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Item Elasticity-based Clustering for Haptic Interaction with Heterogeneous Deformable Objects(The Eurographics Association, 2017) Gouis, Benoît Le; Marchal, Maud; Lécuyer, Anatole; Arnaldi, Bruno; Fabrice Jaillet and Florence ZaraPhysically-based simulation of heterogeneous objects remains computationally-demanding for many applications, especially when involving haptic interaction with virtual environments. In this paper, we introduce a novel multiresolution approach for haptic interaction with heterogeneous deformable objects. Our method called "Elasticity-based Clustering" is based on the clustering and aggregation of elasticity inside an object, in order to create large homogeneous volumes preserving important features of the initial distribution. The design of such large and homogeneous volumes improves the attribution of elasticity to the elements of the coarser geometry. We could successfully implement and test our approach within a complete and real-time haptic interaction pipeline compatible with consumer-grade haptic devices. We evaluated the performance of our approach on a large set of elasticity configurations using a perception-based quality criterion. Our results show that for 90% of studied cases our method can achieve a 6 times speedup in the simulation time with no theoretical perceptual difference.Item Ray-Traced Collision Detection: Interpenetration Control and Multi-GPU Performance(The Eurographics Association, 2013) Lehericey, Francois; Gouranton, Valérie; Arnaldi, Bruno; Betty Mohler and Bruno Raffin and Hideo Saito and Oliver StaadtWe proposed in [LGA13] an iterative ray-traced collision detection algorithm (IRTCD) that exploits spatial and temporal coherency and proved to be computationally efficient but at the price of some geometrical approximations that allow more interpenetration than needed. In this paper, we present two methods to efficiently control and reduce the interpenetration without noticeable computation overhead. The first method predicts the next potentially colliding vertices. These predictions are used to make our IRTCD algorithm more robust to the above-mentioned approximations, therefore reducing the errors up to 91%. We also present a ray re-projection algorithm that improves the physical response of ray-traced collision detection algorithm. This algorithm also reduces, up to 52%, the interpenetration between objects in a virtual environment. Our last contribution shows that our algorithm, when implemented on multi-GPUs architectures, is far faster.Item Roles in Collaborative Virtual Environments for Training(The Eurographics Association, 2015) Claude, Guillaume; Gouranton, Valérie; Arnaldi, Bruno; Masataka Imura and Pablo Figueroa and Betty MohlerIn this paper we present a novel approach to role modelling for Collaborative Virtual Environments with an Action Oriented Scenario Engine. Our role model is able to take into account different data about the actions such as the abilities, rights or resources required by an actor to determine whether he or she can execute an action. Furthermore, it considers that any data about an actor can have an influence on his or her role in the simulation. We provide also a team organisation model to define the impacts of the rules of the team on the role of the actors as suggested by the role theory. To illustrate our work, we used our model in a Collaborative Virtual Environment for the Training of a neurosurgery procedure.Item Short Paper: #SEVEN, a Sensor Effector Based Scenarios Model for Driving Collaborative Virtual Environment(The Eurographics Association, 2014) Claude, Guillaume; Gouranton, Valerie; Berthelot, Rozenn Bouville; Arnaldi, Bruno; Takuya Nojima and Dirk Reiners and Oliver StaadtIn this paper we present #SEVEN, a sensor effector model that enables the execution of complex scenarios for driving Virtual Reality applications. #SEVEN is based on an enhanced Petri net model which is able to describe and solve intricate event sequences. Our model also proposes several useful features for the design of collaborative scenarios for Collaborative Virtual Environments such as versatile roles and Activity Continuum.We also illustrate its usage it by describing a demonstrator that presents an implementation of our model.Item Authoring AR Interaction by AR(The Eurographics Association, 2019) Lécuyer, Flavien; Gouranton, Valérie; Reuzeau, Adrien; Gaugne, Ronan; Arnaldi, Bruno; Kakehi, Yasuaki and Hiyama, AtsushiThe demand for augmented reality applications is rapidly growing. In many domains, we observe a new interest for this technology, stressing the need for more efficient ways of producing augmented content. Similarly to virtual reality, interactive objects in augmented reality are a powerful means to improve the experience. While it is now well democratized for virtual reality, interactivity is still finding its way into augmented reality. To open the way to this interactive augmented reality, we designed a new methodology for the management of the interactions in augmented reality, supported by an authoring tool for the use by designers and domain experts. This tool makes the production of interactive augmented content faster, while being scalable to the needs of each application. Usually in the creation of applications, a large amount of time is spent through discussions between the designer (or the domain expert), carrying the needs of the application, and the developer, holding the knowledge to create it. Thanks to our tool, we reduce this time by allowing the designer to create an interactive application, without having to write a single line of code.Item From Observations to Collaborative Simulation: Application to Surgical Training(The Eurographics Association, 2016) Claude, Guillaume; Gouranton, Valérie; Caillaud, Benoit; Gibaud, Bernard; Jannin, Pierre; Arnaldi, Bruno; Dirk Reiners and Daisuke Iwai and Frank SteinickeIn surgical training, Virtual Reality systems are mainly focused on technical surgical skills, leaving out procedural aspects. Our project aims at providing a novel approach to the use of Virtual Reality addressing this point. In our project, we propose an innovative workflow to integrate a generic model of the procedure, generated from real case surgery observation, as the scenarios model in the virtual reality training system. In this article we present how the generic procedure model is generated and its integration in the virtual environment.Item STORM: a Generic Interaction and Behavioral Model for 3D Objects and Humanoids in a Virtual Environment(The Eurographics Association, 2007) Mollet, Nicolas; Gerbaud, Stéfanie; Arnaldi, Bruno; Bernd Froehlich and Roland Blach and Robert van LiereWe present in this paper research focused on interaction and behavior specification for 3D objects in general, including humanoids. This research is conducted in the context of a collaboration with Nexter-Group (a French military manufacturer) in order to introduce Virtual Reality (VR) in maintenance training. The use of VR environments for training is strongly stimulated by important needs of training on sensitive equipment, sometimes fragile, unavailable, costly or dangerous. Nevertheless, for the development of such applications, the re-use of existing developments is a major issue. Our research is focused on models that have been designed to achieve this reusability and standardization for the efficient development of new virtual environments. In particular, we defined a new generic model named STORM, used to describe reusable behaviors for 3D objects in general, including humanoids, and reusable interactions between those objects.Item A New Adaptive Data Distribution Model for Consistency Maintenance in Collaborative Virtual Environments(The Eurographics Association, 2010) Fleury, Cédric; Duval, Thierry; Gouranton, Valérie; Arnaldi, Bruno; Torsten Kuhlen and Sabine Coquillart and Victoria InterranteEnsuring that all the users see the same state of a Collaborative Virtual Environment (CVE) at the same time is very important to provide effective collaboration between these users. Absolute consistency is nearly impossible to achieve because it would prejudice the system responsiveness during user interactions. Consequently, existing solutions make a trade-off between consistency and system responsiveness according to their own requirements. We propose a new adaptive data distribution model that is able to dynamically change data distribution according to application requirements, user's actions and functions that virtual objects fulfill in the virtual environment. Our solutions can deal with several kinds of requirements imposed by various applications and network constraints. The choice of the data distribution can be made at the object level because all the objects of a virtual environment do not necessarily have the same need for consistency. Finally, we evaluate this model for collaborative scientific data visualization using a client/server architecture and HTTP/HTTPS connections. The results show that our model can minimize both interaction latency and gap in consistency between users, so it enables users to always perform real-time interactions in a consistent CVE.Item The Stretchable Arms for Collaborative Remote Guiding(The Eurographics Association, 2015) Chénéchal, Morgan Le; Duval, Thierry; Gouranton, Valérie; Royan, Jérome; Arnaldi, Bruno; Masataka Imura and Pablo Figueroa and Betty MohlerThe help of a remote expert to guide an agent in performing a physical task can be advantageous in many ways: saving time and money by avoiding travel, and thus increasing the rate of intervention. In many situations, the remote expert wishes to guide the agent by first placing him in the correct location to achieve the task. However, as the agent is not a robot, the expert can not use a location controller to place the agent. Instead, interaction techniques must enable the expert to achieve this task before physical manipulation guidance. In this paper, we propose a novel interaction technique for remote guiding based on arm gestures. First, the remote expert (using a VR setup) virtually collocates himself with the agent (using an AR setup), then controls virtual arms collocated with both users' shoulders. Second, if the expert starts to move forward to grasp a virtual object, the virtual arms start to stretch in order to keep the shoulders' collocation on the agent's side. This metaphor allows the agent to understand the direction of the expert's motion easily while preserving the naturalness of the interaction and avoiding the use of a frustum to represent the expert's head location.Item Can You Find Your Way? Comparing Wayfinding Behaviour Between Reality and Virtual Reality(The Eurographics Association, 2023) Goupil, Vincent; Arnaldi, Bruno; Argelaguet, Ferran; Michaud, Anne-Solène; Gouranton, Valérie; Jean-Marie Normand; Maki Sugimoto; Veronica SundstedtSignage is an essential element in finding one's way and avoiding getting lost in open and indoor environments. Yet, designing an effective signage system for a complex structure remains a challenge, as some buildings may need to communicate a lot of information in a minimum amount of space. Virtual reality (VR) provides a new way of studying human wayfinding behaviour, offering a flexible and cost-effective platform for assessing the efficiency of signage, especially during the design phase of a building. However, it is not yet clear whether wayfinding behaviour and signage interpretation differ between reality and virtual reality. We conducted a wayfinding experiment using signage with 20 participants who performed a series of tasks in virtual and real conditions. Participants were video-recorded in both conditions. In addition, oral feedback and post-experiment questionnaires were collected as supplementary data. The aim of this study was to investigate the wayfinding behaviour of a user using signs in an unfamiliar real and virtual environment. The results of the experiment showed a similarity in behaviour between both environments; regardless of the order of passage and the environment, participants required less time to complete the task during the second run by reducing their mistakes and learning from their first run.