3D virtual environments. Typology and interoperability

3D virtual environments are virtual reality applications which, over the years, have gained in number and diversity of uses. This technology has found applications in a wide range of fields, from entertainment to high-precision professional applications. Their diversity and sheer number pose a problem for which there is no universal solution: it is impossible to communicate from one virtual environment to another. It is not only extremely difficult to exchange data between two virtual environments, but also to access several virtual environments via a single client application.

This state of affairs poses a number of problems that are holding back the spread and adoption of 3D virtual environments:

• data reuse. The impossibility of directly exchanging and sharing data from one virtual environment to another hinders the reuse of data and, more specifically, virtual environment content. Indeed, although there is a wide range of tools available for producing 3D content, their handling is often not very intuitive. It is therefore very interesting to be able to reuse existing models, as their production is a costly and time-consuming task;

• component reuse and interchangeability. As it is virtually impossible to reuse 3D content directly, the same applies to the software components used to generate the virtual environment. These are compatible with a small subset of other components and 3D content, which limits their reusability for another virtual environment. As a result, it is often necessary to develop new components for each virtual environment, which further increases their cost and production time;

• the use of conversion. A commonly used solution for reusing content and components is to convert the data used, but conversion is often synonymous with errors and data loss, which can render converted content unusable;

• porting problems. The lack of interoperability also poses a problem when a virtual environment needs to be ported to another system (new client or new terminal);

• accessibility issues. 3D virtual environments are generally accessed via their own client application. To access another virtual environment, it is necessary to use another client application.

Interoperability solves all these problems, increasing and simplifying the use of 3D virtual environments.

The first part of this article presents a typology of 3D virtual environments and the properties that characterize them.

The second part details the various components of 3D virtual environments, 3D content and the software components needed to render content....