CRS4 Libro, Contributo in un libro

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https://hdl.handle.net/11050/56

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Mostra il contenuto di CRS4 Libro, Contributo in un libro per Autore "Balaguer, Jean-Francis"

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    An Integrated Environment to Visually Construct 3D Animations
    (ACM, 1995) Gobbetti, Enrico; Balaguer, Jean-Francis
    In this paper, we present an expressive 3D animation environment that enables users to rapidly and visually prototype animated worlds with a fully 3D user-interface. A 3D device allows the specification of complex 3D motion, while virtual tools are visible mediators that live in the same 3D space as application objects and supply the interaction metaphors to control them. In our environment, there is no intrinsic difference between user-interface and application objects. Multi-way constraints provide the necessary tight-coupling among components that makes it possible to seamlessly compose interactive and animated behaviors. By recording the effects of manipulations, all the expressive power of the 3D user-interface is exploited to define animations. Effective editing of recorded manipulations is made possible by compacting all continuous parameter evolutions with an incremental data-reduction algorithm, designed to preserve both geometry and timing. The automatic generation of editable representations of interactive performances overcomes one of the major limitations of current performance animation systems. Novel interactive solutions to animation problems are made possible by the tight integration of all system components. In particular, animations can be synchronized by using constrained manipulation during playback. The accompanying video tape illustrates our approach with interactive sequences showing the visual construction of 3D animated worlds. All the demonstrations were recorded live and were not edited.
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    An Object-oriented Methodology with Dynamic Variables for Animation and Scientific Visualization
    (Springer, 1990) Turner, Russell; Gobbetti, Enrico; Balaguer, Jean-Francis; Mangili, Angelo; Thalmann, Daniel
    An object-oriented design is presented for building dynamic three-dimensional applications. This design takes the form of the Fifth Dimension Toolkit consisting of a set of interrelated classes whose instances may be connected together in a variety of ways to form different applications. Animation is obtained by connecting graphical objects to dynamic variables, which are able to change their values over time by responding to events. The Fifth Dimension Toolkit is the core of the Fifth Dimension Project, a research project for animating synthetic actors in their environment. The design philosophy and methodology of the toolkit are also described, as well as some of the implementation issues for the Silicon Graphics Iris 4D workstation.
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    Building an interactive 3D animation system
    (Prentice Hall, 1993) Gobbetti, Enrico; Balaguer, Jean-Francis; Mangili, Angelo; Turner, Russell
    The continued improvement and proliferation of graphics hardware for workstations and personal computers has brought increasing prominence to a newer style of software application program. This style relies on fast, high quality graphics displays coupled with expressive input devices to achieve real-time animation and direct-manipulation interaction metaphors. Such applications impose a rather different conceptual approach, on both the user and the programmer, than more traditional software. The application program can be thought of increasingly as a virtual machine, with a tangible two or three dimensional appearance, behavior and tactile response. Dynamic graphics techniques are now considered essential for making computers easier to use, and interactive and graphical interfaces that allow the presentation and the direct manipulation of information in a pictorial form is now an important part of most of modern graphics software tools
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    i3D: a high-speed 3D Web browser
    (ACM, 1995) Balaguer, Jean-Francis; Gobbetti, Enrico
    In this paper, we present i3D, a system that combines the 3D input and high-performance rendering capabilities of high-end virtual reality systems with the data fetching abilities of network browsers. Using a Spaceball, the user can intuitively navigate inside the three-dimensional data, while selecting 3D objects with the mouse triggers requests for access to remote media documents that can be text, still images, animations or even other 3D models. Time-critical rendering techniques allow the system to display complex 3D scenes at high and constant frame rates, making it possible to use it in the context of large scale projects. The system is currently being used at CERN as a visualization and data management tool for the design of the new Large Hadron Collider, and at CRS4 for the Virtual Sardinia project and in the networked educational system IPERLER. i3D is available through anonymous ftp from various sites on the Internet.
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    i3D: an interactive system for exploring annotated 3D environments
    (World Scientific, 1995-08) Gobbetti, Enrico; Balaguer, Jean-Francis
    In this paper, we present I3D, a system that combines the 3D input and high-performance rendering capabilities of high-end virtual reality systems with the data fetching abilities of network browsers. Using a Spaceball, the user can intuitively navigate inside the three-dimensional data, while selecting 3D objects with the mouse triggers requests for access to remote media documents that can be text, still images, animations or even other 3D models. Time-critical rendering techniques allow the system to display complex 3D scenes at high and constant frame rates, making it possible to use it in the context of large scale projects. The system is currently being used at CERN as a visualization and data management tool for the design of the new Large Hadron Collider, and will be used at CRS4 in the networked educational system IPERLER.
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    Interactive Scene Walkthrough Using a Physically-Based Virtual Camera
    (Vieweg, 1991) Turner, Russell; Balaguer, Jean-Francis; Gobbetti, Enrico; Thalmann, Daniel
    One of the most powerful results of recent advances in graphics hardware is the ability of a computer user to interactively explore a virtual buildin gor landscape. The newest three-dimensional input devices, together with high speed {3D} graphics workstations, make it possible to view and move through a {3D} scene by interactively controlling the motion of a virtual camera. In this paper, we describe how natural and intuitive control of building walkthrough can be achieved by using a physically-based model of the virtual camera's behavior. Using the laws of classical mechanics to create and abstract physical model of the camera, we then simulate the virtual camera motion in real time in response to force date from the various {3D} input devices (e.g. the Spaceball and Polhemus 3Space Digitizer). The resulting interactive behavior of the model is determined by several physical parameters such as mass, moment of inertia, and various friction coefficients which can all be varied interactively, and by constraints on the camera's degrees of freedom. This allows us to explore a continuous range of physically-based metaphors for controlling the camera motion. We present the results of experiments using several of these metaphors for virtual camera motion and describe the effects of the various physical parameters.
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    Physically-based interactive camera motion control using 3D input devices
    (Springer, 1991) Turner, Russell; Balaguer, Jean-Francis; Gobbetti, Enrico; Thalmann, Daniel
    The newest three-dimensional input devices, together with high speed graphics workstations, make it possible to interactively specify virtual camera motions for animation in real time. In this paper, we describe how naturalistic interaction and realistic-looking motion can be achieved by using a physically-based model of the camera's behavior. Our approach is to create an abstract physical model of the camera, using the laws of classical mechanics, which is used to simulate the virtual camera motion in real time in response to force data from the various 3D input devices (e.g. the Spaceball, Polhemus and DataGlove). The behavior of the model is determined by several physical parameters such as mass, moment of inertia, and various friction coefficients which can all be varied interactively, and by constraints on the camera's degrees of freedom which can be simulated by setting certain friction parameters to very high values. This allows us to explore a continuous range of physically-based metaphors for controlling the camera motion. We present the results of experiments with several of these metaphors and contrast them with existing ones.
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    Supporting interactive animation using multi-way constraints
    (Springer, 1995) Balaguer, Jean-Francis; Gobbetti, Enrico
    This paper presents how the animation subsystem of an interactive environment for the visual construction of 3D animations has been modeled on top of an object-oriented constraint imperative architecture. In our architecture, there is no intrinsic difference between user-interface and application objects. Multi-way dataflow constraints provide the necessary tight coupling among components that makes it possible to seamlessly compose animated and interactive behaviors. Indirect paths allow an effective use of the constraint model in the context of dynamic applications. The ability of the underlying constraint solver to deal with hierarchies of multi-way, multi-output dataflow constraints, together with the ability of the central state manager to handle indirect constraints are exploited to define most of the behaviors of the modeling and animation components in a declarative way. The ease of integration between all system's components opens the door to novel interactive solution to modeling and animation problems. By recording the effects of the user's manipulations on the models, all the expressive power of the 3D user interface is exploited when defining animations. This performance-based approach complements standard key-framing systems by providing the ability to create animations with straight-ahead actions. At the end of the recording session, animation tracks are automatically updated to integrate the new piece of animation. Animation components can be easily synchronized using constrained manipulation during playback. The system demonstrates that, although they are limited to expressing acyclic conflict-free graphs, multi-way dataflow constraint are general enough to model a large variety of behaviors while remaining efficient enough to ensure the responsiveness of large interactive 3D graphics applications.
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    VB2: an architecture for interaction in synthetic worlds
    (ACM, 1993) Gobbetti, Enrico; Balaguer, Jean-Francis
    This paper describes the VB2 architecture for the construction of three-dimensional interactive applications. The system's state and behavior are uniformly represented as a network of interrelated objects. Dynamic components are modeled by active variables, while multi-way relations are modeled by hierarchical constraints. Daemons are used to sequence between system states in reaction to changes in variable values. The constraint network is efficiently maintained by an incremental constraint solver based on an enhancement of SkyBlue. Multiple devices are used to interact with the synthetic world through the use of various interaction paradigms, including immersive environments with visual and audio feedback. Interaction techniques range from direct manipulation, to gestural input and three-dimensional virtual tools. Adaptive pattern recognition is used to increase input device expressiveness by enhancing sensor data with classification information. Virtual tools, which are encapsulations of visual appearance and behavior, present a selective view of manipulated models' information and offer an interaction metaphor to control it. Since virtual tools are first class objects, they can be assembled into more complex tools, much in the same way that simple tools are built on top of a modeling hierarchy. The architecture is currently being used to build a virtual reality animation system.
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    Virtuality Builder II: on the topic of 3D interaction
    (1993) Gobbetti, Enrico; Balaguer, Jean-Francis
    Most of today's user interfaces for 3D graphics systems still predominantly use 2D widgets, even though current graphical hardware should make it possible to create applications in which the user directly manipulates aspects of three-dimensional synthetic worlds. The difficulties associated with achieving the key goal of immersion has led the research in virtual environments to concentrate far more on the development of new input and display devices than on higher-level techniques for 3D interaction. It is only recently that interaction with synthetic worlds has tried to go beyond straightforward interpretation of physical device data. The design space for 3D interaction tools and techniques remains mostly unexplored, while being far larger than in standard 2D applications. Moreover, as stated by Myers, "the only reliable way to generate quality interfaces is to test prototypes with users and modify the design based on their comments". The creation of complex interactive applications is an inherently iterative process that requires user interface tools, such as toolkits or frameworks. The lack of experience in 3D interfaces makes it extremely difficult to design 3D interface toolkits or frameworks. We believe that offering the possibility to rapidly prototype and test novel interaction techniques should be the primary goal of such tools. It is therefore more important for these tools to provide a wide range of interaction components, than to enforce a particular interface style. In this paper we present the Virtuality Builder II (VB2) framework developed at the Swiss Federal Institute of Technology for the construction of 3D interactive applications. First, we'll give an overview of the design concepts of VB2. Next, we'll concentrate on how users interact with dynamic models through direct manipulation, gestures, and virtual tools.