What is VRML?

• VRML = Virtual Reality Modeling Language
• VRML is a scene description language for creating 3D objects and evironments
• VRML was primarily designed for delivering virtual environments over the Internet
• VRML is an ISO standard

Applications

VRML can be used for a large variety of applications:

• Multi-user environments
• Design review
• Product demonstrations
• Games
• Education
• Training
• Simulation
• etc...

Brief history

• First International Conference on the World Wide Web (May, 1994), Mark Pesce and Tony Parisi present "Labyrinth", a tool for visualising the Web
• A consistent cyberspace defined using VRML is proposed to improve navigation of the Web, but discussion and activity that followed resulted in a specification for a common language for defining 3D scenes rather than an interface to the Web
• VRML 1.0 (May 1995), a language for defining static virtual worlds with Web anchors, based on Silicon Graphics' OpenInventor file format
• VRML 2.0 (August 1996) is a much more powerful language for defining dynamic virtual worlds, with animation, user interaction and program scripts
• VRML 97 (April 1997), ISO/IEC DIS 14772, is a revision of VRML 2.0

Key concepts

Visualiser

• Virtual environments are realised by a player (browser) that interprets, executes, and presents VRML files

File Structure

• A VRML file contains at least a header and nodes

Nodes

• Nodes have field and field values that describe their attributes

Scene Graph

• Nodes are arranged in a 'scene graph'
• Grouping nodes can contain any number of other nodes (children)
• An Inline node is a kind of grouping node where the child nodes are defined in another VRML file

Shape nodes

• Shape nodes are used to define shapes with appearance and geometry
• Predefined geometry nodes are Box, Cone, Cylinder and Sphere nodes
• Complex shapes can be built by grouping predefined shapes together and/or using a PointSet, IndexedLineSet, or a IndexedFaceSet, and/or using an Extrusion node

Instancing

• The same node can be reused in a scene graph by instancing it. An instance is a kind of alias. The keywords DEF and USE are used to handle instancing. DEF is also used to simply name nodes

User Interaction

• User interaction is handled using Sensor nodes

Prototypes

• New node types can be created using prototype definitions

Events

• Most node types have eventIn and eventOut fields
• A 'route' can be used to connect a node's eventOut field to another node's eventIn field, enabling nodes to send events to each other
• Events typically contain values that affect the state of the receiving node
• Dynamic environments can be created by wiring nodes together into circuits