VRML Tutorial.

  1. What you need to start.
  2. What is a scene graph?
  3. VRML Nodes
  4. A Simple Example
  5. Tutorial Links
. What is a scene graph?

A scene graph is the structure of the world being created. The VRML file format allows you to create a scene graph using words and punctuation. This is why you can create VRML scene graphs using a simple text editor like HTML.
The scene graph is made up of a group of objects that when rendered exist in 3D space. VRML has many object types. The simplest are known as "primitive objects" because they can be described in simple terms. These primitive objects include box, cone, cylinder and sphere. These can be used together to make more complex objects.
VRML is made up of more than 60 node types. A "node" is a piece that implements some functionality. These nodes fit together in such a way that some have other nodes below them. The node above is called the "parent" node and the node below is called the "children" node. The relationship between parent nodes and children nodes is called the "scene graph hiearchy".
Within each node is a list of "fields" and "events" which hold values that define the parameters for that nodes function.
For example: The fields for the cone node define the height of the cone and the radius at its base.
VRML has three types of nodes:

  1. Grouping nodes which contain a list of other nodes.
  2. Children nodes which can be contained in the children lists.
  3. Attribute nodes which are contained in a specific field of a specific node. They add attributes to shapes, sounds, etc.

As these nodes are grouped in their hiearchy, the scene takes shape. Different nodes change different attributes including shape, size, sound, lighting, viewpoint, and many others.
VRMLscripting can also be added to the scene graph. The script node allows you to create your own fields and events, and define the way they work by writing a "script" or sequence of user-defined instructions.
VRML supports many programming languages for writing scripts including Java language. VRMLscript is similar to Java but simpler. It is a subset of Javascript. VRMLscript is very flexible and forgiving in what can be in the list of parameters of a function. This scripting allows you to do things in your world like have a door open only if the right combination is entered by the user on the keypad at the door.

VRML Nodes

Anchor
Appearance
Cylinder
CylinderSensor
ElevationGrid
Group
IndexedLineSet
Material
NavigationInfo
OrientationInterpolator
PlaneSensor
PositionInterpolator
ProximitySensor
Shape
Sound
SpotLight
Switch
TimeSensor
Viewpoint
VisibilitySensor
Audioclip
Background
CoordinateInterpolator
DirectionalLight
Extrusion
ImageTexture
Inline
Normal
PixelTexture
PointLight
ScalarInterpolator
Sphere
Text
TextureCoordinate
TouchSensor
WorldInfo
Cone
Coordinate
ColorInterpolator
Fog
FontStyle
IndexedFaceSet
LOD
MovieTexture
NormalInterpolator
PointSet
Script
SphereSensor
TextureTransform
Transform
All of these nodes have corresponding fields and events.

Simple Examples

Geometry8.wrl
Geometry7.wrl
Geometry2.wrl
These examples are from the tutorial site of Roland Smeenk at:www.a1.n1/homepages/rsmeenk.

Tutorial Links

http://www.a1.n1/homepages/rsmeenk/index.htm http://www.wasabisoft.com/Book/ch3.htm
http://tom.di.uminho.pt/vrml/
http://www.ywd.com/cindy/vrml_tex.html
http://www.ywd.com/
http://www.wdvl.com/
http://www.meshmart.org
http://www.webreference.com/3d


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