The Virtual Reality Modeling Language

3. Definitions

Version 2.0, ISO/IEC WD 14772

August 4, 1996

appearance node

A node of type Appearance, FontStyle, ImageTexture, Material, MovieTexture, PixelTexture, or TextureTransform. Appearance nodes control the rendered appearance of the geometry nodes with which they are associated.

bindable leaf node

A node of type Background, Fog, NavigationInfo, or Viewpoint. These nodes may have many instances in a scene graph, but only one instance may be active at any instant of time.

children nodes

Nodes which are parented by grouping nodes and thus are affected by the transformations of all ancestors. See "Concepts - Grouping and Children Nodes" for list of allowable children nodes.

colour model

Characterization of a colour space in terms of explicit parameters.VRML allows colors to be defined only with the RGB color model.

display device

A graphics device on which VRML scenes can be represented.

drag sensor

Drag sensors (CylinderSensor, PlaneSensor, SphereSensor) cause events to be generated in response to pointer motions which are sensor-dependent. For example, the SphereSensor generates spherical rotation events. See "Concepts - Drag Sensors" for details.


Messages sent from one node to another as defined by a Route. Events signal changes to field values, external stimuli, interactions between nodes, etc.

exposed field

A field which can receive events to change its value(s) and generates events when its value(s) change.

execution model

The characterization of the way in which scripts execute within the context of VRML.

external prototype

Prototypes defined in external files and referenced by a URL.


The parameters that distinguish one node from another of the same type. Fields can contain various kind of data and one or many values.

geometry node

Nodes of type Box, Cone, Cylinder, ElevationGrid, Extrusion, IndexedFaceSet, IndexedLineSet, PointSet, Sphere, and Text which contain mathematical descriptions of three-dimensional points, lines, surfaces, text strings and solid objects.

geometric property node

A node of type Color, Coordinate, Normal, or TextureCoordinate. These nodes define the properties of specific geometry nodes.

geometric sensor node

A node of type ProximitySensor, VisibilitySensor, TouchSensor, CylinderSensor, PlaneSensor, or SphereSensor. These nodes generate events based on user actions, such as a mouse click or navigating close to a particular object.

grouping node

A node of type Anchor, Billboard, Collision, Group, or Transform. These nodes group child nodes and other grouping nodes together and cause the group to exhibit special behavior which is dependent on the node type.


Internet Engineering Task Force. The organization which develops Internet standards.


An instantiation of a previously defined node created by the USE syntax.

interpolator node

A node of type ColorInterpolator, CoordinateInterpolator, NormalInterpolator, OrientationInterpolator, PositionInterpolator, or ScalarInterpolator.These nodes define a piece-wise linear interpolation of a particular type of value at specified times.


Joint Photographic Experts Group.


Musical Instrument Digital Interface - a standard for digital music representation.


Multipurpose Internet Mail Extension used to specify filetyping rules for browsers. See "Concepts - File Extension and MIME Types" for details.


The fundamental component of a scene graph in VRML. Nodes are abstractions of various real-world objects and concepts. Examples include spheres, lights, and material descriptions. Nodes contain fields, and events. Messages are sent between nodes via routes.

node type

A required parameter for each node that describes, in general, its particular semantics. For example, Box, Group, Sound, and SpotLight. See "Concepts - Nodes, Fields, and Events" and "Nodes Reference" for details.


The definition of a new node type in terms of the nodes defined in this standard.


The VRML colour model. Each colour is represented as a combination of the three primary colours red, green, and blue.


The connection between a node generating an event and a node receiving an event.

scene graph

An ordered collection of grouping nodes and leaf nodes. Grouping nodes, such as Transform, LOD, and Switch nodes, can have child nodes. These children can be other grouping nodes or leaf nodes, such as shapes, browser information nodes, lights, viewpoints, and sounds.

sensor node

A node of type Anchor, CylinderSensor, PlaneSensor, ProximitySensor, SphereSensor, TimeSensor, TouchSensor, or VisibilitySensor. These nodes detect changes and generate events. Geometric sensor nodes generate events based on user actions, such as a mouse click or navigating close to a particular object. TimeSensor nodes generate events at regular intervals in time.

special group node

A node of type LOD (level of detail), InLine, or Switch. These nodes are grouping nodes which exhibit special behavior, such as selecting one of many children to be rendered based on a dynamically changing parameter value or dynamically loading its children from an external file.

texture coordinates

The set of 2D coordinates used by vertex-based geometry nodes (e.g. IndexedFaceSet and ElevationGrid) and specified in the TextureCoordinate node to map textures to the vertices of some geometry nodes. Texture coordinates range from 0 to 1 across the texture image.

texture transform

A node which defines a 2D transformation that is applied to texture coordinates.


Uniform Resource Locator as defined in IETF RFC 1738.


Uniform Resource Name

VRML document server

An application that locates and transmits VRML files and supporting files to VRML client applications (browsers).

VRML file

A file containing information encoded according to this standard.

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