Alvar Vinacua - Profile on Academia.edu (original) (raw)
Papers by Alvar Vinacua
The NSF Invitational Workshop on Distributed Information, Computation, and Process Management for... more The NSF Invitational Workshop on Distributed Information, Computation, and Process Management for Scientific and Engineering Environments (DICPM) brought together domain specialists from engineering and the ocean, atmospheric, and space sciences involved in the development and use of simulations of complex systems, and computer scientists working on distributed repositories, visualization, and resource management. The objective was to formulate directions for research efforts to facilitate effective collaboration and to help increase access to information and sharing of results and tools useful in large-scale, distributed, multidisciplinary scientific and engineering environments. Three broad problem areas inhibit such activities: (1) Computational, e.g, insufficient infrastructure for the sharing of very large amounts of information, results, and tools; (2) Structural institutional barriers, e.g., funding, publication, and promotion policies; and (3) Social, e.g., communication barriers stemming from narrow specialization. The participants supported specific steps to address these problems: explicit support and incentives for multidisciplinary activities; the development of digitial libraries to enhance interdisciplinary communication and understanding; and development of a "virtual scientific marketplace" to disseminate tools, results, and expertise;
Example-guided segmentation
Modern adquisition techniques provide 3D datasets with unprecedented detail. Both triangle-based ... more Modern adquisition techniques provide 3D datasets with unprecedented detail. Both triangle-based and point-based techniques have been proposed for efficient rendering of these objects. We present a new technique for interactive visualization of volumetric data which combines polygonal faces for flat areas and oriented points for curved regions. The paper focuses on extracting large polygonal faces from voxel data. The key ingredient is a region-growing algorithm which maintains a discrete representation of the set of planes that satisfy a separability problem. A robust representation of this set of planes based on a discretized 4D convex polytope is also discussed. The proposed face extraction algorithm is able to recover information at sub-voxel precision and automatically detects sharp edges.
A Construction for VC1 Continuity of Rational Bézier Patches
Mathematical Methods in Computer Aided Geometric Design, 1989
Modeling Closed Surfaces: A Comparison of Existing Methods
Mathematical Methods in Computer Aided Geometric Design II, 1992
The cage-based deformation of a 3D object through generalized barycentric coordinates is a simple... more The cage-based deformation of a 3D object through generalized barycentric coordinates is a simple, ecient, eective and hence widely used shape manipulation scheme. Editing vertices of the polyhedral cage induces a smooth space deformation of its interior; the vertices thus become control handles of thenal deformation. However, in some application elds, as medicine, constrained volumepreserving deformations are required.
Surface fairing for ship hull design application
Mathematical Engineering in Industry
... reference to library · Related research. The Automated Fairing of Ship Hull Lines Using Forma... more ... reference to library · Related research. The Automated Fairing of Ship Hull Lines Using Formal. Ebru Narli, Kadir Sari Oz in Structure (2004). 2 readers Save reference to library · Related research. NURBS skinning surface for ship ...
Given a tetrahedral mesh immersed in a voxel model, we present a method to refine the mesh to red... more Given a tetrahedral mesh immersed in a voxel model, we present a method to refine the mesh to reduce the discrepancy between interpolated values based on either scheme at arbitrary locations. An advantage of the method presented is that it requires few subdivisions and all decisions are made locally at each tetrahedron. We discuss the algorithm's performance and applications.
Example-guided segmentation
Graphical Models, 2012
ABSTRACT In this paper, we propose a novel strategy to automatically segment volume data using a ... more ABSTRACT In this paper, we propose a novel strategy to automatically segment volume data using a high-quality mesh segmentation of an “example” model as a guiding example. The example mesh is deformed until it matches the relevant volume features. The algorithm starts from a medical volume model (scalar field of densities) to be segmented, together with an already existing segmentation (polygonal mesh) of the same organ, usually from a different person. The pre-process step computes a suitable attracting scalar field in the volume model. After an approximate 3D registration between the example mesh and the volume (this is the only step requiring user intervention), the algorithm works by minimizing an energy and adapts the shape of the polygonal mesh to the volume features in order to segment the target organ. The resulting mesh adapts to the volume features in the areas which can be unambiguously segmented, while taking the shape of the example mesh in regions which lack relevant volume information. The paper discusses several examples involving human foot bones, with results that clearly outperform present segmentation schemes.
In many application areas, it is useful to convert the discrete information stored in the nodes o... more In many application areas, it is useful to convert the discrete information stored in the nodes of a regular grid into a continuous boundary model. Isosurface extraction algorithms differ on how the discrete information in the grid is generated, on what information does the grid store and on the properties of the output surface. Recent algorithms offer different solutions for the disambiguation problem and for controlling the final topology. Based on a number of properties of the grid's grey cells and of the reconstruction algorithms, a characterization of several surface extraction strategies is proposed. The classification presented shows the inherent limitations of the different algorithms concerning global topology control and reconstruction of local features like thin portions of the volume and almost non-manifold regions. These limitations can be observed and are illustrated with some practical examples. We review in light of this classification some of the relevant papers in the literature, and see that they cluster in some areas of the proposed hierarchy, making a case for where it might be more interesting to focus in future research.
Computer Graphics Forum, 2007
Given a tetrahedral mesh immersed in a voxel model, we present a method to refine the mesh to red... more Given a tetrahedral mesh immersed in a voxel model, we present a method to refine the mesh to reduce the discrepancy between interpolated values based on either scheme at arbitrary locations. An advantage of the method presented is that it requires few subdivisions and all decisions are made locally at each tetrahedron. We discuss the algorithm's performance and applications.
Computer-Aided Design, 2005
SAMBA: Steadied choreographies
Given the start positions of a group of dancers, a choreographer specifies their end positions an... more Given the start positions of a group of dancers, a choreographer specifies their end positions and says:" Run!" Each dancer has the choice of his/her motion. These choices influence the perceived beauty (or grace) of the overall choreography. We report experiments with an automatic approach, SAMBA, that computes a pleasing choreography. Rossignac and Vinacua focused on affine motions, which, in the plane, correspond to choreographies for three independent dancers. They proposed the inverse of the Average ...
Omni-directionalReliefImpostors
Relief impostors have been proposed as a compact and high-quality representation for high-frequen... more Relief impostors have been proposed as a compact and high-quality representation for high-frequency detail in 3D models. In this paper we propose an algorithm to represent a complex object through the combination of a reduced set of relief maps. These relief maps can be rendered with very few artifacts and no apparent deformation from any view direction. We present an
International Journal of Shape Modeling, 2004
Modern adquisition techniques provide 3D datasets with unprecedented detail. Both triangle-based ... more Modern adquisition techniques provide 3D datasets with unprecedented detail. Both triangle-based and point-based techniques have been proposed for efficient rendering of these objects. We present a new technique for interactive visualization of volumetric data which combines polygonal faces for flat areas and oriented points for curved regions. The paper focuses on extracting large polygonal faces from voxel data. The key ingredient is a region-growing algorithm which maintains a discrete representation of the set of planes that satisfy a separability problem. A robust representation of this set of planes based on a discretized 4D convex polytope is also discussed. The proposed face extraction algorithm is able to recover information at sub-voxel precision and automatically detects sharp edges.
Diseño de curvas y superficies
dialnet.unirioja.es
... | Ayuda. Diseño de curvas y superficies. Autores: Alvar Vinacua Pla; Localización: Informátic... more ... | Ayuda. Diseño de curvas y superficies. Autores: Alvar Vinacua Pla; Localización: Informática gráfica / coord. por Pascual González López, Jesús García-Consuegra Bleda, 1998, ISBN 84-89958-23-8 , pags. 139-157; Recoge ...
We discuss the design and implementation of a software development platform that allows unsophist... more We discuss the design and implementation of a software development platform that allows unsophisticated programmers to include advanced features to their applications with no or very little extra information and e ort. These features include the splitting of the application in distinct processes that may be distributed over a network, a powerful con guration and scripting language, and several tools including an input system to easily construct reasonable interfaces. We attempt to describe both the techniques used to achieve transparency for the programmer and what exactly a user must do to build new Atlas modules.
ACM Transactions on Graphics (TOG), Jan 1, 2011
We propose to measure the beauty of an affine motion by the inverse of its steadiness, which we d... more We propose to measure the beauty of an affine motion by the inverse of its steadiness, which we define as its Average Relative Acceleration (ARA). Steady affine motions, for which ARA= 0, include translations, rotations, screws, and the golden spiral. To facilitate the design of beautiful in-betweening motions that interpolate between an initial and a final pose (affine transformation), B and C, we propose the Steady Affine Morph
Int. J. Shape Modeling, Jan 1, 2004
The NSF Invitational Workshop on Distributed Information, Computation, and Process Management for... more The NSF Invitational Workshop on Distributed Information, Computation, and Process Management for Scientific and Engineering Environments (DICPM) brought together domain specialists from engineering and the ocean, atmospheric, and space sciences involved in the development and use of simulations of complex systems, and computer scientists working on distributed repositories, visualization, and resource management. The objective was to formulate directions for research efforts to facilitate effective collaboration and to help increase access to information and sharing of results and tools useful in large-scale, distributed, multidisciplinary scientific and engineering environments. Three broad problem areas inhibit such activities: (1) Computational, e.g, insufficient infrastructure for the sharing of very large amounts of information, results, and tools; (2) Structural institutional barriers, e.g., funding, publication, and promotion policies; and (3) Social, e.g., communication barriers stemming from narrow specialization. The participants supported specific steps to address these problems: explicit support and incentives for multidisciplinary activities; the development of digitial libraries to enhance interdisciplinary communication and understanding; and development of a "virtual scientific marketplace" to disseminate tools, results, and expertise;
Example-guided segmentation
Modern adquisition techniques provide 3D datasets with unprecedented detail. Both triangle-based ... more Modern adquisition techniques provide 3D datasets with unprecedented detail. Both triangle-based and point-based techniques have been proposed for efficient rendering of these objects. We present a new technique for interactive visualization of volumetric data which combines polygonal faces for flat areas and oriented points for curved regions. The paper focuses on extracting large polygonal faces from voxel data. The key ingredient is a region-growing algorithm which maintains a discrete representation of the set of planes that satisfy a separability problem. A robust representation of this set of planes based on a discretized 4D convex polytope is also discussed. The proposed face extraction algorithm is able to recover information at sub-voxel precision and automatically detects sharp edges.
A Construction for VC1 Continuity of Rational Bézier Patches
Mathematical Methods in Computer Aided Geometric Design, 1989
Modeling Closed Surfaces: A Comparison of Existing Methods
Mathematical Methods in Computer Aided Geometric Design II, 1992
The cage-based deformation of a 3D object through generalized barycentric coordinates is a simple... more The cage-based deformation of a 3D object through generalized barycentric coordinates is a simple, ecient, eective and hence widely used shape manipulation scheme. Editing vertices of the polyhedral cage induces a smooth space deformation of its interior; the vertices thus become control handles of thenal deformation. However, in some application elds, as medicine, constrained volumepreserving deformations are required.
Surface fairing for ship hull design application
Mathematical Engineering in Industry
... reference to library · Related research. The Automated Fairing of Ship Hull Lines Using Forma... more ... reference to library · Related research. The Automated Fairing of Ship Hull Lines Using Formal. Ebru Narli, Kadir Sari Oz in Structure (2004). 2 readers Save reference to library · Related research. NURBS skinning surface for ship ...
Given a tetrahedral mesh immersed in a voxel model, we present a method to refine the mesh to red... more Given a tetrahedral mesh immersed in a voxel model, we present a method to refine the mesh to reduce the discrepancy between interpolated values based on either scheme at arbitrary locations. An advantage of the method presented is that it requires few subdivisions and all decisions are made locally at each tetrahedron. We discuss the algorithm's performance and applications.
Example-guided segmentation
Graphical Models, 2012
ABSTRACT In this paper, we propose a novel strategy to automatically segment volume data using a ... more ABSTRACT In this paper, we propose a novel strategy to automatically segment volume data using a high-quality mesh segmentation of an “example” model as a guiding example. The example mesh is deformed until it matches the relevant volume features. The algorithm starts from a medical volume model (scalar field of densities) to be segmented, together with an already existing segmentation (polygonal mesh) of the same organ, usually from a different person. The pre-process step computes a suitable attracting scalar field in the volume model. After an approximate 3D registration between the example mesh and the volume (this is the only step requiring user intervention), the algorithm works by minimizing an energy and adapts the shape of the polygonal mesh to the volume features in order to segment the target organ. The resulting mesh adapts to the volume features in the areas which can be unambiguously segmented, while taking the shape of the example mesh in regions which lack relevant volume information. The paper discusses several examples involving human foot bones, with results that clearly outperform present segmentation schemes.
In many application areas, it is useful to convert the discrete information stored in the nodes o... more In many application areas, it is useful to convert the discrete information stored in the nodes of a regular grid into a continuous boundary model. Isosurface extraction algorithms differ on how the discrete information in the grid is generated, on what information does the grid store and on the properties of the output surface. Recent algorithms offer different solutions for the disambiguation problem and for controlling the final topology. Based on a number of properties of the grid's grey cells and of the reconstruction algorithms, a characterization of several surface extraction strategies is proposed. The classification presented shows the inherent limitations of the different algorithms concerning global topology control and reconstruction of local features like thin portions of the volume and almost non-manifold regions. These limitations can be observed and are illustrated with some practical examples. We review in light of this classification some of the relevant papers in the literature, and see that they cluster in some areas of the proposed hierarchy, making a case for where it might be more interesting to focus in future research.
Computer Graphics Forum, 2007
Given a tetrahedral mesh immersed in a voxel model, we present a method to refine the mesh to red... more Given a tetrahedral mesh immersed in a voxel model, we present a method to refine the mesh to reduce the discrepancy between interpolated values based on either scheme at arbitrary locations. An advantage of the method presented is that it requires few subdivisions and all decisions are made locally at each tetrahedron. We discuss the algorithm's performance and applications.
Computer-Aided Design, 2005
SAMBA: Steadied choreographies
Given the start positions of a group of dancers, a choreographer specifies their end positions an... more Given the start positions of a group of dancers, a choreographer specifies their end positions and says:" Run!" Each dancer has the choice of his/her motion. These choices influence the perceived beauty (or grace) of the overall choreography. We report experiments with an automatic approach, SAMBA, that computes a pleasing choreography. Rossignac and Vinacua focused on affine motions, which, in the plane, correspond to choreographies for three independent dancers. They proposed the inverse of the Average ...
Omni-directionalReliefImpostors
Relief impostors have been proposed as a compact and high-quality representation for high-frequen... more Relief impostors have been proposed as a compact and high-quality representation for high-frequency detail in 3D models. In this paper we propose an algorithm to represent a complex object through the combination of a reduced set of relief maps. These relief maps can be rendered with very few artifacts and no apparent deformation from any view direction. We present an
International Journal of Shape Modeling, 2004
Modern adquisition techniques provide 3D datasets with unprecedented detail. Both triangle-based ... more Modern adquisition techniques provide 3D datasets with unprecedented detail. Both triangle-based and point-based techniques have been proposed for efficient rendering of these objects. We present a new technique for interactive visualization of volumetric data which combines polygonal faces for flat areas and oriented points for curved regions. The paper focuses on extracting large polygonal faces from voxel data. The key ingredient is a region-growing algorithm which maintains a discrete representation of the set of planes that satisfy a separability problem. A robust representation of this set of planes based on a discretized 4D convex polytope is also discussed. The proposed face extraction algorithm is able to recover information at sub-voxel precision and automatically detects sharp edges.
Diseño de curvas y superficies
dialnet.unirioja.es
... | Ayuda. Diseño de curvas y superficies. Autores: Alvar Vinacua Pla; Localización: Informátic... more ... | Ayuda. Diseño de curvas y superficies. Autores: Alvar Vinacua Pla; Localización: Informática gráfica / coord. por Pascual González López, Jesús García-Consuegra Bleda, 1998, ISBN 84-89958-23-8 , pags. 139-157; Recoge ...
We discuss the design and implementation of a software development platform that allows unsophist... more We discuss the design and implementation of a software development platform that allows unsophisticated programmers to include advanced features to their applications with no or very little extra information and e ort. These features include the splitting of the application in distinct processes that may be distributed over a network, a powerful con guration and scripting language, and several tools including an input system to easily construct reasonable interfaces. We attempt to describe both the techniques used to achieve transparency for the programmer and what exactly a user must do to build new Atlas modules.
ACM Transactions on Graphics (TOG), Jan 1, 2011
We propose to measure the beauty of an affine motion by the inverse of its steadiness, which we d... more We propose to measure the beauty of an affine motion by the inverse of its steadiness, which we define as its Average Relative Acceleration (ARA). Steady affine motions, for which ARA= 0, include translations, rotations, screws, and the golden spiral. To facilitate the design of beautiful in-betweening motions that interpolate between an initial and a final pose (affine transformation), B and C, we propose the Steady Affine Morph
Int. J. Shape Modeling, Jan 1, 2004