Geometry deformation for reducing cybersickness in VR

Virtual reality (VR) technologies became more and more widespread for a couple of years as they got more and more mature. The accessibility to VR highly increased thanks to recent low-cost commercial VR head mounted display systems and easy-to-use development toolkits. One important and well-studied human perception issue is related to motion sickness or cybersickness. In this paper we are dealing with case when users feel a visually induced induced self-motion that are not felt through their vestibular systems. This incoherent movement perception provokes cybersickness to the users. To tackle this issue, we present in this paper a novel method to reduce cybersickness through reducing visually induced self-motion by processing geometrically the virtual scene while navigating. The first prototype of geometry deformation applied on virtual building appearing in the peripheral vision of user has been implemented and experimented. The feedback from the experiment participants shows that the visually induced self-motion is reduced and the navigation quality and presence level are guaranteed

Merging enriched Finite Element triangle meshes for fast prototyping of alternate solutions in the context of industrial maintenance

A new approach to the merging of Finite Element (FE) triangle meshes is proposed. Not only it takes into account the geometric aspects, but it also considers the way the semantic information possibly associated to the groups of entities (nodes, faces) can be maintained. Such high level modification capabilities are of major importance in all the engineering activities requiring fast modifications of meshes without going back to the CAD model. This is especially true in the context of industrial maintenance where the engineers often have to solve critical problems in very short time. Indeed, in this case, the product is already designed, the CAD models are not necessarily available and the FE models might be tuned. Thus, the product behaviour has to be studied and improved during its exploitation while prototyping directly several alternate solutions. Such a framework also finds interest in the preliminary design phases where alternative solutions have to be simulated. The algorithm first removes the intersecting faces in an n-ring neighbourhood so that the filling of the created holes produces triangles whose sizes smoothly evolve according to the possibly heterogeneous sizes of the surrounding triagles. The holefilling algorithm is driven by an aspect ratio factor which ensures that the produced triangulation fits well the FE requirements. It is also constrained by the boundaries of the groups of entities gathering together the simulation semantic. The filled areas are then deformed to blend smoothly with the surroundings meshes

Geometry deformation for reducing cybersickness in VR

Virtual reality (VR) technologies became more and more widespread for a couple of years as they got more and more mature. The accessibility to VR highly increased thanks to recent low-cost commercial VR head mounted display systems and easy-to-use development toolkits. One important and well-studied human perception issue is related to motion sickness or cybersickness. In this paper we are dealing with case when users feel a visually induced induced self-motion that are not felt through their vestibular systems. This incoherent movement perception provokes cybersickness to the users. To tackle this issue, we present in this paper a novel method to reduce cybersickness through reducing visually induced self-motion by processing geometrically the virtual scene while navigating. The first prototype of geometry deformation applied on virtual building appearing in the peripheral vision of user has been implemented and experimented. The feedback from the experiment participants shows that the visually induced self-motion is reduced and the navigation quality and presence level are guaranteed

Multi-user interface for co-located real-time work with digital mock-up: a way to foster collaboration?

Nowadays more and more industrial design activities adopt the strategy of Concurrent Engineering (CE), which changes the way to carry out all the activities along the product’s lifecycle from sequential to parallel. Various experts of different activities produce technical data using domain-specific software. To augment the interoperability among the technical data, a Digital Mock-Up (DMU), or a Building Information Model (BIM) in architectural engineering can be used. Through an appropriate Computer–Human Interface (CHI), each expert has his/her own point-of-view (POV) of a specific representation of DMU’s technical data according to an involved domain. When multiple experts work collaboratively in the same place and at the same time, the number of CHIs is also multiplied by the number of experts. Instead of multiple CHIs, therefore, a unique CHI should be developed to support the multiview and multi-interaction collaborative works. Our contributions in this paper are (a) a concept of a CHI system with multi-view and multi-interaction of DMU for multiple users in collaborative design; (b) a state of the art of multi-view and multi-interaction metaphors; (c) an experiment to evaluate a collaborative application using multi-view CHI. The experimental results indicate that, in multi-view CHI working condition, users are more efficient than in the other two working conditions (multiple CHIs and split view CHI). Moreover, in multi-view CHI working condition, the user, who is helping the other, takes less mutual awareness of where the other collaborator works than the other two working conditions.Bourse de thèse de CSC (China Scholarship Council

Generation of subdivision surface from network of curves

Subdivision surfaces are usually used to construct freeform surfaces from network of curves for its ability and flexibility to deal with complex wireframes. In freeform surface designing, the designers usually draw at first some curves for describing the models conceived in their mind which form a curve network representing an object of arbitrary topology. Then 3D surfaces are computed to interpolate these curves in order to create a B-Rep model. If the subdivision surface is used in the workflow, its control polyhedrons generation from curves polygons could be a time-consuming stage. In this article, we develop an approach to generate automatically a control polyhedral mesh from an arbitrary topological curve network. One of common problems in interpolating surface patch using subdivision surfaces is how to determine the connectivity of control points. Arbitrary topological curve network has no restriction in topology structure, so another problem is that it has more ambiguousness in defining surface patches. There are three steps in our approach. Firstly, we compute a 1D mesh (a unique polygonal model) from curves. Secondly, we identify on the polygon different cycles that would be the boundaries of potential surface patches. Finally, in each identified cycle we apply an algorithm of quadrangulation to construct the control mesh of subdivision

Merging enriched Finite Element triangle meshes for fast prototyping of alternate solutions in the context of industrial maintenance

A new approach to the merging of Finite Element (FE) triangle meshes is proposed. Not only it takes into account the geometric aspects, but it also considers the way the semantic information possibly associated to the groups of entities (nodes, faces) can be maintained. Such high level modification capabilities are of major importance in all the engineering activities requiring fast modifications of meshes without going back to the CAD model. This is especially true in the context of industrial maintenance where the engineers often have to solve critical problems in very short time. Indeed, in this case, the product is already designed, the CAD models are not necessarily available and the FE models might be tuned. Thus, the product behaviour has to be studied and improved during its exploitation while prototyping directly several alternate solutions. Such a framework also finds interest in the preliminary design phases where alternative solutions have to be simulated. The algorithm first removes the intersecting faces in an n-ring neighbourhood so that the filling of the created holes produces triangles whose sizes smoothly evolve according to the possibly heterogeneous sizes of the surrounding triagles. The holefilling algorithm is driven by an aspect ratio factor which ensures that the produced triangulation fits well the FE requirements. It is also constrained by the boundaries of the groups of entities gathering together the simulation semantic. The filled areas are then deformed to blend smoothly with the surroundings meshes

Reducing Cybersickness by Geometry Deformation

One major and well-known issue that occurs during VR experience is the appearance of cybersickness, which refrains users from accepting VR technologies. The induced cybersickness is due to a self-motion feeling that is produced when users see objects moving in the virtual world. To reduce cybersickness several methods have been proposed in the literature, however they do not guarantee immersion and navigation quality. In this paper, a new method to reduce cybersickness is proposed. The geometric deformation of the virtual model displayed in the peripheral field of view allows reducing the self-motion perceived by the user. Pilot test results show that visually induced self-motion is reduced with a guaranteed immersion quality while the user navigation parameters are kept

Study of efficiency of multi view system in multi-disciplinary collaboration task

In this paper, we at first introduce the context of multi-disciplinary collaboration and the usage of multiple computer-human interfaces (chis) with domain specified software. Then we propose the co-located multi-view system with the technology of multi-representation, multi interaction and virtual reality. A study is investigated to evaluate the contribution to the proposed multi-view system in comparing with the traditional mono-view system during a multidisciplinary collaborative task. A multi-role collaborative application is developed to test the co-located collaboration with multiple representations in virtual reality environment. This collaborative application consists of a collaborative task which simulates industrial project review using multi-representation digital mock-up (dmu). The experiment is conducted with two persons under two different collaborative chi’s conditions: two mono-view systems and single multi-view system. The difference in term of verbal communication, contribution and efficiency of collaboration during the multidisciplinary collaborative task is analyzed to compare the two conditions

Filleting sharp edges of multi-partitioned volume finite element meshes

International audiencePurpose – The purpose of this paper is to set up a new framework to enable direct modifications of volume meshes enriched with semantic information associated to multiple partitions. An instance of filleting operator is prototyped under this framework and presented in the paper.Design/methodology/approach – In this paper, a generic mesh modification operator has been designed and a new instance of this operator for filleting finite element (FE) sharp edges of tetrahedral multi-partitioned meshes is also pro-posed. The filleting operator works in two main steps. The outer skin of the tetrahedral mesh is first deformed to round user-specified sharp edges while satisfying constraints relative to the shape of the so-called Virtual Group Boundaries. Then, in the filleting area, the positions of the inner nodes are relaxed to improve the aspect ratio of the mesh elements.Findings – The classical mainstream methodology for product behaviour optimization involves the repetition of four steps: CAD modelling, meshing of CAD models, enrichment of models with FE simulation semantics and FEA. This paper highlights how this methodology could be simplified by two steps: simulation model modification and FEA. The authors set up a new framework to enable direct modifications of volume meshes enriched with semantic information associated to multiple and the corresponding fillet operator is devised.Research limitations/implications – The proposed framework shows only a paradigm of direct modifications of semantic enriched meshes. It could be further more improved by adding or changing the modules inside. The fillet operator does not take into account the exact radius imposed by user.With this proposed fillet operator the mesh element density may not be enough high to obtain wished smoothness.Originality/value – This paper fulfils an identified industry need to speed up the product behaviour analysis process by directly modifying the simulation semantic enriched meshes

A Multi-view and Multi-interaction System for Digital-mock up’s collaborative environment

The current industrial PLM tool generally relies on Concurrent Engineering (CE), which involves conducting product design and manufacturing stages in parallel and integrating technical data for sharing among different experts in parallel. Various experts use domain-specific software to produce various data. This package of data is usually called Digital mock-up (DMU), as well as Building Information Model (BIM) in architectural engineering. For sharing the DMU data, many works have been done to improve the interoperability among the engineering software and among the models in domains of mechanical design and eco-design. However, the computer-human interaction (CHI) currently used in the context of CE project reviews is not optimized to enhance the interoperability among various experts of different domains. Here the CHI concerns both complex DMU visualization and multi-users interaction. Since the DMU has its multiple representations according to involved domains, therefore when various experts need to work together on the DMU they may prefer their own point-of-view on the DMU and proper manner to interact with the DMU.With the development of 3D visualization and virtual reality CHI technology, it is possible to devise more intuitive tools and methods to enhance the interoperability of collaboration among experts both in multi-view and multi-interaction for co-located synchronous collaborative design activities. In this paper, we discuss the different approaches of displaying multiple point-of-views of DMU and multiple interactions with DMU in the context of 3D visualization, virtual reality and augmented reality. A co-located collaborative environment of CHI supporting system is proposed. This collaborative environment allows the experts to see respectively the multiple point-of-view of the DMU in front of a unique display system and to interact with the DMU in using different metaphors according to their specific needs. This could be used to assist collaborative design during project review where some decision on product design solution should be made.CSC (China Scholarship Council