A system for constructing boundary representation solid models from a two-dimensional sketch

2000 ◽  
Author(s):  
P.A.C. Varley ◽  
R.R. Martin
Keyword(s):  
Boundary Representation ◽  
Two Dimensional ◽  
Solid Models

scholarly journals An approach to automatic boundary segmentation of solid models using virtual topology: toward reconstruction of design features

2020 ◽  
Vol 7 (3) ◽  
pp. 367-385
Author(s):  
Yingzhong Zhang ◽  
Yufei Fu ◽  
Jia Jia ◽  
Xiaofang Luo
Keyword(s):  
Design Feature ◽  
Boundary Representation ◽  
Virtual Topology ◽  
Design Features ◽  
Complex Part ◽  
Novel Approach ◽  
Solid Models ◽  
Medium Level ◽  
Feature Based ◽  
Low Dimensional

Abstract Boundary segmentation of solid models is the geometric foundation to reconstruct design features. In this paper, based on the shape evolution analysis for the feature-based modeling process, a novel approach to the automatic boundary segmentation of solid models for reconstructing design features is proposed. The presented approach simulates the designer’s decomposing thinking on how to decompose an existing boundary representation model into a set of design features. First, the modeling traces of design features are formally represented as a set of feature vertex adjacent graphs that use low-dimensional vertex entities and their connection relations. Then, a set of Boolean segmentation loops is searched and extracted from the constructed feature vertex adjacent graphs, which segment the boundary of a solid model into a set of regions with different design feature semantics. In the search process, virtual topology operations are employed to simulate the topological changes resulting from Boolean operations in feature modeling processes. In addition, to realize effective search, search strategies and search algorithms are presented. The segmentation experiments and case study show that the presented approach is feasible and effective for the boundary segmentation of medium-level complex part models. The presented approach lays the foundation for the later reconstruction of design features.

Integrating Design Process Knowledge With CAD Models

2001 ◽  
Author(s):  
Erik E. Hayes ◽  
William C. Regli
Keyword(s):  
Design Process ◽  
Computer Aided Design ◽  
Search Space ◽  
Temporal Changes ◽  
Boundary Representation ◽  
Process Knowledge ◽  
Solid Models ◽  
Design And Manufacturing ◽  
Cad Models ◽  
Manufacturing Problems

Abstract Solid models are static entities, often defined by boundary representation models as sets of enclosing surfaces. Constructive Solid Geometry and feature-based computer-aided design environments create procedural descriptions of 3D objects in forms of history or CSG trees. These representations are temporally fixed, i.e., they describe the state of an object at a point in time. This paper describes a method to represent and capture temporal evolution of solid models — what we call model process history. We define process history to be all states of a model — the search space of design process. This paper presents a representational formalism we call model process graphs (MPGs). We use MPGs to integrate a model’s description with a model of temporal changes that occur during the design process. We believe that MPG representations can have valuable application for many design and manufacturing problems. The paper describes our preliminary results to use MPGs to (1) create a record of design process; (2) store process-based design rationale; (3) represent in-process shapes for machined artifacts. We anticipate that similar structures will find application in other design and manufacturing problems where important process knowledge is embodied by temporal changes occurring in model evolution.

Interval Method for Interrogation of Implicit Solid Models

2000 ◽  
Author(s):  
Jack Chang ◽  
Mark Ganter ◽  
Duane Storti
Keyword(s):  
Computer Aided Design ◽  
Boundary Representation ◽  
Free Form ◽  
Solid Models ◽  
Cad Cam ◽  
Implicit Modeling ◽  
Manufacturing Applications ◽  
Determine Surface Area ◽  
Implicit Solid ◽  
Aided Design

Abstract Computer-aided design/manufacturing (CAD/CAM) systems intended to support automated design and manufacturing applications such as shape generation and solid free-form fabrication (SFF) must provide not only methods for creating and editing models of objects to be manufactured, but also methods for interrogating the models. Interrogation refers to any process that derives information from the model. Typical interrogation tasks include determine surface area, volume or inertial properties, computing surface points and normals for rendering, and computing slice descriptions for SFF. While currently available commercial modeling systems generally employ a boundary representation (B-rep) implementation of solid modeling, research efforts have considered implicit modeling schemes as a potential source of improved robustness. Implicit implementations are available for a broad range of modeling operations, but interrogation operations have been widely considered too costly for many applications. This paper describes a method based on interval analysis for interrogating implicit solid models that aims at achieving both robustness and efficiency.

Interval Methods for B-Rep Model Verification and Rectification

2000 ◽  
Author(s):  
Guoling Shen ◽  
Takis Sakkalis ◽  
Nicholas M. Patrikalakis
Keyword(s):  
Interval Arithmetic ◽  
Boundary Representation ◽  
Model Verification ◽  
Interval Methods ◽  
Topological Structures ◽  
Numerical Errors ◽  
Solid Models ◽  
Exact Boundary ◽  
Geometric Consistency ◽  
Model Conversion

Abstract Boundary representation (B-rep) models often have geometric specifications inconsistent with their topological structures due to numerical errors. In this paper, we verify the geometric consistency of B-rep models and evaluate existing inconsistencies of such models using interval arithmetic. Moreover, we convert conventional B-rep models into interval solid models to correct them. An interval solid is defined as a collection of non-degenerate boxes whose union covers the intended exact boundary and is guaranteed to be gap-free. An example illustrates our method for model conversion.

scholarly journals Using the Mask-RCNN Convolutional Neural Network to Automate the Construction of Two-Dimensional Solid Vertebral Models

2020 ◽  
Vol 20 (4) ◽  
pp. 502-516
Author(s):  
Alexander S. Beskrovny ◽  
◽  
Leonid V. Bessonov ◽  
Dmitriy V. Ivanov ◽  
Irina V. Kirillova ◽  
...  
Keyword(s):  
Neural Network ◽  
Computer Aided Design ◽  
Automatic Recognition ◽  
Medical Decision ◽  
Two Dimensional ◽  
Medical Decision Support ◽  
The Neural Network ◽  
Solid Models ◽  
Urgent Task ◽  
Medical Data Processing

Biomechanical modeling requires the construction of an accurate solid model of the object under study based on the data of a particular patient. This problem can be solved manually using modern software packages for medical data processing or using computer-aided design systems. This approach is used by many researchers and allows you to create accurate solid models, but is time consuming. In this regard, the automation of the construction of solid models suitable for performing biomechanical calculations is an urgent task and can be carried out using neural network technologies. This study presents the implementation of one of the methods for processing computed tomography data in order to create two-dimensional accurate solid models of vertebral bodies in a sagittal projection. An artificial neural network Mask-RCNN was used for automatic recognition of vertebrae. The assessment of the quality of the automatic recognition performed by the neural network was carried out on the basis of comparison with the S¨ orensen measure with manual segmentation performed by practitioners. Application of the method makes it possible to significantly speed up the process of modeling bone structures of the spine in 2D mode. The implemented technique was used in the development of a solid-state model module, which is included in the SmartPlan Ortho 2D medical decision support system developed at Saratov State University within the framework of the Advanced Research Foundation project.

Solid Model Streaming As a Basis for a Distributed Design Environment

2000 ◽  
Author(s):  
Di Wu ◽  
Swati Bhargava ◽  
Radha Sarma
Keyword(s):  
The Internet ◽  
Solid Model ◽  
Distributed Design ◽  
Two Dimensional ◽  
Proof Of Concept ◽  
Design Environment ◽  
One Dimensional ◽  
Solid Models ◽  
Storage Complexity ◽  
And Storage

Abstract This paper proposes an algorithm for streaming manifold solid models and NURBS geometry. A neutral streaming representation consisting of a nodes graph is encoded by a one-dimensional dynamic stack. The encoded model is transmitted over the Internet, where a two-dimensional dynamic stack decodes and reconstructs the solid model. The time and storage complexity of the algorithm are investigated. An example of streaming a solid model, resulting from a proof-of-concept implementation, is demonstrated.

Applications of Non-Manifold Topology

1995 ◽  
Author(s):  
William W. Charlesworth ◽  
David C. Anderson
Keyword(s):  
Automatic Generation ◽  
Boundary Representation ◽  
Surface Topology ◽  
Solid Model ◽  
Finite Element Analyses ◽  
Topological Constraints ◽  
Tool Paths ◽  
Solid Models ◽  
New Applications ◽  
Complicated Surface

Abstract It is widely recognized that a solid model based on a non-manifold boundary representation can have a more complicated surface topology than one based on a manifold boundary representation, but non-manifold topology has other capabilities that may be more valuable to the application developer. Non-manifold topology can be put to use in existing application areas in ways that differ significantly from the techniques developed for manifold modeling and it can be put to use in new applications that have not been satisfactorily solved by manifold topology. Several applications of non-manifold topology that would be difficult or impossible to implement using a purely manifold geometric modeler are illustrated: automatic formulation of finite element analyses from solid models, automatic generation of machining tool paths for 2½-dimensional pockets, and construction of geometric models using topological constraints. These applications demonstrate how a non-manifold model partitions the entire space in which an object is embedded, preserves elements of the model that would be discarded by conventional schemes, and permits the implementation of a common merge operation. All three applications have been implemented using a two dimensional non-manifold (non-1-manifold) geometric modeler.

scholarly journals Intersections With Validated Error Bounds for Building Interval Solid Models

2005 ◽  
Author(s):  
Harish Mukundan ◽  
Kwang Hee Ko ◽  
Nicholas M. Patrikalakis
Keyword(s):  
Interval Arithmetic ◽  
Error Control ◽  
Model Space ◽  
Critical Issue ◽  
Boundary Representation ◽  
Solid Model ◽  
Efficient Computation ◽  
Solid Models ◽  
Bounding Surfaces ◽  
Marching Method

Interval arithmetic has been considered as a step forward to counter numerical robustness problem in geometric and solid modeling. The interval arithmetic boundary representation (B-rep) scheme was developed to tackle this problem. In constructing an interval B-rep solid, robust and efficient computation of intersections between the bounding surfaces of the solid is a critical issue. To address this problem, a marching method based on a validated interval ordinary differential equation (ODE) solver was proposed, motivated by its potential for the interval B-rep model construction. In this paper, we concentrate on the issue of error control in model space using the validated ODE solver, and further explain that the validated ODE solver can be used in the construction of an interval B-rep solid model using such an error control.

DOMAIN DELAUNAY TETRAHEDRIZATION OF SOLID MODELS

1991 ◽  
Vol 01 (03) ◽  
pp. 299-325 ◽  
Author(s):  
NICKOLAS S. SAPIDIS ◽  
RENATO PERUCCHIO
Keyword(s):  
Delaunay Triangulation ◽  
Boundary Representation ◽  
Solid Model ◽  
Neighborhood Information ◽  
Solid Models

An algorithm is presented for constructing a topologically and geometrically valid Domain Delaunay Tetrahedrization (DDT) of an arbitrarily shaped solid model with quadric curved faces (including objects with holes and nonmanifold objects). The algorithm operates on the boundary representation (B-rep) of the solid, and makes extensive use of properties of the Delaunay triangulation. This algorithm also includes a mechanism for transferring neighborhood information from the solid model to the elements of the tetrahedral model. Neighborhood information is used for identifying tetrahedra to be included in the DDT, and — in combination with geometric criteria — for ensuring that the DDT approximates satisfactorily the curved faces of the solid.

Sign in / Sign up

Export Citation Format

Share Document