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One area that can be exploited in higher education is the extensive access that these establishments have to the WWW. The Virtual Reality Modelling Language (VRML) enables world builders to create and explore three-dimensional worlds on the WWW. VRML is a platform-independent language for virtual reality scene design based on the OpenInventor format. Various viewers or "plug-in" VRML browsers can be used to explore a virtual environment (e.g. CosmoPlayer, Liquid Reality, Community Place browsers).
Currently, the latest version of VRML (VRML 97) is in the process of being submitted as an ISO standard.
The first point of call for anyone interested in VRML models on the WWW should be the VRML Repository. The repository is maintained at the San Diego Supercomputer Center (SDSC) and provides a comprehensive source of information. Categories of information include hardware and software which includes a comprehensive list of browsers, a documentation section, a worlds section, sounds and textures section and a miscellaneous section. The worlds, sounds and textures category contains links to a number of sites where VRML models and worlds can be freely downloaded. These include:
A commercial site which contains a number of VRML models that can be viewed. There are also a large number of models that can be purchased from this commercial site.
This site contains almost 400 VRML models grouped into 32 categories including toys, vehicles, military and music. Each model has a small thumbnail image that can be viewed, the name of the file and the file size. Also provided is a 3D Mall, a 3D version of the object catalogue and the facility for the user to upload their own models if they wish.
The repository also provides a link to the UK VR-SIG Object Archive which contains a number of VRML models. It should also be noted that many of the model databases mentioned in section 5.1 also contain downloadable VRML models and information pertaining to this file format.
STEP is based on an initiative started in the mid-1980s by the US PRO IGES/PDES Organization (IPO). The basis of STEP was developed from the Product Data Exchange Specification (PDES), the specification being forwarded to the international community in 1988. STEP was approved as an international standard (IS) in 1994.
The goal of STEP is to provide a representation of product information, mechanisms and definitions that will allow product data to be exchanged between different computer systems and environments. In this way, the information can be updated and transferred throughout the entire product lifecycle which will include design, manufacture, utilisation, maintenance and disposal.
STEP is organised into a series of separately published parts. In order to specify the product information, STEP uses the specification language EXPRESS to enable consistency and precision of representations.
The overall objective is to provide a mechanism for describing product data that is platform independent and can be used throughout the entire lifecycle of the product. Therefore, STEP is suitable for neutral file exchange and also as a basis for implementing and sharing product databases and archiving.
The use of STEP has been approved by more than 20 countries world-wide.
Development tools for VR systems have moved on from the early data driven, and ultimately deterministic systems to a more intuitive event driven architecture. Furthermore, there is a migration to visual programming techniques both in terms of the model definition and world definition (e.g. Steed 1996). This may signal a future amalgamation of modelling and world builder languages.
With the web comes possibilities for model sharing, already being exploited by various systems (Division’s Universal Product and VRML 97). However, with these developments comes an ever increasing need for standardisation. Certainly, multi-party interaction will drive the need for a standard. Presently there are few systems which cater adequately for this. Although there is a trend toward standardisation within the hardware domain (e.g. PC graphics cards, sound cards, etc.), ultimately world design methodologies are still, in many ways, product dependent.
Section 5.1 of this report indicates that there are a vast number of 3D models contained in databases on the world wide web that are relatively easy to access. This suggests that it is not necessary to consider the formation of an AGOCG model database. This is due to several factors:
A possible alternative may be to provide a model database links web site for the membership. This would essentially take the form of section 5.1 of this document. Using this method links to, and a review of, appropriate databases can be provided. If the information is correctly structured, members can then identify sites and collections of models that are appropriate for their own discipline.
The set-up time and maintenance of such a site is considerably reduced, as is the demand for computational resources, providing a very cost-effective solution for AGOCG.
Graphics Multimedia Virtual Environments Visualisation Contents