Solid Modeling

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Browsing Solid Modeling by Subject "Aided Engineering]"

Now showing 1 - 4 of 4
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    Developability-preserved Free-form Deformation of Assembled Patches
    (The Eurographics Association, 2004) Wang, C. C. L.; Tang, K.; Gershon Elber and Nicholas Patrikalakis and Pere Brunet
    A novel and practical approach is presented in this paper that solves a constrained free-form deformation (FFD) problem where the developability of the tessellated embedded surface patches is preserved during the lattice deformation. The formulated constrained FFD problem has direct application in areas of product design where the surface developability is required, such as clothing, ship hulls, automobile parts, etc. In the proposed approach, the developability-preserved FFD problem is formulated as a constrained optimization problem. Different from other contained FFD approaches, the positions of lattice control points are not modified in our algorithm - as their control is insufficient in regards to the developability of all the nodes in the mesh. Moreover, the optimization is performed on the parameters of the mesh nodes rather than directly modifying their 3D coordinates, which avoids the time-consuming inverse calculation of the parameters of every node in a non-parallelepiped control lattice when further deformations are required.
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    Physics-based Modelling and Simulation of Functional Cloth for Virtual Prototyping Applications
    (The Eurographics Association, 2004) Fontana, M.; Rizzi, C.; Cugini, U.; Gershon Elber and Nicholas Patrikalakis and Pere Brunet
    A CAD-oriented system is proposed for the design of complex-shaped functional cloth, provided with a physics-based modelling core for simulation and virtual prototyping tasks. Textiles are physically modelled as particle grids in 3D space subjected to Newtonian dynamics, with internal spring, bending and shear forces derived from KES-F data measuring material behaviour. Interactions with the environment are expressed as external forces, collisions against obstacles, self-collisions and constraints. Differently from physicsbased animation systems, the proposed system is conceived for real design purposes, and includes functionalities emulating the construction process of actual clothing and structural textiles, e.g., mesh sewing/assembly, insertion of small components, multilayered fabric composition, mechanical shape deformation, and 2D-to-3D mapping methods. As applications, several cases of textile configurations are considered, with geometric models directly provided by industrial companies and presenting different levels of design complexities, such as garment models (e.g., men's jackets) for the clothing sector, or functional textiles used in the automotive industry (e.g., soft car tops).
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    Residual Iteration and Accurate Polynomial Evaluation for Shape-interrogation Applications
    (The Eurographics Association, 2004) Hoffmann, C.; Park, with G.; Simard, J-R.; Stewart, N. F.; Gershon Elber and Nicholas Patrikalakis and Pere Brunet
    Surface interrogation and intersection depend crucially on good root-finding algorithms, which in turn depend on accurate polynomial evaluation. Conventional algorithms for evaluation typically encounter difficulties near multiple roots, or roots that are very close, and this may lead to gross errors in the geometric computation, or even catastrophic failure. In this paper we study the cost and accuracy of several approaches to polynomial evaluation, explaining the reasons for non-convergence of certain methods, and supporting our subsequent conclusions with the results of benchmarking experiments.
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    Topological and Geometric Beautification of Reverse Engineered Geometric Models
    (The Eurographics Association, 2004) Langbein, F. C.; Marshall, A. D.; Martin, R. R.; Mills, B. I.; Gao, C. H.; Gershon Elber and Nicholas Patrikalakis and Pere Brunet
    Boundary representation models reverse engineered from 3D range data suffer from various inaccuracies caused by noise in the measured data and the model building software. Beauti cation aims to improve such models in a post-processing step solely working with the boundary representation model. The improved model should exhibit topological and geometric regularities representing the original, ideal design intent. This paper gives an overview of algorithms for a complete beauti cation system suitable for improving the topology and the geometry of low to medium complexity reverse engineered models.