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VRML - Virtual Reality Modeling Language

VRML is to 3D graphics what HTML is to text: it is a common format that can be displayed on any computer using a standard WWW browser (For instance Netscape or Explorerequipped with a viewer, see the VRML repository) or using a standalone viewer.

It allows the user to click on links to other objects (hypertext mark-up). As a trivial example, the following file displays two spheres in 3D, with the address of another VRML object (bcc.wrl) anchored to the first sphere.

#VRML V1.0 ascii
WWWAnchor{name "http://www.ill.fr/dif/vrml/bcc.wrl" Sphere{}}
Translation {translation 1 1 1 } Sphere {}
Complex 3D crystal structures can be described in VRML, including space filling, ball-and-stick, co-ordination polyhedrae etc.. They can be explored from the inside with full interactivity. The translation of three dimensional crystallographic objects into VRML is facilitated by way of converters able to change a conventional set of coordinates into a standard .wrl file. There is no need to speak VRML like a specialist.

VRML Authoring for Crystallographers: The tool market is growing with either downloadable converters such as pdb2vrml, xtal-3d, CRYSTAL, MOLDA and STRUVIR or online builders (send your data and receive the corresponding .wrl file in return) such as Builder 1.2 for membranes, PDB to VRML, the Crystal Packing Visualization by VRML system (Tai Y. Fu and Yu Wai Chen, J. Appl. Cryst. 1996, 29, 594-597), the Chemical VRML Generation Service and xtal-3d which is able to access to the Inorganic Crystal Structure Database.

Example VRML Files: A non-exhaustive list includes Chemical Examples, 3D Scenarios of Biomolecules, Silicates (aluminosilicates and zeolites announced), the ILL's Gallery, an Introduction to Crystal Structures, the JICST Crystal Structure Database, 6-connected 3D nets, the IUMSC Database, Biological Macromolecules.... Some of them were built using the above converters.

General Documentation: It is recommended to read the FAQ, to visit the VRML repository and its list of Browsers, to subscribe to the VRML Forum, to respect the VRML versions 1.0 and 2.0 specifications, to consider the SGI site and the Yahoo selection, to read and post messages to the comp.lang.vrml Newsgroup.

Conclusion: As a general tool for 3D visualization in crystallography VRML was unexpected. The real usefulness of current or future possibilities like 3D mark-up, multi-user connections, links to sound or other media is an open question. Not everything that uses VRML will necessarily be an Internet application. Producers of drawing programs for crystallography should consider at least offering a .wrl output file option to their users. Availability of free PC converters should boost VRML applications in crystallography. Finally, without the possibility to save high quality 2D projections of a selected 3D view and to print them, crystallographers at large might not adopt the baby. At the moment quality depends on your maximum screen resolution.

What is New since IUCr XVII ?

[Index] - January, 4, 2000 - © Alan Hewat and Armel Le Bail - Not to be copied or reproduced without permission