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  • Contribution to Structural Parameters Computation: Volume Models and Methods

     Cruz Matias, Irving Alberto
    Defense's date: 2014-01-13
    Universitat Politècnica de Catalunya
    Theses

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    El Bio-Diseño Asistido por Computadora (Bio-CAD), y la experimentación in-silico están teniendo un creciente interés en aplicaciones biomédicas, en donde se utilizan datos científicos provenientes de muestras reales para calcular parámetros estructurales que permiten evaluar propiedades físicas. Las tecnologías de adquisición de imagen no invasivas como la TC, mTC o IRM, y el crecimiento constante de las prestaciones de las computadoras, permiten la adquisición, procesamiento y visualización de datos científicos con creciente grado de complejidad.El cálculo de parámetros estructurales está basado en la existencia de dos fases (o espacios) en la muestra: la sólida, que puede corresponder al hueso o material, y la fase porosa o vacía, por tanto, tales muestras son representadas como volúmenes binarios. El modelo de representación más común para estos conjuntos de datos es el modelo de vóxeles, el cuál es una extensión natural a 3D de los mapas de bits 2D. En esta tesis se utilizan el modelo Extreme Verrtices Model (EVM) y un nuevo modelo propuesto, the Compact Union of Disjoint Boxes (CUDB), para representar los volúmenes binarios en una forma mucho más compacta. El modelo EVM almacena sólo un subconjunto ordenado de vértices de la frontera del objeto mientras que el modelo CUDB mantiene una lista compacta de cajas.En esta tesis se proponen métodos para calcular los siguientes parámetros estructurales: distribución del tamaño de los poros, conectividad, orientación, esfericidad y redondez. La distribución del tamaño de los poros ayuda a interpretar las características de las muestras porosas permitiendo a los usuarios observar los rangos de diámetro más comunes de los poros mediante picos en un gráfica. La conectividad es una propiedad topológica relacionada con el género del espacio sólido, mide el nivel de interconectividad entre los elementos, y es un indicador de las características biomecánicas del hueso o de otros materiales. La orientación de un objeto puede ser definida por medio de ángulos de rotación alrededor de un conjunto de ejes ortogonales. La esfericidad es una medida de que tan esférica es una partícula , mientras que la redondez es la medida de la nitidez de sus aristas y esquinas.En el estudio de estos parámetros se trabaja con muestras reales escaneadas a alta resolución que suelen generar conjuntos de datos enormes, los cuales requieren una gran cantidad de memoria y mucho tiempo de procesamiento para ser analizados. Por esta razón, se presenta un nuevo método para simplificar volúmenes binarios de una manera progresiva y sin pérdidas. Este método genera una secuencia de niveles de detalle de los objetos, en donde cada objeto es un volumen englobante de los objetos previos. Además de ser utilizado como apoyo en el cálculo de parámetros estructurales, este método puede ser de utilizado en otras tareas como transmisión progresiva, detección de colisiones y cálculo de volumen de interés.Como parte de una investigación multidisciplinaria, se han desarrollado dos aplicaciones prácticas para calcular parámetros estructurales de muestras reales. Un software para la detección automática de puntos de viscosidad característicos en muestras de rocas de basalto y vidrios, y una aplicación para calcular la esfericidad y redondez de formas complejas en un conjunto de datos de sílice.

  • Skeletal representations of orthogonal shapes

     Martinez Bayona, Jonas; Pla Garcia, Nuria; Vigo Anglada, Marc
    Graphical models
    Date of publication: 2013-07-01
    Journal article

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    Orthogonal shapes are polygons or polyhedra enclosed by axis-aligned edges or faces, respectively. In this paper we present two skeletal representations of orthogonal shapes: the cube skeleton and a family of skeletal representations provided by the scale cube skeleton. Both skeletal representations rely on the L1 metric. We show that the cube skeleton is homotopically equivalent to its original shape, reduces its dimension, and it is composed of line segments or planar polygons with restricted orientation. We also present an algorithm to compute the scale cube skeleton of orthogonal polygons and compare the presented skeletons with other skeletal representations.

    Orthogonal shapes are polygons orpolyhedra enclosed byaxis-aligned edges orfaces, respectively. Inthis paper wepresent two skeletal representatio nsoforthogonal shapes: the cube skeleton and a family ofskeletal represe ntations provided bythe scale cube skeleton. Both skeletal represe ntations rely onthe L1 metric. Weshow that the cube skeleton is homotopically equivalent to its original shape,reduces its dimension,and it is composed of line segments orplanar polygons with restricted orientation. We also present analgorithm to compute the scale cube skeleton oforthogonal polygons and compare the presented skeletons with other skeletal represe ntations.

  • Skeletal representations of orthogonal shapes

     Martinez Bayona, Jonas
    Defense's date: 2013-12-12
    Universitat Politècnica de Catalunya
    Theses

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    L'esquelet d'un objecte representa propietats topològiques i geomètriques de l'objecte i alhora redueix la seva dimensió. Els esquelets s'utilitzen en diversos àmbits de la ciència i atreuen l'atenció de nombrosos investigadors. En l'àmbit del biocad, l'anàlisi de propietats estructurals com ara la porositat dels biomaterials requereix el càlcul previ de l'esquelet. A mesura que les imatges 3D es fan més grans, es requereixen algorismes eficients i robusts que calculin esquelets més simples. L'esquelet més popular és el medial axis, definit com el conjunt de punts de l'objecte que tenen almenys dos punts més propers en la frontera de l'objecte. Malauradament el medial axis és molt sensible a petites pertorbacions de la frontera de l'objecte. És a dir, un petit canvi en la frontera de l'objecte pot implicar un canvi considerable del seu medial axis. A més, el càlcul exacte del medial axis només és possible per determinats tipus d'objectes. Per exemple, el medial axis dels poliedres té una estructura no lineal i és difícil de calcular de manera robusta. Aquests problemes van motivar l'aparició d'aproximacions del medial axis. Existeixen dos mètodes d'aproximació principals: aquells en què l'objecte s'aproxima amb un altre classe d'objecte i aquells en què la mètrica Euclidiana es substitueix per una altra mètrica aproximada.La principal aportació d'aquesta tesi és la simplificació conjunta, a l'hora de calcular l'esquelet, de l'objecte d'entrada i de la mètrica considerada. L'objecte d'entrada s'aproxima amb un objecte ortogonal, que són polígons o poliedres delimitats per segments o cares, respectivament, paral·lels als eixos de coordenades o plans coordenats. En el mateix sentit, la mètrica Euclidiana es substitueix per la mètrica L infinit o mètrica de Chebyshev. Tot i la seva estructura simple, existeixen pocs treballs en la literatura sobre esquelets d'objectes ortogonals. Gran part dels esforços s'han dedicat a imatges i volums binaris, que són un subconjunt dels objectes ortogonals. En aquesta tesi s'introdueixen dos nous tipus d'esquelet basats en aquest paradigma: el cube skeleton i el scale cube skeleton. El cube skeleton es compon de segments rectes o cares planes i és homotopicament equivalent a l'objecte d'entrada. El scale cube skeleton es basa en el cube skeleton i presenta una família d'esquelets que són menys sensibles a pertorbacions de la frontera de l'objecte. A més, es presenten els algorismes necessaris per calcular el cube skeleton de polígons i poliedres així com el scale cube skeleton de polígons. Diversos resultats experimentals confirmen l'eficiència, la robustesa i l'aplicació pràctica de tots els mètodes presentats.

  • Efficient algorithms for boundary extraction of 2D and 3D orthogonal pseudomanifolds

     Vigo Anglada, Marc; Pla Garcia, Nuria; Ayala Vallespi, M. Dolors; Martinez Bayona, Jonas
    Graphical models
    Date of publication: 2012
    Journal article

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    In this paper we present algorithms to extract the boundary representation of orthogonal polygons and polyhedra, either manifold or pseudomanifold. The algorithms we develop reconstruct not only the polygons of the boundaries but also the hole-face inclusion relationship. Our algorithms have a simple input so they can be used to convert many different kinds of models to B-Rep. In the 2D case, the input is the set of vertices, and in the 3D case, some small additional information must be supplied for every vertex. All proposed algorithms run in View the MathML source time and use O(n) space, where n is the number of vertices of the input. Moreover, we explain how to use our proposal to extract the boundary from the well-known voxel and octree models as well as from three vertex-based models found in the related literature: the neighbourhood, the EVM, and the weighted vertex list models.

  • Juegos serios para el entretenimiento de cirugía cardiaca

     Ayala Vallespi, M. Dolors; Pla Garcia, Nuria; Vigo Anglada, Marc; Solano Albajes, Luis; Eguia Gomez, Jose Luis; Grau Carrión, Sergi; Martinez Bayona, Jonas; Tost Pardell, Daniela
    Participation in a competitive project

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  • Skeleton computation of orthogonal polyhedra

     Martínez Bayona, Jonàs; Vigo Anglada, Marc; Pla Garcia, Nuria
    Computer graphics forum
    Date of publication: 2011-08
    Journal article

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    Skeletons are powerful geometric abstractions that provide useful representations for a number of geometric operations. The straight skeleton has a lower combinatorial complexity compared with the medial axis. Moreover, while the medial axis of a polyhedron is composed of quadric surfaces the straight skeleton just consist of planar faces. Although there exist several methods to compute the straight skeleton of a polygon, the straight skeleton of polyhedra has been paid much less attention. We require to compute the skeleton of very large datasets storing orthogonal polyhedra. Furthermore, we need to treat geometric degeneracies that usually arise when dealing with orthogonal polyhedra. We present a new approach so as to robustly compute the straight skeleton of orthogonal polyhedra. We follow a geometric technique that works directly with the boundary of an orthogonal polyhedron. Our approach is output sensitive with respect to the number of vertices of the skeleton and solves geometric degeneracies. Unlike the existing straight skeleton algorithms that shrink the object boundary to obtain the skeleton, our algorithm relies on the plane sweep paradigm. The resulting skeleton is only composed of axis-aligned and 45 rotated planar faces and edges.

  • Skeleton computation of an image using a geometric approach

     Martínez Bayona, Jonàs; Vigo Anglada, Marc; Pla Garcia, Nuria; Ayala Vallespi, M. Dolors
    Annual Conference of the European Association for Computer Graphics
    Presentation's date: 2010-05
    Presentation of work at congresses

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    In this work we develop two algorithms to compute the skeleton of a binary 2D image. Both algorithms follow a geometric approach and work directly with the boundary of the image which is an orthogonal polygon (OP). One of these algorithms processes the edges of the polygon while the other one uses its vertices. Compared with a thinning method, the presented algorithms show a good performance. This is a work in progress as our final goal is to extend the vertex-based algorithm method to 3D in order to compute the surface skeleton of a binary volume.

  • Modelado, análisis y visualización de características de datos volumétricos en ingeniería biomédica

     Martinez Bayona, Jonas; Tost Pardell, Daniela; Pla Garcia, Nuria; Puig Puig, Ana; Vigo Anglada, Marc; Grau Carrión, Sergi; Verges Garcia, Eduard; Cruz Matias, Irving Alberto; Ferré Bergadà, Maria; Ayala Vallespi, M. Dolors
    Participation in a competitive project

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  • Splat representation of parametric surfaces

     Ayala Vallespi, M. Dolors; Pla Garcia, Nuria; Vigo Anglada, Marc
    Computing
    Date of publication: 2007-04
    Journal article

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  • Fonaments de programació ii

     Ayala Vallespi, M. Dolors; Pla Garcia, Nuria; Soto Riera, Antoni; Vigo Anglada, Marc; Vilaplana Pastó, Josep
    Date of publication: 2006-02-28
    Book

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  • N-Sided patches with B-Spline boundaries

     Pla Garcia, Nuria; Vigo Anglada, Marc; Cotrina Navau, Josep
    Computers & graphics
    Date of publication: 2006-12
    Journal article

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  • Splat representation of parametric surfaces

     Ayala Vallespi, M. Dolors; Pla Garcia, Nuria; Vigo Anglada, Marc
    Date: 2005-09
    Report

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  • Multisided patches

     Pla Garcia, Nuria; Vigo Anglada, Marc; Cotrina Navau, Josep
    Date: 2004-06
    Report

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  • Two triangulation methods based on edge refinement

     Vigo Anglada, Marc; Pla Garcia, Nuria; Ayala Vallespi, M. Dolors
    Computing
    Date of publication: 2004-05
    Journal article

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  • Two triangulations methods based on edge refinement

     Ayala Vallespi, M. Dolors; Pla Garcia, Nuria; Vigo Anglada, Marc
    Date: 2003-03
    Report

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  • EFFICIENT TECHNIQUES IN GLOBAL LINE RADIOSITY

     CASTRO VILLEGAS, FRANCISCO
    Defense's date: 2002-12-09
    Department of Software, Universitat Politècnica de Catalunya
    Theses

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  • MAT2002-04297-C03-02 SIMULACION 3D DE IMPLANTES DE BIOMATERIALES EN ESTRUCTURA OSEA.

     Ayala Vallespi, M. Dolors; Tost Pardell, Daniela; Vigo Anglada, Marc; Franquesa Niubo, Marta; Pla Garcia, Nuria; Ferré Bergadà, Maria; Puig Puig, Ana
    Participation in a competitive project

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  • A generic approach to free form surface generation

     Cotrina Navau, Josep; Pla Garcia, Nuria; Vigo Anglada, Marc
    7th ACM Symposium on Solid Modelling and Applications
    Presentation of work at congresses

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  • Regular triangulations of dynamic sets of points

     Vigo Anglada, Marc; Pla Garcia, Nuria; Cotrina Navau, Josep
    Computer aided geometric design
    Date of publication: 2002-03
    Journal article

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  • A Generic Approach to Free Form Surface Generation

     Cotrina Navau, Josep; Pla Garcia, Nuria; Vigo Anglada, Marc
    Journal of computing and information science in engineering
    Date of publication: 2002-12
    Journal article

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  • APROXIMACIÓ DE MALLES NO-REGULARS

     Cotrina Navau, Josep
    Defense's date: 2001-12-04
    Department of Software, Universitat Politècnica de Catalunya
    Theses

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  • Towards free form surfaces

     Cotrina Navau, Josep; Pla Garcia, Nuria; Vigo Anglada, Marc
    Date: 2001-03
    Report

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  • N-sided patches with B-spline boundaries

     Cotrina Navau, Josep; Pla Garcia, Nuria; Vigo Anglada, Marc
    Date: 2001-12
    Report

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  • Structural and algorithmic aspects of geometric projections

     ANTONI SELLARES CHIVA, JOAN
    Defense's date: 2000-05-05
    Department of Software, Universitat Politècnica de Catalunya
    Theses

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  • Curvature Adaptive Triangulations of Surfaces

     Vigo Anglada, Marc; Pla Garcia, Nuria; Brunet Crosa, Pere
    Date: 2000-03
    Report

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  • Free Form Surfaces

     Cotrina Navau, Josep; Pla Garcia, Nuria
    Date: 2000-05
    Report

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  • Regular Triangulations of Dynamic Sets of Points

     Vigo Anglada, Marc; Pla Garcia, Nuria
    Date: 2000-10
    Report

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  • Computing directional constrained Delaunay triangulations

     Vigo Anglada, Marc; Pla Garcia, Nuria
    Computers & graphics
    Date of publication: 2000-04
    Journal article

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  • Modelling surfaces from planar irregular meshes

     Cotrina Navau, Josep; Pla Garcia, Nuria
    Computer aided geometric design
    Date of publication: 2000-01
    Journal article

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  • Modelling surfaces from meshes of arbitrary topology

     Cotrina Navau, Josep; Pla Garcia, Nuria
    Computer aided geometric design
    Date of publication: 2000-07
    Journal article

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  • Directional adaptive surface triangulation

     Vigo Anglada, Marc; Pla Garcia, Nuria; Brunet Crosa, Pere
    Computer aided geometric design
    Date of publication: 1999-02
    Journal article

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    Several CAD applications require a surface model of the modeled object consisting of a mesh of triangular facets. In this paper, a new algorithm for triangulation of trimmed surfaces is presented. The algorithm generates a triangulation that approximates the initial surface within a predefined tolerance. The approximation is conformal, without cracks in edges: a closed polyhedron is obtained in the case of a closed initial surface. The proposed algorithm improves the algorithm presented in (Brunet and Vigo, 1995) because it is based on more precise bounds which take into account the directional behavior of local surface curvature, and the resulting triangulation has a lower number of triangles.

  • Computing directional constrained Delaunay triangulations

     Vigo Anglada, Marc; Pla Garcia, Nuria
    Spanish Meeting on Computational Geometry
    Presentation of work at congresses

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  • TIC99-1230-C02-02 INTEGRACIÓN, MODELADO Y VISUALIZACIÓN 3D DE DATOS ANATOMICOS Y FINCIONALES DEL CEREBRO Y DEL CORAZÓN

     Tost Pardell, Daniela; Ayala Vallespi, M. Dolors; Cotrina Navau, Josep; Puig Puig, Ana; Pla Garcia, Nuria
    Participation in a competitive project

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  • Desarrollo de una aplicación CAE para el diseño de circuitos de ventilación

     Ayala Vallespi, M. Dolors; Pla Garcia, Nuria; Soto Riera, Antoni; Vigo Anglada, Marc; Vila Marta, Sebastian
    IX Congreso Español de Informática Gráfica
    Presentation of work at congresses

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  • Desarrollo de una aplicación CAE para el diseño de circuitos de ventilación

     Ayala Vallespi, M. Dolors; Pla Garcia, Nuria; Soto Riera, Antoni; Vigo Anglada, Marc; Vila Marta, Sebastian
    Date: 1999-07
    Report

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  • Surface fairing for ship hull design applications

     Brunet Crosa, Pere; Vinacua Pla, Alvaro; Pla Garcia, Nuria; Vivo Lorenzo, Manuel
    Mathematical engineering in Industry
    Date of publication: 1998-10
    Journal article

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  • Triangulación adaptativa de superfícies paramétricas

     Vigo Anglada, Marc
    Defense's date: 1998-11-30
    Department of Software, Universitat Politècnica de Catalunya
    Theses

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  • Surface Fairing for Ship Hull Design Application.

     Brunet Crosa, Pere; Vinacua Pla, Alvaro; Vivo Lorenzo, Manuel; Pla Garcia, Nuria; Rodríguez, A
    Date: 1998-06
    Report

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  • Modelling Surfaces from Planar Irregular Meshes

     Cotrina Navau, Josep; Pla Garcia, Nuria
    Date: 1998-06
    Report

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  • INFORMATICA ETSEIB. Resolucio d'alguns problemes. Curs 1996-97.

     Pérez Vidal, Luis; Pla Garcia, Nuria
    Date: 1997-09
    Report

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  • Una libreria para el modelado mediante NURBS

     Fumanal Diaz, Javier; Pla Garcia, Nuria; Vinacua Pla, Alvaro
    Congreso Español de Informática Gráfica
    Presentation of work at congresses

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  • From Degenerate Patches to Triangular and Trimmed Patches

     Pla Garcia, Nuria
    Curves & Surfaces
    Presentation's date: 1996-06-26
    Presentation of work at congresses

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  • From Degenerate Patches to Triangular and Trimmed Patches

     Vigo Anglada, Marc; Pla Garcia, Nuria; Brunet Crosa, Pere
    International Conference on Curves and Surfaces
    Presentation's date: 1996
    Presentation of work at congresses

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  • From Degenerate Patches to Triangular and Trimmed Patches

     Vigo Anglada, Marc; Pla Garcia, Nuria; Brunet Crosa, Pere
    Curves and Surfaces
    Presentation of work at congresses

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  • Programació fonamental: pràctiques de laboratori

     Vila Marta, Sebastian; Pla Garcia, Nuria; Solano Albajes, Luis; Soto Riera, Antoni
    Date of publication: 1996-09-01
    Book

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  • NURBS and Face Octrees for Ship Hull Design

     Pla Garcia, Nuria
    GEOMETRIC MODELLING
    Presentation's date: 1996-05-28
    Presentation of work at congresses

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  • Preparació, realització i avaluació de pràctiques de programació

     Martinez Parra, Conrado; Medina Llinas, Manuel; Pérez Vidal, Luis; Pla Garcia, Nuria; Puig Montada, Ana M.; Solano Albajes, Luis
    Date of publication: 1995-01
    Book

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  • TIC95-0630-C05-04 DISEÑO MEDIANTE RESTRICCIONES GEOMETRICAS

     Joan Arinyo, Robert; Soto Riera, Antoni; Vilaplana Pastó, Josep; Solano Albajes, Luis; Garcia Diego, Blanca; Brunet Crosa, Pere; Pérez Vidal, Luis; Pla Garcia, Nuria
    Participation in a competitive project

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  • TIC95-0630-C05-03 DISEÑO DE SOLIDOS Y SUPERFICIES

     Navazo Alvaro, Isabel; Brunet Crosa, Pere; Ayala Vallespi, M. Dolors; Vila Marta, Sebastian; Vigo Anglada, Marc; Esteve Cusine, Jordi; Pla Garcia, Nuria
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  • "FROM DEGENERATE PATCHES TO TRIANGULAR AND TRIMMED PATCHES"

     Vigo Anglada, Marc; Pla Garcia, Nuria; Brunet Crosa, Pere
    Date: 1995-03
    Report

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