances the perception of
  depth and the sense of space.
• The virtual world is presented in full scale and
  relates properly to the human size.
• Realistic interactions with virtual objects via
  data glove and similar devices allow for
  manipulation, operation, and control of virtual
  worlds.
• The convincing illusion of being fully immersed
  in an artificial world can be enhanced by
  auditory, haptic, and other non-visual
  technologies.
• Networked applications allow for shared virtual
  environments

55
Shared Virtual Environments

• All users see the same virtual environment from
  their respective points of view. Each user is
  presented as a virtual human (avatar) to the
  other participants. The users can see each other,
  communicated with each other, and interact with
  the virtual world as a team.
• Networked users at different locations (anywhere
  in the world) meet in the same virtual world by
  using a BOOM device, a CAVE system, and a
  Head-Mounted Display, respectively.

56
Shared Virtual Environments Example
57
Immersive Example
58
VRML and VR

• Current location
• The vrmLab Town Square US
• Operational since VRML first began, the
  vrmLab is probably the oldest continuously-display
  ed and -developed VRML scene in the world
• Cyber-JRC Italy
• A project of the European Commission's Joint
  Research Centre, Cyber-JRC extends experiments in
  "Tele-presence for Entertainment, Surveillance,
  and Training" through the use of VNet
• The Digital Garden Germany
• A "Final year Diploma-Thesis at FH-Nürtingen
  Germany" by Mirko Ross, " plays with the
  characteristic garden picture formed by history"
  

59

• Forest World Sweden
• The rolling hills of Niclas Olofsson's
  forest world
• Electra City Australia
• A peaceful island from the imagination of
  Miriam English
• The Ancient Village Project Germany
• A project of the German VRML Users Group
  (GerVRML), Oliver Schlueter's Ancient Village is
  designed to act as a set for theater performances
  and role-playing games
• Browser Test World Canada
• Available to test browser and plugin
  combinations, EAISimple.wrl contains the minimal
  elements needed to enter a VNet scene

60
Blaxxun Cybertown
Please Click Window
61
Some General Applications

• Engineering/Design and R D
• Vehicle interior/exterior design and analysis
• Visibility and operation design, simulation and
  analysis
• Rapid product prototyping
• Fluid flow dynamics
• Aerodynamic evaluation
• Pollution emission studies
• Remote collaborative design and testing
• Motion studies

62
Some General Applications

• Manufacturing
• Manufacturing and assembly design and simulation
• Robotics
• Subassembly analysis
• Teleoperations and telepresence
• Medicine
• Volumetric human anatomy visualization
• Surgical simulation, research and training
• Molecular and structural biology

63
Some General Applications

• Architecture
• Site plan analysis
• Structural aspect review
• Space planning ,Site line analysis
• Interior design
• Urban planning
• Shared context environments
• Marketing
• Product planning,Package design

64
Some General Applications

• Geophysical Exploration
• Oceanography
• Seismology
• Other Applications
• Astrophysics
• Atmospheric science
• Ecological impact
• Geometric modeling
• Microphysics
• Hazardous material handling simulation and
  training

65
Demo

• NIST
• Pipes Proto
• Loader Demo
• Air Flow Demo

66
VRML CAVE development

• EVL (Electronic Visualization Laboratory)
• Dave Papa (Pape_at_evl.uic.edu)
• http//www.evl.uic.edu/pape/CAVE/
• VA TECH
• Ron Kriz (kriz_at_wave.esm.vt.edu) and Debby Hix
• http//www.cave.vt.edu/
• Vnet MultiUser (Shared VRML Worlds)
• http//ariadne.iz.net/jeffs/vnet/

67
CAVE (Cave Automatic Virtual Environment)

• "CAVE," the name selected for the virtual reality
  theater, is both a recursive acronym (Cave
  Automatic Virtual Environment) and a reference to
  "The Simile of the Cave" found in Plato's
  Republic, in which the philosopher explores the
  ideas of perception, reality, and illusion.
• Plato used the analogy of a person facing the
  back of a cave alive with shadows that are
  his/her only basis for ideas of what real objects
  are.

68
CAVE Goal

• Goals that inspired the CAVE engineering effort
  include
• The desire for higher-resolution color
  images and good surround vision without
  geometric distortion.
• Less sensitivity to head-rotation induced
  errors
• The ability to mix virtual reality imagery
  with real devices (like one's hand, for instance)
  
• The need to guide and teach others in a
  reasonable way in artificial worlds
• The desire to couple to networked
  supercomputers and data sources for successive
  refinement

69
EVL (Electronic Visualization Laboratory)CAVE

• Demo
• Cave Demo
• Concept Prototype

70
Cave Demos

• University of Illinois, Chicago
• 20 CAVE Demos at EVL in 2D (HTML)
• CAVE Demos at EVL in 3D (VRML)
• University of Illinois, Urbana-Champaign
• The Crumbs Project, "On the Trail of 3D Images"
• Iowa State University
• Virtual Prototyping
• Manufacturing
• Haptics
• Architecture

71
References

• Web
• www.web3d.org , www.vrml.org ,
• http//www.fas.org/man/index.html
• http//www.rccad.com/Gallery.htm
• http//web3d.about.com/compute/web3d/msubclip.htm
• Books
• VRML 2.0 Sourcebook
• by A. L. Ames ,D.R. Nadeau, J. L. Moreland
• Late Night VRML2.0 w/Java
• B. Roehl, J. Couch, C. Reed-Ballriech, T.
  Rohaly, G. Brown

72
Questions
73
Summary

• VMRL has many different applications, from the
  entertaining to the applied. It is a tool that if
  used can enable the author of content to create
  anything they desire.

74
Final Thought

• "Cyberspace. A consensual hallucination
  experienced daily by billions of legitimate
  operators, in every nation, by children being
  taught mathematical concepts. A graphic
  representation of data abstracted from the banks
  of every computer in the human system.
  Unthinkable complexity. Lines of light ranged in
  the non-space of the mind, clusters and
  constellations of data. Like city lights,
  receding."
• (William Gibson, Neuromancer, p. 103)