Approximation methods for post-processing of large data from the finite element analysis

The paper describes efficient methods to post-process results from the finite element analysis. Amount of data produced by the complex analysis is enormous. However, computer performance and memory are limited and commonly-used software tools do not provide ways to post-process data easily. Therefore, some sort of simplification of data has to be used to lower memory consumption and accelerate data loading. This article describes a procedure that replaces discrete values with a set of continuous functions. Each approximation function can be represented by a small number of parameters that are able to describe the character of resulting data closely enough

Case Based Reasoning Support for Adaptive Finite Element Analysis - Mesh Selection for an Integrated System

An Adaptive Finite Element Analysis Integrated System supported through application of Case Based Reasoning (CBR) methodology is being proposed in this paper. The approach is fruitful for selection of an initial mesh from a library of solutions to initiate analysis process, as already tested optimal mesh will have lesser refinement iterations. The optimal mesh distribution, represented by object-oriented method, can be easily adapted to the topology of new problem in same domain. An integrated and universal structural analysis system models human reasoning by forming solutions through the retrieval and adaptation of successful strategies used in the past. Basic insight of two distinct subjects along with resolution of involved issues and integration strategy for development of an intelligent system is elaborated here. The research explains an algorithm for case retrieval and mesh generation procedures based on the principles of mapping method

Compression sans perte de maillages triangulaires adaptée aux applications métrologiques

La compression est un incontournable lorsque des modèles triangulaires 3D massifs doivent être transmis via un réseau de communication. La compression se doit d'être sans perte lorsque les modèles sont utilisés à des fins métrologiques. Cependant, les modèles capturés par scanneurs 3D contiennent généralement des artefacts de numérisation tels que la présence de trous dans le maillage, de petits regroupements distincts de triangles sous forme de surfaces ou de volumes ainsi que de singularités non-manifold (c.-à-d. un sommet appartenant à deux regroupement de triangles distincts). Ces aberrations rendent les techniques de compression standards inaptes à compresser sans échec le modèle. Ce mémoire propose une extension à une technique de compression et décompression sans perte des données topologiques nommée Edgebreaker. Le remplissage des trous par l'addition d'un sommet, l'insertion de faces triangulaires afin de lier les îlots ainsi que la duplication des sommets non-manifold sont proposées comme étapes de prétraitement afin de rendre le modèle compatible avec l'approche standard d'Edgebreaker. Les résultats obtenus démontrent que la solution proposée permet la compression sans perte de modèles hautement bruités à de hauts taux de compression. Les taux de compression résultants obtenus par notre approche se comparent également avec les taux observables pour des modèles sans imperfections compressés par Edgebreaker

Adaptive 3D web-based environment for heterogeneous volume objects.

The Internet was growing fast on the last decade. Interaction and visualisation became an essential feature online. The demand for online modelling and rendering in a real-time, adaptive and interactive manner exceeded the growth and development of the hardware resources including computational power and memories. Building up and accessing an instant 3D Web-based and plugin-free platform started to be a must in order to generate 3D volumes. Modelling and rendering complicated heterogeneous volumes using online applications requires good Internet bandwidth and high computational power. A large number of 3D modelling tools designed to create complicated models in an interactive manner are now available online, the problem of using such tools is that the user needs to acquire a certain level of modelling knowledge In this work, we identify the problem, introduce the theoretical background and discuss the theory about Web-based modelling and rendering, including client- server approach, scenario optimization by solving constraint satisfaction problem, and complexity analysis. We address the challenges of designing, implementing and testing an online, Web-based, instant 3D modelling and rendering environment and we discuss some of its characteristics including adaptivity, platform independence, interactivity, and easy-to-use after presenting the theoretical part of implementing such an environment. We also introduce platform-independent modelling and rendering environment for complicated heterogeneous volumes with colour attributes based on client- server architecture. The work includes analysis and implementation for different rendering approaches suitable for different kind of users. We also discuss the performance of the proposed environment by comparing the rendering approaches. As an additional feature of our modelling system, we discuss aspects of securing the model transferring between client and the server

Progressive compression of manifold polygon meshes

International audienceThis paper presents a new algorithm for the progressive compression of manifold polygon meshes. The input surface is decimated by several traversals that generate successive levels of detail through a specific patch decimation operator which combines vertex removal and local remeshing. The mesh connectivity is encoded by two lists of Boolean error predictions based on the mesh geometry: one for the inserted edges and the other for the faces with a removed center vertex. The mesh geometry is encoded with a barycentric error prediction of the removed vertex coordinates and a local curvature prediction. We also include two methods that improve the rate-distortion performance: a wavelet formulation with a lifting scheme and an adaptive quantization technique. Experimental results demonstrate the effectiveness of our approach in terms of compression rates and rate-distortion performance

Out-of-core representation of triangle meshes for rendering of large data volumes

Orientador: Hélio PedriniDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Malhas triangulares são representações de dados espaciais comumente utilizadas na manipulação e visualização de superfícies complexas. Este trabalho apresenta e avalia uma proposta de representação out-of-core estática de malhas de triângulos tridimensionais, a qual permite a consulta de vértices e triângulos adjacentes em tempo constante e o acesso aleatório aos vértices e triângulos da malha, requerendo pouco espaço em memória principal. A característica out-of-core da representação consiste no fato de que apenas as informações necessárias para a aplicação são carregadas em memória primária, ficando o restante armazenado em memória secundária. A representação é estática no sentido de que, ao ocorrer qualquer alteração topológica, ela deverá ser reconstruída novamente. Experimentos são realizados em vários modelos de malhas de triângulos para demonstrar a eficácia da metodologia propostaAbstract: Triangular meshes are spatial data representations commonly used in the manipulation and visualization of complex surfaces. This work proposes and evaluates a static out-of-core representation of three-dimensional triangle meshes, which allows the query of adjacent vertices and triangles in constant time and the random access to the vertices and triangles of the mesh, requiring little space in main memory. The out-of-core feature of the representation consists in the fact that only the necessary information for the application is loaded into primary memory, such that the remainder is stored in secondary memory. The representation is static in the sense that when any topological change occurs, it must be rebuilt again. Experiments are conducted on several triangle mesh models to demonstrate the efficacy of the proposed methodologyMestradoCiência da ComputaçãoMestre em Ciência da Computaçã