Direct modification of FE meshes preserving group information

Nowadays, the mainstream methodology for product behavior analysis and improvement relies on the fol-lowing steps: 1) conceptual solution proposal and CAD prototyping, 2) mesh model creation for Finite Element (FE) analysis, 3) preparation of complex mesh model as specification of semantic information for particular behavior study, 4) advanced FE simu-lation, 5) result analysis and optimization loops. The semantics relative to the simulation model are often associated to mesh entities through the use of so-called mesh groups. During the optimization phase, geometric modifications are generally performed on the CAD model. This requires a complete updating of the FE mesh model repeating all the above listed FE mesh preparation (re-creation of all the groups). In the present paper, we propose a new framework for CAD-less FE analysis. It comes to apply shape modi-fication operators directly to the FE mesh while ex-ploiting and maintaining the available FE semantic information. As a result, multiple steeps of the design process loop, as CAD and mesh model generation, mesh group creation, are avoided. In this paper, we focus on two 3D mesh modification operators: the planar cracking and the drillin

Semantic-preserving mesh direct drilling

Advances in modeling of discrete models have allowed the development of approaches for direct mesh modeling and modification. These tools mainly focus on modeling the visual appearance of the shape which is a key criterion for animation or surgical simulation. Most of the time, the resulting mesh quality as well as the semantics preservation capabilities are not considered as key features. These are the limits we overcome in this paper to enable fast and efficient mesh modifications when carrying out numerical simulations of product behaviors using the Finite Element (FE) analysis. In our approach, the modifications involve the resolution of an optimization problem where the constraints come from the shapes of the operating tools and the FE groups (sets of mesh entities) used to support the semantic information (e.g. boundary conditions, materials) contained in the FE mesh model and required for FE simulation. The overall mesh quality, a key point for accurate FE analysis, is guaranteed while minimizing an objective function based on a mechanical model of bar networks which smoothes the repositioning of nodes. Principle of the devised mesh operators is exemplified through the description of a 2D/3D mesh drilling operator. The proposed mesh modification operators are useful in the context of fast maintenance studies and help engineers to assess alternative design solutions aimed at improving the physical behavior of industrial machinery

Semantic-preserving mesh direct drilling

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Semantic-preserving mesh direct drilling

Advances in modeling of discrete models have allowed the development of approaches for direct mesh modeling and modification. These tools mainly focus on modeling the visual appearance of the shape which is a key criterion for animation or surgical simulation. Most of the time, the resulting mesh quality as well as the semantics preservation capabilities are not considered as key features. These are the limits we overcome in this paper to enable fast and efficient mesh modifications when carrying out numerical simulations of product behaviors using the Finite Element (FE) analysis. In our approach, the modifications involve the resolution of an optimization problem where the constraints come from the shapes of the operating tools and the FE groups (sets of mesh entities) used to support the semantic information (e.g. boundary conditions, materials) contained in the FE mesh model and required for FE simulation. The overall mesh quality, a key point for accurate FE analysis, is guaranteed while minimizing an objective function based on a mechanical model of bar networks which smoothes the repositioning of nodes. Principle of the devised mesh operators is exemplified through the description of a 2D/3D mesh drilling operator. The proposed mesh modification operators are useful in the context of fast maintenance studies and help engineers to assess alternative design solutions aimed at improving the physical behavior of industrial machinery

Direct modification of FE meshes preserving group information

Nowadays, the mainstream methodology for product behavior analysis and improvement relies on the fol-lowing steps: 1) conceptual solution proposal and CAD prototyping, 2) mesh model creation for Finite Element (FE) analysis, 3) preparation of complex mesh model as specification of semantic information for particular behavior study, 4) advanced FE simu-lation, 5) result analysis and optimization loops. The semantics relative to the simulation model are often associated to mesh entities through the use of so-called mesh groups. During the optimization phase, geometric modifications are generally performed on the CAD model. This requires a complete updating of the FE mesh model repeating all the above listed FE mesh preparation (re-creation of all the groups). In the present paper, we propose a new framework for CAD-less FE analysis. It comes to apply shape modi-fication operators directly to the FE mesh while ex-ploiting and maintaining the available FE semantic information. As a result, multiple steeps of the design process loop, as CAD and mesh model generation, mesh group creation, are avoided. In this paper, we focus on two 3D mesh modification operators: the planar cracking and the drillin

The aesthetics of science fiction spaceship design

In this thesis, we present a detailed analysis of the conventions that appear in fictional spaceship design, including a discussion of their origins, their uses in emulating certain traits, and reasons these conventions might be followed or ignored. We uncover these conventions by examining and comparing popular spaceship designs from the past sixty years, which we present in a detailed survey. We also examine an aesthetic interpretation of information theory, which can be used to describe the balance of uniformity amidst variety, and discuss specific strategies for incorporating these principles into the creation of spaceship surface details. Procedural modeling describes a set of techniques used to allow computers to generate digital content such as 3D digital models automatically. However, procedural modeling to date has focused on very specific areas: natural scenery such as trees and terrain, or cityscapes such as road maps and buildings. While these types of models are important and useful, they focus on a specific subset of the procedural modeling problem. Though procedural generation can be an invaluable tool for providing viable and dynamic content, it is troubling that so few types of objects have been studied in this area. Using the aesthetic and spaceship principles we define, we have developed a prototype system to procedurally generate the surface details of a large scale spaceship. Given a surface representing the frame of a spaceship, we apply geometry automatically in a coherent manner to achieve the appearance of a spaceship by emulating important traits

Volumetric particle modeling

This dissertation presents a robust method of modeling objects and forces for computer animation. Within this method objects and forces are represented as particles. As in most modeling systems, the movement of objects is driven by physically based forces. The usage of particles, however, allows more artistically motivated behavior to be achieved and also allows the modeling of heterogeneous objects and objects in different state phases: solid, liquid or gas. By using invisible particles to propagate forces through the modeling environment complex behavior is achieved through the interaction of relatively simple components. In sum, 'macroscopic' behavior emerges from 'microscopic' modeling. We present a newly developed modeling framework expanding on related work. This framework allows objects and forces to be modeled using particle representations and provides the details on how objects are created, how they interact, and how they may be displayed. We present examples to demonstrate the viability and robustness of the developed method of modeling. They illustrate the breaking and fracturing of solids, the interaction of objects in different phase states, and the achievement of a reasonable balance between artistic and physically based behaviors

Procedural Modeling of Cracks and Fractures

International audienceThis paper presents a procedural method for modeling cracks and fractures in solid materials such as glass, metal and stone. Existing physically based techniques are computationally demanding and lack control over crack and fracture propagation. Our procedural approach provides the designer with simple tools to control the pattern of the cracks and the size and shape of the fragments. Given a few parameters, our method automatically creates a vast range of types of cracks and fragments of different shapes