Search Results

Now showing 1 - 10 of 21
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    Haptic Simulation, Perception and Manipulation of Deformable Objects
    (The Eurographics Association, 2007) Magnenat-Thalmann, Nadia; Volino, Pascal; Bonanni, Ugo; Summers, Ian R.; Brady, A. C.; Qu, J.; Allerkamp, D.; Fontana, M.; Tarri, F.; Salsedo, F.; Bergamasco, Massimo; Karol Myszkowski and Vlastimil Havran
    This tutorial addresses haptic simulation, perception and manipulation of complex deformable objects in virtual environments (VE). We first introduce HAPTEX, a research project dealing with haptic simulation and perception of textiles in VEs. Then, we present state-of-the-art techniques concerning haptic simulation and rendering, ranging from physically based modelling to control issues of tactile arrays and force-feedback devices. In the section on cloth simulation for haptic systems we describe techniques for simulating textiles adapted to the specific context of haptic applications. The section concerning tactile aspects of virtual objects shows how arrays of contactors on the skin can be used to provide appropriate spatiotemporal patterns of mechanical excitation to the underlying mechanoreceptors. Finally, the last section addresses the problem of developing suitable force feedback technologies for the realistic haptic rendering of the physical interaction with deformable objects, addressing the design of novel force feedback systems, innovative concepts for curvature simulation and control algorithms for accuracy improvement.
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    Avatar Markup Language
    (The Eurographics Association, 2002) Kshirsagar, Sumedha; Magnenat-Thalmann, Nadia; Guye-Vuillème, Anthony; Thalmann, Daniel; Kamyab, Kaveh; Mamdani, Ebrahim; S. Mueller and W. Stuerzlinger
    Synchronization of speech, facial expressions and body gestures is one of the most critical problems in realistic avatar animation in virtual environments. In this paper, we address this problem by proposing a new high-level animation language to describe avatar animation. The Avatar Markup Language (AML), based on XML, encapsulates the Text to Speech, Facial Animation and Body Animation in a unified manner with appropriate synchronization. We use low-level animation parameters, defined by the MPEG-4 standard, to demonstrate the use of the AML. However, the AML itself is independent of any low-level parameters as such. AML can be effectively used by intelligent software agents to control their 3D graphical representations in the virtual environments. With the help of the associated tools, AML also facilitates to create and share 3D avatar animations quickly and easily. We also discuss how the language has been developed and used within the SoNG project framework. The tools developed to use AML in a real-time animation system incorporating intelligent agents and 3D avatars are also discussed subsequently.
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    Real-time Inhabited Virtual Worlds and Interaction - interactive virtual worlds module
    (The Eurographics Association, 2006) Magnenat-Thalmann, Nadia; Papagiannakis, George; Egges, Arjan; Lyard, Etienne; Nadia Magnenat-Thalmann and Katja Bühler
    Virtual Worlds [MK94] and their concept of cyber-real space interplay invoke such interactive digital narratives that promote new patterns of understanding. However, the "narrative" and "interactive" part, which refers to a set of events happening during a certain period of time and providing aesthetic, dramaturgical and emotional elements, objects and attitudes ([NM00], [TYK01]) is still an early topic of research. Mixing such aesthetic ambiences with interactive virtual character augmentations [CMM*03] and adding dramatic tension has developed very recently these narrative patterns into an exciting new edutainment medium [LHM03]. With the interplay of a modern real-time framework for integrated interactive virtual character simulation, we can enhance the experience with full virtual character simulations.
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    Visualization of woven cloth
    (The Eurographics Association, 2003) Adabala, Neeharika; Magnenat-Thalmann, Nadia; Fei, Guangzheng; Philip Dutre and Frank Suykens and Per H. Christensen and Daniel Cohen-Or
    A technique for visualizing clothes is proposed that can handle rendering of complex weave patterns. An industrial standard of weave representation is used to derive the weave pattern and a detailed model of light interaction with the pattern is developed. The proposed visualization technique supports viewing of cloth at various levels of detail, and provides a solution for rendering both back and front surfaces of cloth. The technique works for a wide variation in colors of threads, ranging from a single color for both warps and wefts to several colors of threads, woven into a single fabric. The inhomogeneous nature of transparency of woven materials is also captured. To date no technique for visualizing woven clothes has addressed the problem of visualizing complex weave patterns and therefore the above mentioned features are difficult and often impossible to capture with existing techniques. The capabilities of the proposed approach are demonstrated with rendered examples.
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    Course: Modeling Individualities in Groups and Crowds
    (The Eurographics Association, 2009) Donikian, Stéphane; Magnenat-Thalmann, Nadia; Pettré, Julien; Thalmann, Daniel; K. Museth and D. Weiskopf
    Crowds are part of our everyday life experience and essential when working with realistic interactive environments. Domains of application for such simulations range from populating artificial cities to entertainment, and virtual reality exposure therapy for crowd phobia. We mainly focus on real-time applications where the visual uniqueness of the characters composing a crowd is paramount. On the one hand, it is required to display several thousands of virtual humans at high frame rates. On the other hand, each character has to be different from all others, and its visual quality highly detailed. Variety in rendering is defined as having different forms or types and is necessary to create believable and reliable crowds in opposition to uniform crowds. For a human crowd, variation can come from the following aspects: gender, age, morphology, head, kind of clothes, color of clothes and behaviors.
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    Visyllable Based Speech Animation
    (Blackwell Publishers, Inc and the Eurographics Association, 2003) Kshirsagar, Sumedha; Magnenat-Thalmann, Nadia
    Visemes are visual counterpart of phonemes. Traditionally, the speech animation of 3D synthetic faces involvesextraction of visemes from input speech followed by the application of co-articulation rules to generate realisticanimation. In this paper, we take a novel approach for speech animation - using visyllables, the visual counterpartof syllables. The approach results into a concatenative visyllable based speech animation system. The key contributionof this paper lies in two main areas. Firstly, we define a set of visyllable units for spoken English along withthe associated phonological rules for valid syllables. Based on these rules, we have implemented a syllabificationalgorithm that allows segmentation of a given phoneme stream into syllables and subsequently visyllables. Secondly,we have recorded the database of visyllables using a facial motion capture system. The recorded visyllableunits are post-processed semi-automatically to ensure continuity at the vowel boundaries of the visyllables. We defineeach visyllable in terms of the Facial Movement Parameters (FMP). The FMPs are obtained as a result of thestatistical analysis of the facial motion capture data. The FMPs allow a compact representation of the visyllables.Further, the FMPs also facilitate the formulation of rules for boundary matching and smoothing after concatenatingthe visyllables units. Ours is the first visyllable based speech animation system. The proposed technique iseasy to implement, effective for real-time as well as non real-time applications and results into realistic speechanimation.Categories and Subject Descriptors (according to ACM CCS): 1.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism
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    Facial Modeling and Animation
    (Eurographics Association, 2003) Haber, Jörg; Terzopoulos, Demetri; Magnenat-Thalmann, Nadia; Blanz, Volker
    In this tutorial we present an overview of the concepts and current techniques that have been developed to model and animate human faces. We introduce the research area of facial modeling and animation by its history and applications. As a necessary prerequisite for facial modeling, data acquisition is discussed in detail. We describe basic concepts of facial animation and present different approaches including parametric models, performance-, physics-, and image-based methods. State-of-the-art techniques such as MPEG-4 facial animation parameters, mass-spring networks for skin models, and face space representations are part of these approaches. We furthermore discuss texturing of head models and rendering of skin and hair, addressing problems related to texture synthesis, bump mapping with graphics hardware, and dynamics of hair. Typical applications for facial modeling and animation such as speech synchronization, head morphing, and forensic applications are presented and explained.
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    Key Techniques for interactive Virtual Garment Simulation
    (The Eurographics Association, 2005) Volino, Pascal; Magnenat-Thalmann, Nadia; Thomaszewski, Bernhard; Wacker, Markus; Ming Lin and Celine Loscos
    Virtual garment design and simulation involves a combination of a large range of techniques, involving mechanical simulation, collision detection, and user interface techniques for creating garments. Here, we perform an extensive review of the evolution of these techniques made in the last decade to bring virtual garments to the reach of computer applications not only aimed at graphics, but also at CAD techniques for the garment industry.
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    Virtual Hip Joint: from Computer Graphics to Computer-Assisted Diagnosis
    (The Eurographics Association, 2009) Charbonnier, Caecilia; Schmid, Jérôme; Kolo-Christophe, Frank; Magnenat-Thalmann, Nadia; Becker, Christoph; Hoffmeyer, Pierre; K. Bühler and D. Bartz
    Osteoarthritis (OA) is a major musculoskeletal disorder which causes are not always fully understood. Femoroacetabular impingements such as cam/ pincer cannot always explain observed OA in hips with normal morphology. This paper investigates the hypothesis of extreme repetitive movements as a source of cartilage degeneration. We present a clinical study conducted with professional ballet dancers and a methodology to perform functional simulations of the hip joint in extreme postures. Throughout the process, various computer graphics techniques are used, like motion capture, 3D body scanning and physically-based models. In addition to accelerate and strengthen some tasks, these techniques strongly participate in the clinical understanding of OA related to motion. Preliminary results have indeed shown a significant correlation between the location of impingements and radiologically observed damage zones in the labrum cartilage.
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    Towards the Virtual Physiological Human
    (The Eurographics Association, 2007) Magnenat-Thalmann, Nadia; Gilles, Benjamin; Delingette, Hervé; Giachetti, Andrea; Agus, Marco; Karol Myszkowski and Vlastimil Havran
    The objective of this tutorial is to train students and researchers in the various domains involving the modelling and simulation of the human body for medical purposes. Human body representations have been used for centuries to help in understanding and documenting the shape and function of its compounding parts. Nowadays, medical acquisition devices especially medical scanners are able to produce a large amount of information, such as highresolution volumes, temporal sequences or functional images, more-and-more difficult to analyse and visualise. In other words, we measure much more than we understand. In this context, higher-level information such as anatomical and functional models is increasingly required to support diagnosis and treatment. Three levels of complexity can be distinguished (geometry, function and control) where modelling and simulation methods take place. In this tutorial, we will present the current research issues towards the patient-specific reconstruction of virtual models and their functional simulation. We will focus on the computer graphics aspects involved in medical modelling/ simulation: deformable model-based segmentation, mesh optimisation, data fusion, interactive mechanical simulation, cost-efficient visualisation, etc. Examples will be given in the musculoskeletal, cardiac and neurological domains. All speakers are partners of the EU project "3D Anatomical Human" led by MIRALab - University of Geneva.