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Now showing 1 - 10 of 23
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    A Virtual Collaborative Learning Environment
    (The Eurographics Association, 2022) Ficheman, Irene Karaguilla; Lopes, Roseli de Deus; Krüger, Susana Ester; Xavier Pueyo; Manuel Próspero dos Santos; Luiz Velho
    This paper presents a virtual learning environment developed for music education and includes both individual and collaborative interactive environments. This learning environment is a music composition edutainment software, which is being developed in collaboration between the University of São Paulo, Laboratório de Sistemas Integráveis (LSI) da Escola Politécnica da Universidade de São Paulo (USP) and the São Paulo State Orchestra, Coordenadoria de Programas Educacionais da Orquestra Sinfónica do Estado de São Paulo (OSESP). Recent research in music education as well as new computer and telecommunication technologies are being applied in arder to offer creative virtual learning environments to the students and offer pedagogical toais to the teachers.
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    Hoops Fusion: Synthesis of View-dependent Convex Occluders from a Set of Objects
    (The Eurographics Association, 2022) Ríos, Àlex; Navazo, Isabel; Xavier Pueyo; Manuel Próspero dos Santos; Luiz Velho
    Visibility determination is a requirement to navigate through complex scenes. Occluder fusion algorithms generate convex occluders that are contained in the umbra cast by a group of objects given an area light. Hoops are non-convex, but view-dependent convex, non-planar closed polylines that can be used to compute occlusion for objects that not necessarily have large interior convex sets. ln this paper we present an efficient, robust, and incremental octree-based algorithm to synthesize hoops for a set of objects and to compute the hoopís umbra. Experimental results demonstrate the techniqueís effectiveness to compute occluder fusion of non-convex objects.
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    MIXDesign, Tangible Mixed Reality for Architectural Design
    (The Eurographics Association, 2022) Salles Dias, J. Miguel; Santos, Pedro; Bastos, Rafael; Monteiro, Luis; Silvestre, Rui; Diniz, Nancy; Xavier Pueyo; Manuel Próspero dos Santos; Luiz Velho
    MIXDesign, provides a tangible Mixed-Reality system oriented towards tasks in Architectural Design, in severa! usage scenarios, such as Conceptual Design, Client Brief or even Architectural Design education. With MIXDesign, an architect can intuitively interact with a real scale model of the design, in normal working settings, where he can observe an enhanced version of the scale model, with JD virtual objects registered to the real ones. The architect is then able to use intuitive tangible interfaces, such as a paddle, to choose menu options, select a JD virtual object, transport a virtual object within the scale model surroundings and geometrically transform an object (by rotation or scaling). MIXDesign provides a platform for testing new design concepts while seamlessly transporting the Architect from Reality (RE) to Augmented Reality (AR) and then through Augmented Virtuality (AV), towards afull Virtual Environment (VE), and back, where he can perceive andjudge both the virtual and the real models, interactively and in real-time.
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    INTERCOMUNICANDO - Computer Assisted Communication for Severely Handicapped Persons
    (The Eurographics Association, 2022) Lopes, João Brisson; Amaro, Ricardo; Pereira, António; Xavier Pueyo; Manuel Próspero dos Santos; Luiz Velho
    This paper presents project INTERCOMUNICANDO whose aim is to provide computer assisted pictogram based communication as a rehabilitation toolfor severely handicapped persons. The project developed a suite of integrated applications that use autonomous agents with speech and animation to provide on-line help, feedback and motivation to users. The paper addresses user interface design. It also addresses the user requirements and the development methodology used to provide users with ali services, including input, that smoothly adapt to the kind and degree of disability of each user. The current state of the project is described along with results. Conclusions and recommendations for the following project (RECRIA) are presented.
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    Powering Multiprojection lmmersive Environments with Clusters of Commodity Computers
    (The Eurographics Association, 2022) Soares, Luciano Pereira; Cabral, Márcio Calixto; Bressan, Paulo Alexandre; Lopes, Roseli de Deus; Zuffo, Marcelo Knörich; Xavier Pueyo; Manuel Próspero dos Santos; Luiz Velho
    Multiprojection lmmersive Environments are used in many fields such as science, engineering and art. Virtual Reality (VR) oriented systems have been powered traditionally by high-end graphics workstations or supercomputers but recently, clusters of commodity computers (PCs, Macintoshes, low cost workstations) have become a practical alternative. The advantages of a commodity cluster include low cost, flexibility, access to technology, and performance scalability. ln this paper we describe the family of graphics clusters developed to power Multiprojection lmmersive Environments. Design issues and results are presented considering the CAVERNA DigitalTM, the first five-sided cubic Multiprojection lmmersive Environment implemented in South America.
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    A Density Estimation Technique for Radiosity
    (The Eurographics Association, 2022) Lastra, Miguel; Urefía, Carlos; Revelles, Jorge; Montes, Rosana; Xavier Pueyo; Manuel Próspero dos Santos; Luiz Velho
    Radiosity computation on scenes including objects with a complex geometry, or with a large number of faces and meshes with very different sizes, is very complex. We presenta new method (based on the Photon Maps method [7]) where density estimation on the tangent plane at each surface point is performed for irradiance computation by using photon paths (fine segments traveled by a ray) instead of photon impacts. Therefore we improve the results for scenes containing small objects which receive only afew impacts. Also, geometry is completely decoupledfrom radiosity computation.
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    A Constraint Manager to Support Virtual Maintainability
    (The Eurographics Association, 2022) Marcelino, Luis; Murray, Norman; Fernando, Terrence; Xavier Pueyo; Manuel Próspero dos Santos; Luiz Velho
    Virtual prototyping tools have already captivated the industry's interest as a viable design tool. One of the key challenges for the research community is to extend the capabilities of Virtual Reality technology beyond its current scope of ergonomics and design reviews. The research presented in this paper is part of a larger research programme that aims to perform maintainability assessment on virtual prototypes. This paper discusses the design and implementation of a geometric constraint manager that has been designed to support physical realism and interactive assembly and disassembly tasks within virtual environments. The key techniques employed by the constraint manager are direct interaction, automatic constraint recognition, constraint satisfaction and constrained motion. Various optimisation techniques have been implemented to achieve real-time interaction with large industrial models.
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    Algorithms for Point-Polygon Collision Oetection in 20
    (The Eurographics Association, 2022) Delgado, Juan J. Jiménez; Sánchez, Rafael J. Segura; Higueruela, Francisco R. Feito; Xavier Pueyo; Manuel Próspero dos Santos; Luiz Velho
    ln this article, several algorithms for the collision detection between a point and a polygon on a plane are presented. Coverings by triangles and barycentric coordinates are used. Temporal and geometric coherence are usedfor reducing their performance times. A study of times has been carried out; it shows that these simple and robust algorithms are efficient. Also, these algorithms can be used for non convex figures and they have the advantage of being easily extended to JD.
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    Direct Modelíng: from Sketches to 3D Models
    (The Eurographics Association, 2022) Naya, Fernando; Jorge, Joaquim A.; Conesa, Julián; Contera, Manuel; Gomis, José Maria; Xavier Pueyo; Manuel Próspero dos Santos; Luiz Velho
    ln spite of recent advances in Computer Aided Design, Graphical User Interfaces (GUJ) are, by and large, still at the stage of the so-called WIMP (Window, Icon, Menu, Pointing device) approach. ln recent years, our research team has developed different algorithms in Geometric Reconstruction. The aim of this effort is to obtain an automatic (or, at least, easy-to-use) means to generate 3D models from freehand 2D drawings. This approach serves as the basis to a calligraphic interface, based onfreehand sketches and gestures, described as a prototype application capable of modeling special kinds of objects such as normalon and quasi-normalon polyhedra. Using our system users can directly draw the axonometric view of an object to yield a 3D model. White much work remains to be done, the current application already shows gains with respect to more traditional forms ofmodeling in that it embodies a drawing approachfamiliar to most draflspeople, who can start modeling relatively complex shapes without much training. Preliminary studies show that our modeling system compares favorably to commercial grade CAD systems both in number of operations required to creating objects and time to accomplish simple modeling tasks.
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    Visualization Techniques in a Building Potential Simulator Using Sunlíght Access Con
    (The Eurographics Association, 2022) Grazziotin, Pablo Colossi; Freitas, Carla M. Dai Sasso; Turkienicz, Benamy; Pereira, Fernando O. Ruttkay; Xavier Pueyo; Manuel Próspero dos Santos; Luiz Velho
    This paper presents the use of a technique known as solar envelope in the simulation of building potential of urban plots as well as the improvement of 2D and 3D visualization techniques of simulation results. The consideration of sunlight access in urban planning fulfills basic requirements for improving the quality of buildings regarding thermal comfort. The work has improved an existing decision support system, CityZoom, which provides an environment where severa[ performance models çan be used in an integrated way for urban planning. One of these models is BlockMagic, where insolation can be simulated along with Master Plans rules, seeking to maximize both building potential and sunlight access. Resides the adoption of the solar envelope concept in the simulation, 2D and 3D visualization techniques were developed in order to show sun-path diagram, sky vault obstruction due to neighboring buildings, and 3D view with shadows obtained from the buildings simulation.