Verification of Boundary Representations of Solid Models

1994 ◽  
Vol 116 (2) ◽  
pp. 666-668
Author(s):  
A. G. Jablokow ◽  
J. J. Uicker ◽  
D. A. Turcic
Keyword(s):  
Design Automation ◽  
Solid Modeling ◽  
Solid Model ◽  
Object Model ◽  
Application Program ◽  
Solid Models ◽  
Verification Algorithms ◽  
Boundary Representations ◽  
Object Models

Verification of polyhedral boundary representations (B-reps) of solid models through the use of an algorithm is addressed here. The validity conditions for B-rep models are presented in a format which leads directly to a set of verification algorithms. The validity verification algorithms are intended for design automation through execution after each solid modeling operation, after localized geometry modification, on imported object model databases, prior to storage of object models, or prior to execution of an application program on the solid model.

Topological and Geometric Consistency in Boundary Representations of Solid Models of Mechanical Components

1993 ◽  
Vol 115 (4) ◽  
pp. 762-769 ◽  
Author(s):  
A. G. Jablokow ◽  
J. J. Uicker ◽  
D. A. Turcic
Keyword(s):  
Data Exchange ◽  
Solid Modeling ◽  
Boundary Representation ◽  
Solid Model ◽  
Design Data ◽  
Solid Models ◽  
Geometric Consistency ◽  
Boundary Representations ◽  
Mechanical Components ◽  
Manufacturing Applications

This paper describes a method of verifying the consistency (i.e., agreement) between the topology and geometry of boundary representation (B-rep) solid models of mechanical components. This verification is well-suited for implementation as an algorithm and has been implemented as such in a polyhedral boundary representation solid modeling system (Jablokow, 1989). This technique and algorithm is important in the design of mechanical components for design documentation, integration with analysis and manufacturing applications, and design data exchange between solid modeling systems. Information regarding boundary representations has typically divided into the geometry and topology. It is important that the two are consistent for a valid solid model. In this work the genus of a solid model of an object is calculated topologically and geometrically and then compared to verify the consistency of the solid model. The genus of an object gives insight as to the geometric complexity of the object. This is equivalent to verifying the Gauss-Bonnet Theorem for the model, and is discussed in the paper.

Topological and Geometric Consistency in Boundary Representations of Solid Models

1990 ◽  
Author(s):  
Andrei G. Jablokow ◽  
John J. Uicker ◽  
David A. Turcic
Keyword(s):  
Solid Modeling ◽  
Boundary Representation ◽  
Solid Model ◽  
Geometric Complexity ◽  
And Topology ◽  
Solid Models ◽  
Geometric Consistency ◽  
Boundary Representations ◽  
Bonnet Theorem

Abstract This paper describes a method of verifying the consistency between the topology and geometry of boundary representation (B-rep) of solid models. This verification is well suited for implementation as an algorithm and has been implemented as such in a polyhedral boundary representation solid modeling system (Jablokow 1989). Information regarding boundary representations is typically divided into the geometry and topology. It is important that the two are consistent for a valid solid model. In this work the genus of an object is calculated topologically and geometrically and then compared to verify the consistency of the solid model. The genus of an object gives insight as to the geometric complexity of the object. This is equivalent to verifying the Gauss-Bonnet Theorem for the model, and is discussed in the paper.

Solid Modeling of In-Process Workpiece Geometry for Hole Milling

2012 ◽  
Author(s):  
Jue Wang ◽  
Derek Yip-Hoi
Keyword(s):  
Cutting Forces ◽  
Tool Path ◽  
Solid Modeling ◽  
Solid Model ◽  
Virtual Machining ◽  
Solid Models ◽  
Milling Operation ◽  
Swept Volumes ◽  
Swept Volume ◽  
Physics Based Simulation

Capturing the in-process workpiece geometry generated during machining is an important part of tool path verification and increasingly the physics-based simulation of cutting forces used in Virtual Machining. Swept volume generation is a key supporting methodology that is necessary for generating these in-process states. Hole milling is representative of one class of milling operation where the swept volume is continuously intersecting. Due to this it is impossible to decompose the tool path into non-intersecting regions which is typically the approach used in solid model based swept volume generation. In this paper an approach to generating NURBS based solid models for self-intersecting swept volumes generated during hole milling is presented. NURB surfaces are generated that compactly represent the surfaces of the swept volume. This utilizes the geometry of the helical curve as opposed to a linearly interpolated tool path that is used for more generic approaches to generating swept volumes. Examples applying the approach to various types of cutter geometries used in milling are presented.

Reconstruction of B-rep Solid Models From Finite Element Meshes for Design Automation

1993 ◽  
Author(s):  
Andrei G. Jablokow ◽  
Isaac Abraham
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Design Automation ◽  
Boundary Representation ◽  
Finite Element Mesh ◽  
Solid Model ◽  
Element Analysis ◽  
Element Mesh ◽  
Solid Models ◽  
Finite Element Meshes

Abstract This paper presents the integration of Finite Element (FE) techniques with B-rep solid modeling. Algorithms for constructing B-rep solid models from a finite element meshes are presented. The finite element mesh data, which consists of node coordinates and connectivity information, is read in from any standard finite element analysis package (currently SDRC IDEAS and MSC/XL) and then processed to construct a polyhedral non-manifold B-rep solid model of the geometry. Since the finite element mesh of a solid object is essentially a non-manifold object, existing geometric modeling data structures based on two-manifold topologies cannot represent it directly. In this work the non-manifold radial-edge data structure is used for the internal representation of the finite element mesh. The mesh is then processed using non-manifold topology operators to eliminate internal nodes and elements to arrive at the solid model that is a polyhedral boundary representation. The results are useful for design automation through the integration of CAD with finite element analysis, shape optimization, as well as the manufacturing of geometry stored as a finite element mesh.

Geometric Assistance for the Construction of Non-Polyhedral Solids From Orthographic Views

1997 ◽  
Author(s):  
Carol Hubbard ◽  
Yong Se Kim
Keyword(s):  
Computer Graphics ◽  
Solid Model ◽  
Geometric Framework ◽  
Mechanical Parts ◽  
Interactive Computer Graphics ◽  
Mechanical Part ◽  
Solid Models ◽  
Spherical Surfaces ◽  
Rapid Construction ◽  
Engineering Drawings

Abstract As the extensive use of solid models becomes widespread, it is important to have a mechanism by which existing engineering drawings can be converted into solid models. Therefore, a geometric assistant which can aid in the construction of solid models is beneficial. In this paper, we present key operations for a system called the Assistant for the Rapid Construction of Solids (ARCS), that provides this assistance given a set of two orthographic views. ARCS is based on the Visual Reasoning Tutor (VRT), a system we developed that provides users with the geometric framework to build polyhedral solids from their orthographic views. However, the geometric domain of ARCS encompasses non-polyhedral solids with cylindrical and spherical surfaces, such as those found in typical mechanical parts. We have devised the Cylindrical and Spherical Warping operations to create cylindrical and spherical surfaces, which use interactive computer graphics that guide a human user to build non-polyhedral faces of a solid. These operations are then illustrated with an example using ARCS to create the solid model of a typical mechanical part from its orthographic projections.

Destructive Modeling by Volume Decomposition and Its Applications

2003 ◽  
Author(s):  
Yoonhwan Woo ◽  
Sang Hun Lee
Keyword(s):  
Decomposition Method ◽  
Solid Model ◽  
Solid Models ◽  
Volume Decomposition ◽  
Number Of Cells ◽  
Natural Way

Adding simple volumes, which are often called primitives, is a natural way to construct complex solid models. Conversely, cell-based volume decomposition is the existing method to decompose a complex solid model into simpler volumes that are often the primitives used to create the model. One problem of this volume decomposition is that it generates a large number of cells, many of which are unnecessary for the decomposition. In this paper, a volume decomposition method that improves the performance by avoiding generating the unnecessary cells is presented. Some possible applications are also presented to attest the usefulness of this volume decomposition method.

Surface Reconstruction From Triple Dexel Model for Virtual Sculpting

2007 ◽  
Author(s):  
Weihan Zhang ◽  
Ming C. Leu
Keyword(s):  
Differential Equation ◽  
Surface Reconstruction ◽  
Boundary Surface ◽  
Solid Modeling ◽  
Haptic Interface ◽  
Solid Model ◽  
Virtual Sculpting ◽  
Novel Method ◽  
Swept Volume ◽  
Differential Equation Method

This paper presents a novel method for surface reconstruction from triple dexel data for virtual sculpting. A triple dexel based virtual sculpting system is developed to provide the capability of interactive solid modeling with haptic interface. A solid model is converted to triple dexel data, which depicts the intersections of the solid with rays cast in three orthogonal directions, and modified during the virtual sculpting process. The boundary of the tool swept volume is computed based on the Sweep Differential Equation method. Contour generation and combination algorithms convert the triple dexel data to three sets of orthogonal slices of contours. A tiling algorithm then generates the solid’s boundary surface in triangular facets from these contours. Examples are given to demonstrate the ability of the developed method and software to realistically simulate the physical sculpting process and to allow viewing the sculpted models in any directions.

Internet Based Framework to Perform Automated FEA on User Customized Products

2003 ◽  
Author(s):  
Zahed Siddique ◽  
Jiju A. Ninan
Keyword(s):  
Product Family ◽  
Solid Model ◽  
Product Families ◽  
Analysis And Evaluation ◽  
The Past ◽  
Evaluation Of Performance ◽  
Internet Users ◽  
Solid Models ◽  
3D Solid ◽  
Fea Analysis

Designing family of products require analysis and evaluation of performance for the entire product family. In the past, products were mainly mass-produced hence the use of CAD/CAE was restricted to developing and analyzing individual products. Since the products offered using a platform approach include a variety of products built upon a common platform, CAD/CAE tools need to be explored further to assist in customization of products according to the customer needs. In this paper we investigate the development of a Product Family FEA (PFFEA) module that can support FEA analysis of user customized product families members. Customer specifications for family members are gathered using the internet, users are allowed to scale and change configurations of products. These specifications are then used to automatically generate 3D solid models of the product and then perform FEA to determine feasibility of the customer specified product. In this paper, development of the PFFEA module is illustrated using a family of lawn trimmer and edger. The PFFEA module uses Pro/E to generate the solid model and ANSYS as the base FEA software.

scholarly journals My document object model can do more than yours

2013 ◽  
Author(s):  
Alain Couthures
Keyword(s):  
Object Model ◽  
Data Types ◽  
Document Object Model ◽  
Xml Documents ◽  
Object Models ◽  
Xml Technologies ◽  
Sequence Types

Document object models, specifically the browser DOM, were designed to represent HTML and XML documents. Languages such as XPath were designed to access and traverse the DOM of HTML and XML documents. But suppose we wanted to bring the power and convenience of XML technologies like XPath to new data types. Could we extend the DOM to support CSV files? JSON? ZIP files? Yes we can! This paper explores a number of ways in which the DOM can be made to do more. We can loosen restrictions, describe new sequence types, and even define new XPath axes to make the DOM better and more useful.

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.

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