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 Subject "3D interaction"

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    A volumetric virtual environment for catheter insertion simulation
    (2000-06) Zorcolo, Antonio; Gobbetti, Enrico; Zanetti, Gianluigi; Tuveri, Massimiliano
    We present an experimental catheter insertion simulation system that provides users co-registered haptic and head-tracked stereoscopic visual feedback. The system works on patient-specific volumetric data acquired using standard medical imaging modalities. The actual needle insertion operation is simulated for individual patients, rather than being an example of a model surgical procedure on standard anatomy. Patient specific features may thus be studied in detail by the trainees, overcoming one of the major limitations of current training techniques.
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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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    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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    Catheter insertion simulation with co-registered direct volume rendering and haptic feedback
    (IOS, 2000-01) Gobbetti, Enrico; Tuveri, Massimiliano; Zanetti, Gianluigi; Zorcolo, Antonio
    We have developed an experimental catheter insertion simulation system supporting head-tracked stereoscopic viewing of volumetric anatomic reconstructions registered with direct haptic 3D interaction. The system takes as input data acquired with standard medical imaging modalities and regards it as a visual and haptic environment whose parameters are interactively defined using look-up tables. The system's display, positioned like a surgical table, provide a realistic impression of looking down at the patient. Measuring head motion via a six degrees-of-freedom head tracker, good positions to observe the anatomy and identify the catheter insertion point are quickly established with simple head motion. By generating appropriate stereoscopic images and co-registering physical and virtual spaces beforehand, volumes appear at fixed physical positions and it is possible to control catheter insertion via direct interaction with a PHANToM haptic device. During the insertion procedure, the system provides perception of the effort of penetration and deviation inside the traversed tissues. Semi-transparent volumetric rendering augment the sensory feedback with the visual indication of the inserted catheter position inside the body.
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    FOX: The Focus Sliding Surface Metaphor for Natural Exploration of Massive Models on Large-scale Light Field Displays
    (ACM, 2011-12) Marton, Fabio; Agus, Marco; Pintore, Giovanni; Gobbetti, Enrico
    We report on a virtual environment for natural immersive exploration of extremely detailed surface models on light field displays. Our specialized 3D user interface allows casual users to inspect 3D objects at various scales, integrating panning, rotating, and zooming controls into a single low-degree-of-freedom operation, while taking into account the requirements for comfortable viewing on a light field display hardware. Specialized multiresolution structures, embedding a fine-grained per-patch spatial index within a coarse-grained patch-based mesh structure, are exploited for fast batched I/O, GPU accelerated rendering, and user-interaction-system-related geometric queries. The capabilities of the system are demonstrated by the interactive inspection of a giga-triangle dataset on a large scale 35MPixel light field display controlled by wired or vision-based devices.
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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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    Object-oriented design of dynamic graphics applications
    (Wiley, 1992) Gobbetti, Enrico; Turner, Russell
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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.