Sustainability of Digital Formats: Planning for Library of Congress Collections

Virtual Reality Modeling Language (VRML) describes interactive, networked 3D objects and virtual worlds. The specification, defined by the Web3D Consortium and ISO/IEC, describes VRML as "a 3D time-based space that contains graphic and aural objects that can be dynamically modified through a variety of mechanisms." See Disclosure for more details. VRML represents static and animated 3D objects and can include hyperlinks to other media. The goal of VRML is stated as (link via Internet Archive) "to create the infrastructure and conventions of cyberspace, a multi user space of many virtual worlds on the Net."

According to the VRML FAQ (link via Internet Archive), it is usually pronounced with the letters spelled out, "V R M L", but "its friends pronounce it 'vermel'," a phrase also used in a VRML timeline (link via Internet Archive).

VRML went through several iterations, with two major versions (1.0 and 2.0) and a 1.1 draft version. VRML 1.0 worlds were static, while VRML 2.0 worlds allowed for movement and interaction. VRML 2.0 is also referred to as VRML97 (link via Internet Archive) or ISO/IEC 14772-1:1997.

VRML files describe a time-based, interactive, 3D virtual environment. These environments can include hyperlinks and other multimedia information. The files describe all objects included in the 3D virtual environments, referred to as "worlds", along with object behaviors and events.

A crucial element of this format is that it is intended to be used in a distributed web environment. VRML can hyperlink to other files using established Internet standards. VRML worlds can change dynamically in response to user inputs, external events, and the current state of the (virtual) world. Script nodes can receive, process, and send events.

In terms of technical structure, a VRML file contains zero or more root nodes. Each node has the following characteristics: a type name, zero or more fields that define each node, a set of events that it can receive and send, implementation, and a name. VRML can describe shapes and geography, bounding boxes, light sources, sensor nodes, time sensors, grouping and children nodes, and many other types of children nodes.

The specification also supports the concept of profiles. A profile is "a named collection of functionality and requirements which shall be supported in order for an implementation to conform to that profile."

VRML has been published as following versions, with many available at The VRML Repository (link via Internet Archive):

• VRML 1.0 Draft Specification
• VRML 1.0 Final Specification
• VRML 1.0C Specification (with clarifications) (link via Internet Archive)
• VRML 1.1 Draft Specification
  This draft was meant to (link via Internet Archive) add "a few features to do sound and simple animations, but not enough to start multi-user development." Instead of pursuing VRML 1.1, the VRML Architecture Group chose to push forward to VRML 2.0 instead.
• VRML 2.0 Draft #1 Specification
• VRML 2.0 Draft #2b Specification
• VRML 2.0 Draft #3 Specification
• VRML 2.0 Final Specification

VRML 2.0 is also known as VRML97. These are used interchangeably.

This is considered a legacy format. Most adopters have moved to X3D, WebGL or other formats.

The specification acknowledges that VRML "may be used in a variety of application areas such as engineering and scientific visualization, multimedia presentations, entertainment and educational titles, web pages, and shared virtual worlds."

Many companies (link via Internet Archive) were involved with VRML, several browsers (link via Internet Archive) developed for VRML, several published books (link via Internet Archive), a robust official mailing list, www-vrml, and USENET newsgroup (alt.lang.vrml) (link via Internet Archive), and an additional unmoderated USENET newsgroup (comp.lang.vrml). There were additional listservs (link via Internet Archive) and newsgroups (link via Internet Archive).

VRML files are used by VRML browsers. This may be a dedicated browser or built into a web browser such as Netscape Navigator.

The VRML FAQ (link via Internet Archive), under "2.1: What browsers are available?" is "I can't keep up with these!" The VRML Repository (link via Internet Archive) provides a long list, including which VRML versions they support. W3's VRML page mentions two browsers by name: WorldView from Intervista and WebSpace from SGI.

VRML 1.0 and 2.0 support textures on objects. Geometry has "material" properties that describe how light can reflect off the surface of an object. Transformations (scale, rotate, translate) can be used to position and scale an object in relation to others. VRML 2.0 supports textures and colors for backgrounds. Four node types specify texture maps: Background, ImageTexture, MovieTexture, and PixelTexture.

VRML defines the following light source nodes: DirectionalLight, PointLight, and SpotLight. The specification (4.6.6. Light sources) states: "Shape nodes are illuminated by the sum of all of the lights in the world that affect them. This includes the contribution of both the direct and ambient illumination from light sources. ... All light source nodes contain an intensity, a color, and an ambientIntensity field."

The specification states that "Each VRML file implicitly establishes a world coordinate space for all objects defined in the file, as well as all objects included by the file."

VRML 1.0 and 2.0 support the ability to move through scenes, lights, and viewpoints. VRML 2.0 supports background colors and textures.

VRML has the following Sensor nodes: Anchor, Collision, CylinderSensor, PlaneSensor, ProximitySensor, SphereSensor, TimeSensor, TouchSensor, and VisibilitySensor. These nodes are either environmental or pointing-device sensors.

The Background, Fog, NavigationInfo, and Viewpoint nodes are limited in that only one of each can be impacting the user's view at any point in time.

While VRML 1.0 worlds are static, VRML 2.0 supports movement and more interactivity. VRML 2.0 supports animated objects, switches and sensors, Java or JavaScript to change behaviors, sound (WAV or MIDI), animating textures, and event routing.

VRML worlds contain viewpoints, navigation (including actions by users), and movement. The NavigationInfo node (Section 6.29 of the specification) details these characteristics.

Interpolator nodes are designed for linear keyframed animation. See 4.6.8 Interpolator nodes in the specification for more detail.

VRML has TimeSensors to generate time-based events. These can run more quickly or slowly than "real world" time, but by default it will run in "real" time. Time-dependent nodes (Section 4.6.9 of the specification) are defined as "AudioClip, MovieTexture, and TimeSensor are time-dependent nodes that activate and deactivate themselves at specified times. Each of these nodes contains the exposedFields: startTime, stopTime, and loop, and the eventOut: isActive."

From section "4.5.1 File extension and MIME types": "The official MIME type for VRML files is defined as model/vrml where the MIME major type for 3D data descriptions is model, and the minor type for VRML documents is vrml.

The specification also notes, for backwards compatibility, that the following must also be supported: x-world/x-vrml

VRML files begin with: #VRML [version] [encoding type] [optional comment] [line terminator]

For example:

#VRML V2.0 utf8

There must be exactly one space between "#VRML" and the version, and between the version and encoding type. The encoding type must "be followed by a linefeed (0x0a) or carriage-return (0x0d) character, or by one or more space (0x20) or tab (0x09) characters followed by any other characters, which are treated as a comment, and terminated by a linefeed or carriage-return character."

The specification outlines the following design criteria intended when building the language: Authorability, Composability, Extensibility, Be capable of implementation, Performance, and Scalability.

According to a talk by Mark Pesce (link via Internet Archive), an earlier name for what would become VRML was "Labyrinth." Work began in February, 1994, and Pesce and Dave Raggett were invited by Tim Berners-Lee to present at the First International Conference on the World Wide Web in April 1994 (link via Internet Archive), where the phrase "Virtual Reality Markup Language" was coined by Raggett. The www-vrml mailing list was started in June 1994, which grew to over a thousand members. From this list, the VRML 1.0 Draft was drafted and subsequently published in November 1994, with the first VRML browsers releasing in May 1995.

The VRML Architecture Group (VAG) was founded (link via Internet Archive) in August 1995. This group, along with the larger VRML community, worked towards the development of VRML 2.0. On August 4, 1996, the official VRML 2.0 Specification was released at Siggraph 96 in New Orleans. The VRML Architecture Group site (link via Internet Archive) includes more details and meeting notes.

In December 1996, co-creator of VRML, Mark Pesce, resigned (link via Internet Archive) from the VRML Consortium and sent an "open letter to the VRML community," warning that powerful corporations are threatening the interests of content producers and users in the push to promote and improve VRML. The letter, emailed Tuesday, came a day before the Consortium's existence was to be officially announced." The VRML consortium was rebranded (link via Internet Archive) as the Web3D Consortium. z`

According to the Geeksforgeeks Introduction to VRML, VRML format is no longer widely used, replaced by technologies such as X3D and WebGL.