Examinando por Autor "Cadavid C."

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    Ítem
    Level sets of weak-morse functions for triangular mesh slicing
    (MDPI AG, 2020-01-01) Mejia-Parra D.; Ruiz-Salguero O.; Cadavid C.; Moreno A.; Posada J.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    In the context of CAD CAM CAE (Computer-Aided Design, Manufacturing and Engineering) and Additive Manufacturing, the computation of level sets of closed 2-manifold triangular meshes (mesh slicing) is relevant for the generation of 3D printing patterns. Current slicing methods rely on the assumption that the function used to compute the level sets satisfies strong Morse conditions, rendering incorrect results when such a function is not a Morse one. To overcome this limitation, this manuscript presents an algorithm for the computation of mesh level sets under the presence of non-Morse degeneracies. To accomplish this, our method defines weak-Morse conditions, and presents a characterization of the possible types of degeneracies. This classification relies on the position of vertices, edges and faces in the neighborhood outside of the slicing plane. Finally, our algorithm produces oriented 1-manifold contours. Each contour orientation defines whether it belongs to a hole or to an external border. This definition is central for Additive Manufacturing purposes. We set up tests encompassing all known non-Morse degeneracies. Our algorithm successfully processes every generated case. Ongoing work addresses (a) a theoretical proof of completeness for our algorithm, (b) implementation of interval trees to improve the algorithm efficiency and, (c) integration into an Additive Manufacturing framework for industry applications. © 2020 by the authors.
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    Ítem
    Mesh Segmentation and Texture Mapping for Dimensional Inspection inWeb3D
    (Association for Computing Machinery, Inc, 2017-01-01) Mejia D.; Sánchez J.R.; Segura Á.; Ruiz-Salguero O.; Posada J.; Cadavid C.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    Traditionally, the data generated by industrial metrology so.ware is stored as static reports that metrology experts produce for engineering and production departments. Nevertheless, industry demands new approaches that provide ubiquitous and real time access to overall geometry, manufacturing and other data. Web3D technologies can help to improve the traditional metrology methods and o.er new ways to convey this information in web-based continuous friendly manner. However, enriched point clouds may be massive, thus presenting transmission and display limitations. To partially overcome these limitations, this article presents an algorithm that computes efficient metrology textures, which are then transferred and displayed through Web3D standards. Texture coordinates are computed only once for the reference CAD mesh on the server using in-house thermal-based segmentation and Hessian-based parameterization algorithms. The metrology data is then encoded in a texture le, which becomes available instantly for interactive visual inspection through the Web3D platform. © 2017 ACM.
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    Ítem
    Quasi-isometric mesh parameterization using heat-based geodesics and poisson surface fills
    (MDPI AG, 2019-01-01) Mejia-Parra D.; Sánchez J.R.; Posada J.; Ruiz-Salguero O.; Cadavid C.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    In the context of CAD, CAM, CAE, and reverse engineering, the problem of mesh parameterization is a central process. Mesh parameterization implies the computation of a bijective map ? from the original mesh M ? R3 to the planar domain ?(M) ? R2. The mapping may preserve angles, areas, or distances. Distance-preserving parameterizations (i.e., isometries) are obviously attractive. However, geodesic-based isometries present limitations when the mesh has concave or disconnected boundary (i.e., holes). Recent advances in computing geodesic maps using the heat equation in 2-manifolds motivate us to revisit mesh parameterization with geodesic maps. We devise a Poisson surface underlying, extending, and filling the holes of the mesh M. We compute a near-isometric mapping for quasi-developable meshes by using geodesic maps based on heat propagation. Our method: (1) Precomputes a set of temperature maps (heat kernels) on the mesh; (2) estimates the geodesic distances along the piecewise linear surface by using the temperature maps; and (3) uses multidimensional scaling (MDS) to acquire the 2D coordinates that minimize the difference between geodesic distances on M and Euclidean distances on R2. This novel heat-geodesic parameterization is successfully tested with several concave and/or punctured surfaces, obtaining bijective low-distortion parameterizations. Failures are registered in nonsegmented, highly nondevelopable meshes (such as seam meshes). These cases are the goal of future endeavors. © 2019 by the authors.
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    Ítem
    Reconfigurable 3D CAD feature recognition supporting confluent n-dimensional topologies and geometric filters for prismatic and curved models
    (MDPI AG, 2020-01-01) Pareja-Corcho J.; Betancur-Acosta O.; Posada J.; Tammaro A.; Ruiz-Salguero O.; Cadavid C.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    Feature Recognition (FR) in Computer-aided Design (CAD) models is central for Design and Manufacturing. FR is a problem whose computational burden is intractable (NP-hard), given that its underlying task is the detection of graph isomorphism. Until now, compromises have been reached by only using FACE-based geometric information of prismatic CAD models to prune the search domain. Responding to such shortcomings, this manuscript presents an interactive FR method that more aggressively prunes the search space with reconfigurable geometric tests. Unlike previous approaches, our reconfigurable FR addresses curved EDGEs and FACEs. This reconfigurable approach allows enforcing arbitrary confluent topologic and geometric filters, thus handling an expanded scope. The test sequence is itself a graph (i.e., not a linear or total-order sequence). Unlike the existing methods that are FACE-based, the present one permits combinations of topologies whose dimensions are two (SHELL or FACE), one (LOOP or EDGE), or 0 (VERTEX). This system has been implemented in an industrial environment, using icon graphs for the interactive rule configuration. The industrial instancing allows industry based customization and itis faster when compared to topology-based feature recognition. Future work is required in improving the robustness of search conditions, treating the problem of interacting or nested features, and improving the graphic input interface. © 2020 by the authors.
  • No hay miniatura disponible
    Ítem
    Reconfigurable 3D CAD feature recognition supporting confluent n-dimensional topologies and geometric filters for prismatic and curved models
    (MDPI AG, 2020-01-01) Pareja-Corcho J.; Betancur-Acosta O.; Posada J.; Tammaro A.; Ruiz-Salguero O.; Cadavid C.; Pareja-Corcho J.; Betancur-Acosta O.; Posada J.; Tammaro A.; Ruiz-Salguero O.; Cadavid C.; Universidad EAFIT. Departamento de Ciencias; Matemáticas y Aplicaciones
    Feature Recognition (FR) in Computer-aided Design (CAD) models is central for Design and Manufacturing. FR is a problem whose computational burden is intractable (NP-hard), given that its underlying task is the detection of graph isomorphism. Until now, compromises have been reached by only using FACE-based geometric information of prismatic CAD models to prune the search domain. Responding to such shortcomings, this manuscript presents an interactive FR method that more aggressively prunes the search space with reconfigurable geometric tests. Unlike previous approaches, our reconfigurable FR addresses curved EDGEs and FACEs. This reconfigurable approach allows enforcing arbitrary confluent topologic and geometric filters, thus handling an expanded scope. The test sequence is itself a graph (i.e., not a linear or total-order sequence). Unlike the existing methods that are FACE-based, the present one permits combinations of topologies whose dimensions are two (SHELL or FACE), one (LOOP or EDGE), or 0 (VERTEX). This system has been implemented in an industrial environment, using icon graphs for the interactive rule configuration. The industrial instancing allows industry based customization and itis faster when compared to topology-based feature recognition. Future work is required in improving the robustness of search conditions, treating the problem of interacting or nested features, and improving the graphic input interface. © 2020 by the authors.