PowerPointPrsentation

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Proseminar Web3D Sommersemester
2002 Introduction to Java3D 13.06.2002 Anni
e Michele Nguedia
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Overview(1)

• I - General 3D Modelling concepts
• II - Definition of a SceneGraph
• - SceneGraph superstructure
• - SceneGraph nodes
• - Node Component
• - Scenegraph references
• III - Important classes to develop a Java3D
• - Java3D API
• - SceneGraph Classes

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Overview(2)

• IV - Recipe for writing a Java 3D program
• V - Tranformations in Java3D
• - Rotation, translation, scaling
• VI - Key Java 3D features
• VII - Summary
• VIII - References

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Java 3D an approach

• Java 3D is a set of classes for writing
  three-dimensional graphics applications and 3D
  applets.
• It is primarily for application
  developer(programmer).
• It enables authors to build shapes and control
  animation and interaction.
• It also enables detailed control over rendering,
  input devices, the viewing model, and lots more.
• API implementation was recently released by Sun
  Microsystems.

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General 3D Modelling Concepts

• A Java 3D virtual universe is created from a
  SceneGraph.
• The most common relationship in a SceneGraph is a
  parent child relation
• (as in VRML)

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• General 3D Modelling concepts
• II - Definition of a SceneGraph
• - SceneGraph superstructure
• - SceneGraph nodes
• - Node Component
• - Scenegraph references
• III - Important classes to develop a Java3D
• - Java3D API
• - SceneGraph Classes

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Definition of a SceneGraph (1)

• SceneGraphs are treelike data structures that
  are used to store, organize , and render scene
  information (objects,materials,
  appearances,lights....Etc).
• The data structures of a scene graph consist of
  Nodes.

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Definition of a SceneGraph (2)

• The most important Nodes that are composed a
  scene graph are a Virtual Universe,a Locale(or
  more) ,Groups, Leaf,NodeComponents and others
  objects .

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Scene Graph Symbols
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Together a Locale and a Virtual Universe
compose a SceneGraph superstructure.

• A reference associates a Node
• Component object with a Scene
• Graph Node .

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Scenegraph nodes

• There are two types of nodes
• - Group the primary role of a Group is to
  act as the parent of the other nodes, specially
  other Group nodes and Leaf nodes.
• - Leaf leaf nodes specify the shape, sound,
  and behavior of a scene graph object.

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Group nodes subclasses
BranchGroup
OrderedGroup
SharedGroup
Group
Switch
TransformGroup
Primitive
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Leaf nodes Subclasses
Background
Behavior
Bounding Leaf
Clip
Fog
Leaf
Light
Link
Morph
Shape3D
Sound
Soundscape
Viewplatfom
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The Node Component

• The Java3D Node Component class is used to
  specify a variety of node properties such as
  geometry,appeareance ,texture, transparency,and
  coloring.
• The classes of Node Component are
  Appeareance,AuralAttributes,Coloring Attributes
  ,DepthComponent Geometry,ImageComponent,....

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• General 3D Modelling concepts
• Definition of a SceneGraph
• - SceneGraph superstructure
• - SceneGraph nodes
• - Node Component
• - Scenegraph references
• III - Important classes to develop a Java3D
• - Java3D API
• - SceneGraph Classes

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Java3D API
The API has core classes and utility classes

• Core Classes
• javax.media.j3d package
• lowest level classes required for Java3D
  programming

• Utility Classes
• com.sun.j3d.utils package
• convenient and powerful additions to the core

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Important Classes

• Virtual Universe und Locale Class
• are derived respectively from Universe and
  Locale Object in a scene Graph.
• SceneGraph Object Class
• is the base class for nearly every object
  that appears in a Java3D scene Graph.This
  abstract class contains node and node component
  objects.
• Scene Graph Viewing Object Classes
• included five classes that are used in the
  viewing parameters of scene graphs
  (Canvas3D,Screen3D,View,PhysicalBody,PhysicalEnvir
  onment).
• Simple Universe utility class
• is used by the Java3D developers to
  create a Java3D program without dealing with
  Viewing object Classes.

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Simple recipe for writing a Java3D program

• Using the SimpleUniverse class in Java 3D program
  reduces the time and effort needed to create the
  view branch Graph.
• The basic outline of Java 3D program development
  consists of seven steps
• 1- Create a Canvas3D object
• 2- Create a VirtualUniverse object
• 3- Create a Locale object, attaching it to
  the VirtualUniverse object .
• 4- Construct a View object
• 5- Construct content branch graph
• 6- Compile branch graph
• 7- Insert subgraphs into the Locale.
• The steps 1,2,3,4,and 7 create a Simple Universe(
  code for creating a SimpleUniverse
  SimpleUniverse ( ) )

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HelloJava3D Class

• public class HelloJava3Da extends Applet
• public HelloJava3Da()
• setLayout(new BorderLayout())
• GraphicsConfiguration config
• SimpleUniverse .getPreferredConfiguraton(
  )
• Canvas3D canvas3D new Canvas3D (config)
  
• add("Center, canvas3D)
• BranchGroup scene createSceneGraph()
• scene.compile()
• // SimpleUniverse is a convenience Uility
  class
• SimpleUniverse SimpleU new
  SimpleUniverse (canvas 3D)
• // This move the ViewPlatform back a bit so
  the
• // objects in the scene can be viewed .
• SimpleU.getViewingPatform().setNominalViewin
  gTransform()
• simpleU.addBranchGraph (scene)
• // end of HelloJava 3Da (constuctor)

1- Create a canvas3D
4- Compile ContentBranchGraph
2- Create a Simpleuniverse
3- Customize Simpleuniverse
5- Insert ContentBranchGraph into the Locale
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Some terminologies in Java3D

• Become live
• a Branch Graph becomes live as soon as it is
  attached to a scene graph. Each object of the
  Branch Graph are subject to being rendered.
• Compiling
• a BranchGroup converts an object and all its
  ancestors to a more efficient one from the
  rendered.

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• General 3D Modelling concepts
• Definition of a SceneGraph
• Important classes to develop a Java3D
• Recipe for writing a Java 3D program
• V - Transformations in java 3D
• - Translation
• - Rotation
• - Scaling
• VI - Key Java 3D features
• VII - Summary
• VIII - References

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Transfomations in Java3D

• The TransformGroup Class is the needed class to
  represent a transformation of a Transfom3D
  object.
• The three basic operations for a transformation
  are
• - Translation moving object from one
  location in space to another .
• - Rotation An object can be rooted around
  any combination of the X,Y,Z axes
  simultaneously.
• - Scalingscaling an object means changing
  ist size .There are two different types of
  scaling uniform and nonuniform.

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Key Java3D features

• Java 3D scene graphs are considerably more
  difficult than a VRML scene graph,owing to the
  inherent complexity of full-featured programming
  languages such as Java.
• Further than its complexity ,Java3D sceneGraph
  offers excellent features such as
• - Rendering control
• - Scalable Performance
• - Behaviors
• - Generic Input Devices
• - Geometry Compresion
• - Versatile View Model
• - Camera-based View Model

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Actual future works(1)

• Virtual Reality (VR)application could be
  developped with Java3D
• VR application insert other parameters such as
• - users physical characteristic (height,
  eyeseparation,...)
• - physical environment (number of displays,
  their location , head-tracked-shutter-glass-based
  desktop).

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Actual future works(2)
Some devices for VR
Advance 3D Model
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Conclusion

• Java programmers can quickly and easily define
  graphics programs using Java3Ds scene graph
  classes.

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References

• Getting starting with Java3D API (Dennis J
  Bouvier) The Java3D Tutorial of Sun
• Java website http//java.sun.com/products/javamedi
  a/3D
• http//www.sun.com/desktop/java3d

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• Thank you for your attention !