REVIMA is a virtual reality system for maintainability simulation in Aeronautics. It comprises both hardware and software developments, plus system integration. REVIMA required the design of a new haptic system. It is used both to track hand movements and to return force feedback that provides the sensation of working with a physical mock-up. The main software modules are: image generation, collision detection and control. System integration is based on two LAN connected PCs that share the different tasks and data. The visualization module has been built using low-cost graphic systems, and we have thoroughly analysed this problem to achieve a drawing frame rate acceptable for simulation analysis. The models comprise more than two thousand different elements that require about two million polygons to describe their shapes. Different organization strategies have been tested in order to achieve the real simulation goal. We also present the different visualization algorithms we have used.

Nous présentons ici les mécanismes que nous implémentons au-dessus de la plate-forme OpenMASK dans le but de faciliter l'interaction dans les mondes virtuels 3D, en particulier lorsqu'ils sont peuplés d'objets à forte composante technique, c'est-à-dire imposant de fortes contraintes lors des interactions 3D. Nous présentons les mécanismes génériques utilisés pour permettre d'interagir avec des objets ainsi que pour obtenir des informations permettant de visualiser le plus explicitement possible les possibilités d'interactions offertes par les objets ainsi que les interactions effectivement en cours. Nous terminons par la façon de rendre explicite les interactions des autres utilisateurs dans le cas des univers 3D coopératifs.

We present here a visualization environment for the train industry, where engineers, designers or executives can discuss and analyze visual, aesthetics and ergonomic issues of a train model before it is built. Instead of building a full-size real model, which is not too practical at all regarding design modifications, a virtual model is built in the digital realm, thus taking advantage of the flexibility it offers while keeping costs at approximately one third of the real model. The environment is based on a low cost, PC-based, CAVE-like architecture, (which we have named CLS, or CAVE-Like System) and combines static and dynamic computer generated imagery, both with and without stereoscopy for 3D visualization, as well as Augmented Virtuality techniques for the integration of the train with its environment. The system has already been tested and used by the Spanish companies Renfe and CAF in the design of the new Civia train.

Nous présentons dans cet article quelques réflexions sur l'utilisation de la Réalité Virtuelle et des techniques adjacentes en conception de produits. La Réalité Virtuelle est présentée comme un outil d'aide à la décision en milieu industriel, mais aussi comme un facteur nécessaire auprès des futurs utilisateurs de produits. Cet article s'appuie sur une bibliographie qui consiste à positionner la Réalité Virtuelle dans un processus de conception. Il positionne aussi un ensemble d'articles récents, développés au cours de la conférence Virtual Concept 2002.

Les espaces de visualisation immersive se développent dans de nombreux secteurs de la recherche et de l'industrie où ils s'intègrent de plus en plus dans les chaînes de décision, de développement ou de production. Se pose alors la question délicate de l'utilisation optimale des applications logicielles dans ces environnements. Dans cette étude, nous définirons tout d'abord une séance de travail immersive et ses contraintes en termes d'interaction. Nous passerons ensuite en revue les nombreuses solutions matérielles et logicielles déjà proposées pour repousser les limites du modèle du clavier et de la souris. Puis, à partir d'une synthèse des besoins industriels de commande des applications, nous proposerons d'imiter un modèle d'interacteur très usuel qui a fait ses preuves en utilisation domestique : la télécommande. Nous présenterons enfin le prototype que nous avons implémenté sur la base d'un assistant personnel numérique de type PocketPC connecté à un réseau radio sans fil et la bibliothèque de classes C++ associée qui permet de l'utiliser très rapidement dans n'importe quelle application.

Virtual reality shows to be of use in several domains of manufacturing as a complementary tool to CAD/CAM environment. Design review is one of the very first application of VR in product design, but assembly/disassembly studies are also existing though they require some more specific work. But it can also be useful beyond the scope of common CAD software such as ergonomic studies. We will show an example from the RNTL PERF-RV project where we study the ergonomics of a car dashboard and more specifically of a push-button. We will discuss the issues raised by studying ergonomics thanks to Virtual Reality and force-feedback systems which are both hardware and software.

The teamwork characterizes the early stages of the product development process. The teamwork in these early stages is characterized by simultaneous writing and sketching. Since the work is done on paper a later use of the generated ideas with computer programs is hindered. This represents a break in the logical concatenation of the product development process and thus results in a loss of information. This implies that it is necessary to provide the group with a tool that collects the information already during writing and sketching. A technical workplace is described that uses techniques from virtual reality to allow a real teamwork in these early stages. Using picture acquisition and color separation techniques different pencils can be detected simultaneously in real time on a horizontal surface. Since only active parts are detected by the picture acquisition no quantization errors can occur caused by other objects on the surface like paper, elbow or hands. The realized teamwork space offers an A1-size work area onto which a simultaneous input is possible with four pens of different color. For the construction of the device a material has to be evaluated that is suitable for a back-projection.

Le travail présenté dans cet article est relatif à l'intégration d'une interface à retour d'efforts dans un environnement de simulation. Après une analyse de l'existant dans le domaine, des conditions d'intégration et des applications potentielles, nous présentons la solution retenue et les étapes de développement. Les éléments de modélisation nécessaires à la manipulation d'objets, de mannequins et de robots à l'aide du Phantom Desktop sont particulièrement développés dans ce papier. Nous montrerons également comment le retour d'effort est géré par l'application. Cette étude a été concrétisée par le développement du module eM-Virtual Desktop associé au produit eM-Workplace de la société Tecnomatix. Le module développé est testé actuellement par un constructeur automobile européen.

Today's businesses continually search for ways to increase productivity. To achieve this goal, shorter product development cycles and shorter manufacturing times are required. In both cases, problems that may arise during development must be identified much faster. In product development, this is done using virtual prototypes that can be easily duplicated and shared between everyone involved. In addition to this product design process, the stability of the manufacturing process and the resulting product quality ultimately determine the product's profitability. Therefore the manufacturing concepts of a new product can best be demonstrated using Virtual Manufacturing. The subset of Virtual Manufacturing where material properties of the product and machine tools and the physics of the process are investigated is called Virtual Process Engineering. Virtual Process Engineering utilizes Finite Element Methods (FEM) and simulations for the computation of the manufacturing process and Virtual Reality (VR) for quick and intuitive examination of the computation results.

VIRTOOL is an application that is part of the European Union supported project “Virtual Manipulation to Simulate Machine-Tool Processes” (VIRTOOL, CRAFT-1999-70292). The application is being developed by a consortium of two industrial enterprises (Alecop, IMH) and three partners in research and higher education (CEIT, TUD, ACM) from four European countries. The objective of this project is to design and develop a computer-supported learning environment for machine-tool processes by using interactive 3D graphics and virtual reality techniques. An integral part of this software will be an easy to use construction tool for the development of new 3D simulation models of machine-tools with the supporting learning material, which is based on a general instructional design model.

Virtual reality simulations of maintenance operations are a key simulation to improve the performance and quality of products. Real-time requirements of virtual reality systems face difficulties when coping with flexible components exhibiting strong non-linear behaviour. To this end, an interactive system incorporating mechanical models of flexible parts behaviour is described in the present paper. The approach proposed will be used as a basis to the simulation of flexible parts in a virtual reality environment for the evaluation of assembly operations. First of all, the study of current assembly planning systems based on the real-time approaches is performed. Secondly, a new system integrating real-time and interactive mechanical simulation approaches is proposed. An adequate simulation of the flexible components to estimate the assemblability in a virtual reality is discussed. This is especially true when flexible parts are subjected to large displacements. Finally, the example of the interactive mechanical behaviour model used into an assembly context for the virtual reality simulation environments is represented.

This paper addresses the positioning and identification of markers for 3D tracking within Virtual Reality (VR) applications. Many VR applications need to know the position and the orientation of the body of users in order to make possible intuitive user interactions as stereoscopy calculation, navigation control or gesture dialog. This work is based on infrared capture device that does not need to be physically dependent with tracked objects. During an acquisition, some markers could be occluded by objects or not visible by some cameras. This paper proposes a new solution that finds the position of the occluded markers or at least limits the consequences of oclusion. The aim is to minimise the effects of oclusion by an optimal distribution of the markers on the objects. It also uses a fast and robust markers identification algorithm. The global approach is based on the association of markers distribution with their identification, in order to optimise the number of visible markers.