VRML
More actions
The Virtual Reality Modeling Language (VRML) is a file format for describing interactive 3D objects and worlds, designed for use on the Internet, intranets and local client systems.[1] It grew out of a 1994 effort to give the web an equivalent of HTML for three-dimensional space, in which users could move through a 3D scene and follow hyperlinks attached to objects in it.[2][3] VRML 1.0, based on the Open Inventor file format of Silicon Graphics, described static scenes; VRML 2.0 (1996) added animation, sensors, sound and scripting, and was published by ISO and IEC as the international standard ISO/IEC 14772-1:1997, usually called VRML97.[4]
VRML was an early attempt to deliver virtual reality content through an ordinary web browser. Its worlds were usually viewed through a plug-in installed in a 2D web browser such as Netscape or Internet Explorer,[5] and the World Wide Web Consortium's 1995 page on the format noted that it let virtual worlds be specified "without being dependent on special gear like head-mounted devices (HMD)".[6] The Library of Congress now classes it as a legacy format; it was superseded by X3D, which the Web3D Consortium developed from VRML and which keeps a "Classic VRML" encoding.[4][7] Its co-creator Tony Parisi later argued that the ideas behind VRML returned in WebGL, WebVR and glTF.[8]
History
Labyrinth and the first web conference
Software developer Tony Parisi met Mark Pesce in San Francisco in 1993, after Pesce had left the virtual reality hardware startup Ono-Sendai. Parisi later recalled that the two built a demo called Labyrinth "which let you browse the web with some 3D graphics connected to it".[9] Pesce, Peter Kennard and Anthony S. Parisi of the Labyrinth Group wrote a paper titled "Cyberspace" for the First International Conference on the World-Wide Web, held in Geneva in May 1994.[10] Parisi recalled that the group answered a call for virtual reality proposals put out by David Raggett, and that only Pesce traveled to Geneva because they could not afford two plane tickets.[9] The paper proposed bringing the web's model "from two dimensions, out, at a right angle, into three", which the authors said required "extensions to HTML to describe both geometry and space; and a unified representation of 'space' across Internet". The paper described Labyrinth as a WWW client "which visualizes WWW as a space", with its own Labyrinth Scripting Language for object definitions, scene placement and the binding of a URL to an object. Labyrinth world files were a separate data type that launched a companion viewer through MIME. The authors described a single cyberspace spanning the Internet, in the "Gibsonian" sense associated with William Gibson, that existed only as a "consensual hallucination" of the hosts and users taking part in it; there could be only one cyberspace, they argued, just as there was only one WWW.[10]
David Raggett of Hewlett-Packard Laboratories wrote that at the same conference he ran a birds-of-a-feather session with Tim Berners-Lee at which he presented his vision for "a platform independent 3D standard for the Web", using the term VRML, and that he presented the concept the following month at the Internet Society conference in Prague. His paper, "Extending WWW to Support Platform Independent Virtual Reality", proposed letting users walk around virtual environments and "push through doors to follow hyperlinks to other parts of the Web". Raggett suggested composing scenes from "a limited set of logical elements, e.g. chair, door, and floor", drawing on experience with SGML, using URLs to reference shared resources such as models and image tiles, and a new MIME content type, video/vrml.[2] Parisi confirmed in 2015 that Raggett "came up with the term" VRML.[9]
The VRML 1.0 specification records that Berners-Lee and Raggett organized a birds-of-a-feather session on virtual reality interfaces to the web at the Geneva conference. Participants agreed on the need for "a common language for specifying 3D world description and WWW hyper-links", and the term "Virtual Reality Markup Language" was coined there; "Markup" was later changed to "Modeling" "to reflect the graphical nature of VRML".[3][11]
VRML 1.0
After Geneva the www-vrml mailing list was set up to write the specification, and according to the specification "within a week, there were over a thousand members". Pesce, as list moderator, set the goal of a draft in time for the fall 1994 web conference.[3] Don Brutzman's 1998 account in Communications of the ACM says that open nomination and discussion of seven candidate technologies led to the selection of an extended subset of the Silicon Graphics (SGI) Open Inventor file format.[5] SGI released the Open Inventor ASCII format for open use and contributed a parser to the public domain so that viewers could be built quickly.[3] Parisi recalled that he and Pesce "teamed up with Rikk Carey and Gavin Bell from Silicon Graphics" and chose Open Inventor as the basis.[9]
The specification lists Gavin Bell (Silicon Graphics), Anthony Parisi (Intervista Software) and Mark Pesce (VRML List Moderator) as authors. Its revision history gives a first draft on 2 November 1994, a second draft on 8 May 1995, the first 1.0 specification on 26 May 1995 and a clarified version, VRML 1.0C, on 29 January 1996.[3] Behaviors were deliberately left out: the specification explains that "by keeping behaviors out of Version 1, we have made it a much smaller task to implement a viewer".[12] VRML 1.0 worlds were therefore static, but they could contain hyperlinks (the WWWAnchor node, equivalent to an HTML link), inline geometry loaded from other files, multiple lights and level-of-detail switching.[4][11]
In July 1995 Wired described VRML as "a technical standard for creating navigable, hyperlinked 3-D spaces on the World Wide Web", endorsed by Silicon Graphics, Netscape, Digital and NEC, and reported that Parisi's company Intervista Software would soon release a VRML browser called WorldView built on Rendermorphics' Reality Lab renderer.[13] The W3C's VRML page of April 1995 listed two viewers, WorldView from Intervista and WebSpace from SGI.[6] Parisi later said that Intervista partnered with Microsoft, that WorldView "was actually distributed with Internet Explorer for several years", and that about 10 million copies were installed on PCs worldwide.[9]
VRML 2.0 and VRML97
The VRML Architecture Group (VAG), a group of eight technical experts, held its first meeting from 20 to 23 August 1995 in Half Moon Bay, California. At its second meeting in October 1995 it moved from technical design to process guidance and issued a request for proposals for VRML 2.0.[14] A draft VRML 1.1 that would have added sound and simple animation was dropped in favor of going directly to 2.0.[4] By the end of 1995 several companies, including Silicon Graphics and Microsoft, were already building replacements for VRML 1.0, and the open selection process was meant to prevent the standard from fragmenting.[11]
Six proposals were submitted: Active VRML (Microsoft), Dynamic Worlds (GMD and others), HoloWeb (Sun), Moving Worlds (Silicon Graphics and others), Out of this World (Apple) and Reactive Virtual Environment (IBM Japan).[11] Moving Worlds was backed by Netscape, Silicon Graphics, Sony and about 50 other companies.[15] In the final public poll, dated 18 March 1996, 138 of 186 respondents (74 percent) named Moving Worlds as the proposal they most strongly favored, against 18 (10 percent) for Active VRML.[16] On 25 March 1996 the VAG unanimously agreed that Moving Worlds would become the working document for VRML 2.0, and the final VRML 2.0 specification was released on 4 August 1996 at SIGGRAPH 96 in New Orleans.[14]
VRML 2.0 added sound, movie textures, fog, backgrounds, terrain and extrusion geometry, and a simplified scene graph. Objects could move and respond to user actions and to time through sensors, interpolators and routes, and more complex behavior could be written in JavaScript or Java. A prototyping mechanism let authors define new, reusable node types.[11] Brutzman wrote that two major limitations of VRML 1.0 had been the "lack of support for dynamic scene animation, and no traditional programming language constructs", and that VRML 2.0 avoided "language wars" by letting other programming languages talk to the scene through a Script node.[5]
In July 1996 the ISO/IEC JTC 1/SC 24 committee agreed to publish VRML 2.0 as Committee Draft 14772.[14] The result, ISO/IEC 14772-1:1997, was approved in December 1997 and became known as VRML97; it changed the wording and layout of the document to meet ISO requirements but did not change the functionality of VRML 2.0.[11] A second part, ISO/IEC 14772-2:2004, standardized the External Authoring Interface (EAI).[17] The Library of Congress notes that ISO/IEC 14772-1:1997 was reviewed and confirmed in 2021.[4]
Consortium and transition to X3D
The VAG planned the formation of a VRML Consortium in August 1996 and handed over all its responsibilities to it at a final meeting at Netscape in Mountain View on 12 December 1996.[14] Corporate members included Apple, Cosmo Software (an SGI company), Microsoft, IBM and Sony.[11] Pesce resigned from the consortium the day before its existence was officially announced and sent an "open letter to the VRML community", warning that "the Consortium might well represent the end of the democratic nature of our community". He told Wired News that the interim board included two companies that had tried to "hamstring VRML" and named one of them as Apple, which had its own QuickTime VR format. Consortium president Rikk Carey denied the accusations.[18]
In December 1998 the VRML Consortium widened its charter and renamed itself the Web3D Consortium. According to the Library of Congress, VRML stayed "essentially static" after 1997. The consortium began developing an enhanced successor, X3D, in 2001; it became the first edition of ISO/IEC 19775 in 2004 and was numbered version 3.0, continuing VRML's version sequence. X3D added geo-referencing, NURBS geometry and humanoid animation (H-Anim), defines an XML encoding alongside a Classic VRML encoding (ISO/IEC 19776-2), and includes an Immersive profile compatible with the functionality of VRML.[7]
Technical design
A VRML file is plain text and can be written in an ordinary text editor; like HTML it is platform independent, links to other resources by URL, and can embed images, video, sound and scripts.[11] The VRML97 specification lists six design criteria: authorability, composability, extensibility, capability of implementation, performance and scalability.[1]
| Property | VRML97 value |
|---|---|
| File extension | .wrl ("world"); gzip-compressed files may use .wrl.gz or .wrz[4] |
| MIME type | model/vrml; x-world/x-vrml for backward compatibility[4] |
| File header | #VRML V2.0 utf8 (VRML 1.0 files begin #VRML V1.0 ascii)[4][12]
|
| Scripting | Java and JavaScript bindings in Annexes B and C of the standard[5] |
| Standards | ISO/IEC 14772-1:1997 (functional specification and UTF-8 encoding); ISO/IEC 14772-2:2004 (External Authoring Interface)[17] |
Scene graph and nodes
A VRML world is a hierarchical scene graph (a directed acyclic graph) of nodes. A Shape node pairs geometry with an appearance. Geometry nodes include the primitives Box, Cone, Cylinder and Sphere, Text, ElevationGrid for terrain, Extrusion, and IndexedFaceSet, IndexedLineSet and PointSet for arbitrary shapes. Material nodes set diffuse, emissive and specular color and transparency, and ImageTexture, MovieTexture and PixelTexture map images or video onto surfaces.[5][4] Sound nodes embed spatialized (3D) audio together with the shapes they belong to.[5] Grouping nodes include Billboard, Collision, Switch and LOD, which selects between alternative versions of an object by viewer distance or frame rate.[5]
Two nodes connect a world to the web. Inline loads 3D content from another VRML file into the current world, while Anchor turns its child geometry into a hyperlink: clicking it replaces the scene with the world at the linked URL.[5]
Viewpoint nodes set the position, orientation and field of view of the virtual camera, and most worlds define several named viewpoints for easy navigation. The NavigationInfo node defines an avatar bounding box used for camera collision and eye height when terrain following is on, controls a default headlight, and switches between navigation styles such as WALK, EXAMINE and FLY.[5] A 2018 survey of web 3D notes that VRML already offered at least four navigation types: WALK, EXAMINE, FLY and NONE.[19]
Events, scripts and prototypes
VRML97 animation is event driven. Sensors detect the passage of time (TimeSensor), viewer proximity or visibility, and user input such as a mouse click on a shape (TouchSensor), and they emit time-stamped events. ROUTE statements connect those events to interpolators, which perform key-frame animation, and to fields of other nodes. Brutzman notes that the built-in sensors and interpolators were usually preferable to custom scripts for performance.[5] The Library of Congress lists the sensor nodes as Anchor, Collision, CylinderSensor, PlaneSensor, ProximitySensor, SphereSensor, TimeSensor, TouchSensor and VisibilitySensor, and notes that VRML 2.0 sound used WAV or MIDI files.[4]
The Script node lets Java or JavaScript code receive, process and send events. PROTO and EXTERNPROTO declarations create new node types from existing ones; an EXTERNPROTO refers to a definition stored at a remote URL so it does not have to be copied into every file.[5] Tony Parisi told NetscapeWorld in 1996 that "the real benefit of 2.0 is in the so-called PROTOs, the re-usable objects with behaviors".[15] The External Authoring Interface let Java applets in an HTML page send messages to and from an embedded VRML scene from outside it.[5]
Browsers and tools
VRML content was usually viewed in a plug-in installed in a 2D web browser such as Netscape or Internet Explorer.[5] Brutzman wrote in 1998 that "over twenty million VRML browsers have shipped with Web browsers".[5] In September 1996 NetscapeWorld called Netscape's Live3D "the most popular VRML browser", noted that it did not yet support VRML 2.0, and reported beta versions of Silicon Graphics' Cosmo Player and Sony's Community Place VRML 2.0 browsers.[15]
| Browser or toolkit | Developer (where documented) | Notes |
|---|---|---|
| WorldView | Intervista Software | Listed by the W3C in April 1995; built on Reality Lab; later distributed with Internet Explorer[6][13][9] |
| WebSpace | Silicon Graphics | Listed by the W3C in April 1995[6] |
| Live3D | Netscape | Described as the most popular VRML browser in 1996[15] |
| Cosmo Player | Silicon Graphics | VRML 2.0 browser, in beta in 1996[15] |
| Community Place | Sony | VRML 2.0 browser, in beta in 1996[15] |
| Blaxxun Contact | Plug-in released in 1995; became BS Contact in 2002[19] | |
| Cortona3D | VRML viewer and authoring tool, later adapted to WebGL[19] | |
| Octaga Player | Interactive 3D web presentations; later adapted to WebGL[19] | |
| InstantReality | VRML and X3D framework with VR and AR support[19] |
Gzip compression reduced VRML files to roughly 10 percent of their original size, according to NetscapeWorld.[15] The VAG issued further requests for proposals for a binary file format and an external interface after VRML 2.0 was released.[14]
Applications
The standard itself names engineering and scientific visualization, multimedia presentations, entertainment and educational titles, web pages and shared virtual worlds as application areas.[1] NetscapeWorld described 1996 uses such as 3D data visualization, product design and marketing, and multi-user worlds from companies such as Black Sun Interactive.[15]
Medical and scientific researchers adopted the format to share 3D models over the web. Warrick and Funnell of McGill University described in 1998 how VRML let "researchers, educators, and students" share anatomical models; they reconstructed the middle ear from histological and MRI sections, converted the models to VRML, and modified a VRML browser to render transparent surfaces.[20] In 2018 a team based at the University of Barcelona exported high-resolution angiography of the internal carotid artery to VRML before embedding it in an interactive 3D PDF.[21]
Multi-user VRML worlds were an early type of collaborative virtual environment. A project begun in 1999 recreated the São Miguel das Missões Jesuit mission ruins in Brazil from photogrammetric maps as a desktop multi-user community with chat, message boards and walk-throughs; the only requirement to join was "a web browser powered with any Virtual Reality Modeling Language (VRML) plug-in".[22] For large multi-user worlds, Brutzman described using the IEEE 1278.1 Distributed Interactive Simulation (DIS) protocol over multicast networking, and the dis-java-vrml working group was writing a public-domain DIS library in Java for multiple-entity VRML worlds.[5] Research use has continued: a 2024 paper in PeerJ Computer Science used VRML with Java and JavaScript scripts to build a virtual museum animation scene and reported frame rates consistently above 40 frames per second.[23]
Reception and decline
VRML had wide industry backing in the mid-1990s. Parisi later listed Netscape, Microsoft, Adobe, Silicon Graphics, Sun, Intel, Apple and IBM among its supporters, yet called it "a noble experiment, conceived with the best of intentions, that ultimately came up short". His explanation was that "we didn't have a market. The processing power and bandwidth required for quality 3D weren't in the average home."[8] In a 2015 interview he added that few people could create real-time 3D content or publish it to the Internet, and that "You had to install a plugin... there was a lot of friction to having people get the 3D experience in the browser."[9]
Academic reviews reach a similar conclusion. Potenziani and colleagues wrote in 2018 that VRML and X3D were designed basically as file and scene formats and needed additional software to be displayed in web browsers, and that "this last issue was probably the biggest hurdle to the success of that generation of solutions". Citing Raggett's 1994 proposal, they also described VRML as "a seminal work for the declarative Web3D approach", an approach that dominated many web 3D systems from the late 1990s to the early 2000s, and dated VRML's replacement by X3D to 2004.[19] The Library of Congress states that most adopters have moved to X3D, WebGL or other formats.[4]
Legacy
The goal of following a link straight into a 3D world was revived with browser-based VR. A 2015 Road to VR article quoted Parisi, then vice president of platform technology at WEVR, as asking "Why can't we just click a link, or type a URL, and instantly enter virtual reality? Why download and install apps?"[24] In a 2015 interview he described connecting a web browser to headsets such as the Oculus Rift, so that a user could click a URL and enter a VR experience with "no download, no friction".[9] In 2016 he pointed to WebGL ("hardware-accelerated 3D in a browser... with no additional download"), the WebVR browser APIs and glTF, "the new portable 3D file format that is like JPEG, but for 3D", as the pieces that finally made the web and VR converge.[8]
The format itself survives through X3D, whose Classic VRML encoding keeps VRML-style syntax, and through ISO/IEC 14772-1:1997, which ISO reviewed and confirmed in 2021.[7][4] The Library of Congress holds a small number of VRML files in its collections.[4]
Version history
| Date | Version or event |
|---|---|
| May 1994 | Labyrinth "Cyberspace" paper and Raggett's proposal presented at the First International Conference on the World-Wide Web, Geneva[10][2] |
| 2 November 1994 | First draft of VRML 1.0[3] |
| 26 May 1995 | VRML 1.0 specification[3] |
| 20-23 August 1995 | First meeting of the VRML Architecture Group[14] |
| 29 January 1996 | VRML 1.0C (clarifications)[3] |
| 18 March 1996 | Final poll on VRML 2.0 proposals; Moving Worlds favored by 74 percent[16] |
| 4 August 1996 | VRML 2.0 specification released at SIGGRAPH 96[14] |
| December 1996 | VRML Consortium takes over from the VAG[14][18] |
| December 1997 | ISO/IEC 14772-1:1997 (VRML97) approved[11] |
| December 1998 | VRML Consortium renamed Web3D Consortium[7] |
| 2004 | X3D published as ISO/IEC 19775 (version 3.0); ISO/IEC 14772-2:2004 (External Authoring Interface)[7][17] |
See also
References
- ↑ 1.0 1.1 1.2 "The Virtual Reality Modeling Language, ISO/IEC 14772-1:1997, Introduction". Web3D Consortium. 1997. https://www.web3d.org/documents/specifications/14772/V2.0/part1/introduction.html. Retrieved 2026-10-04.
- ↑ 2.0 2.1 2.2 David Raggett (1994). "Extending WWW to Support Platform Independent Virtual Reality". W3C. https://www.w3.org/People/Raggett/vrml/vrml.html. Retrieved 2026-10-04.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Gavin Bell, Anthony Parisi, Mark Pesce (1996-01-29). "The Virtual Reality Modeling Language Version 1.0C Specification". VRML Architecture Group. https://web.archive.org/web/19970212083935/http://vrml.wired.com/vrml10c.html. Retrieved 2026-10-04.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 "Virtual Reality Modeling Language Family". Sustainability of Digital Formats. Library of Congress. 2024-05-01. https://www.loc.gov/preservation/digital/formats/fdd/fdd000602.shtml. Retrieved 2026-10-04.
- ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 5.11 5.12 5.13 5.14 Don Brutzman (1998-06). "The Virtual Reality Modeling Language and Java". Communications of the ACM, vol. 41, no. 6, pp. 57-64. doi:10.1145/276609.276620. https://faculty.nps.edu/brutzman/vrtp/docs/vrmljava.pdf. Retrieved 2026-10-04.
- ↑ 6.0 6.1 6.2 6.3 "VRML Virtual Reality Modeling Language". W3C. 1995-04-17. https://www.w3.org/MarkUp/VRML/. Retrieved 2026-10-04.
- ↑ 7.0 7.1 7.2 7.3 7.4 "Extensible 3D (X3D) File Format Family". Sustainability of Digital Formats. Library of Congress. 2025-02-19. https://www.loc.gov/preservation/digital/formats/fdd/fdd000490.shtml. Retrieved 2026-10-04.
- ↑ 8.0 8.1 8.2 Tony Parisi (2016-08-23). "25 Years Later After The Crash, Web and VR Are Finally Converging For Real". UploadVR. https://www.uploadvr.com/third-times-charm/. Retrieved 2026-10-04.
- ↑ 9.0 9.1 9.2 9.3 9.4 9.5 9.6 9.7 Matthew Terndrup (2015-04-08). "Flashback: Tony Parisi on Co-Creating the Virtual Reality Markup Language (VRML) for the Web in the 1990s". UploadVR. https://www.uploadvr.com/flashback-tony-parisi-on-co-creating-the-virtual-reality-markup-language-vrml-for-the-web-in-the-1990s/. Retrieved 2026-10-04.
- ↑ 10.0 10.1 10.2 Mark D. Pesce, Peter Kennard, Anthony S. Parisi (1994-05). "Cyberspace". First International Conference on the World-Wide Web (WWW94). IW3C2. https://archives.iw3c2.org/www1/PdfWWW94/mpesce.pdf. Retrieved 2026-10-04.
- ↑ 11.0 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 "A Guide to VRML 2.0 - 1. Introduction". AGOCG. https://web.archive.org/web/20060214032919/http://www.agocg.ac.uk/train/vrml2rep/part1/guide1.htm. Retrieved 2026-10-04.
- ↑ 12.0 12.1 Gavin Bell, Anthony Parisi, Mark Pesce (1995-05-26). "The Virtual Reality Modeling Language - Version 1.0 Specification". Graphcomp. https://graphcomp.com/info/specs/vrml10.html. Retrieved 2026-10-04.
- ↑ 13.0 13.1 Erik Davis (1995-07-01). "Technopagans". Wired. https://www.wired.com/1995/07/technopagans/. Retrieved 2026-10-04.
- ↑ 14.0 14.1 14.2 14.3 14.4 14.5 14.6 14.7 "VRML Architecture Group". VRML Architecture Group. https://web.archive.org/web/19970212083709/http://vrml.wired.com/. Retrieved 2026-10-04.
- ↑ 15.0 15.1 15.2 15.3 15.4 15.5 15.6 15.7 Adrian Scott (1996-09). "VRML 2.0 Update: What are the issues, and where do we go from here?". NetscapeWorld. http://www.mitra.biz/press/199609_netscapeworld.htm. Retrieved 2026-10-04.
- ↑ 16.0 16.1 "VRML 2.0 FINAL Polling Results". VRML Architecture Group. 1996-03-18. https://web.archive.org/web/19970503004420/http://vrml.wired.com/polling/Results.html. Retrieved 2026-10-04.
- ↑ 17.0 17.1 17.2 "The Virtual Reality Modeling Language (VRML97)". Web3D Consortium. https://www.web3d.org/documents/specifications/14772/V2.0/index.html. Retrieved 2026-10-04.
- ↑ 18.0 18.1 Susan Kuchinskas (1996-12-10). "VRML Co-Creator Protests Consortium". Wired News. https://web.archive.org/web/19981202055113/http://www.wired.com/news/story/930.html. Retrieved 2026-10-04.
- ↑ 19.0 19.1 19.2 19.3 19.4 19.5 Marco Potenziani, Marco Callieri, Matteo Dellepiane, Roberto Scopigno (2018). "Publishing and Consuming 3D Content on the Web: A Survey". Foundations and Trends in Computer Graphics and Vision, vol. 10, no. 4, pp. 244-333. https://doi.org/10.1561/0600000083. Retrieved 2026-10-04.
- ↑ P. A. Warrick, W. R. J. Funnell (1998-06). "A VRML-based anatomical visualization tool for medical education". IEEE Transactions on Information Technology in Biomedicine, vol. 2, no. 2, pp. 55-61. https://doi.org/10.1109/4233.720523. Retrieved 2026-10-04.
- ↑ M. Valera-Melé, A. Puigdellívol-Sánchez, M. Mavar-Haramija, J. A. Juanes-Méndez, L. San-Román, M. de Notaris, A. Prats-Galino (2018-03-05). "A Novel and Freely Available Interactive 3d Model of the Internal Carotid Artery". Journal of Medical Systems, vol. 42, no. 4, art. 72. https://doi.org/10.1007/s10916-018-0919-4. Retrieved 2026-10-04.
- ↑ S. R. dos Santos, L. S. Fraga (2002-10). "Using a multi-user desktop-based virtual reality system to recreate the São Miguel das Missões ruins". CyberPsychology and Behavior, vol. 5, no. 5, pp. 471-479. https://doi.org/10.1089/109493102761022896. Retrieved 2026-10-04.
- ↑ Y. Zhu, S. Xie (2024-11-13). "Simulation methods realized by virtual reality modeling language for 3D animation considering fuzzy model recognition". PeerJ Computer Science, vol. 10, e2354. https://doi.org/10.7717/peerj-cs.2354. Retrieved 2026-10-04.
- ↑ Sophia Dominguez (2015-11-16). "4 Thoughts on Carmack's 'VrScript' from Tony Parisi, Creator of VRML". Road to VR. https://www.roadtovr.com/4-thoughts-on-carmacks-vrscript-from-tony-parisi-creator-of-vrml/. Retrieved 2026-10-04.