Instantiation and Manipulation of User-Defined Freeform Features

2008 ◽  
Author(s):  
Thomas R. Langerak
Keyword(s):  
Design Process ◽  
Current Literature ◽  
Design Features ◽  
Shape Model ◽  
Target Shape ◽  
General Methodology ◽  
Feature Based ◽  
Definition Of ◽  
High Level ◽  
Feature Based Design

One of the sub-topics of CAD research is the topic of feature-based design. Features are characteristic parts of a shape to which functional or parameter information can be attached. By using features in a design process, high-level interrogation and editing of a shape model is enabled. It is widely accepted that feature-based design methods should be able to handle user-defined features. Much work has been done on the definition of features and the management of feature definitions, but very little work has been done on the instantiation of these features on a target shape, especially in the domain of freeform shape. This paper discusses the current literature on freeform feature-based design and identifies the issues that play a role in the instantiation and manipulation of freeform features on target shapes. Also, a general methodology is proposed for the instantiation and manipulation of freeform features. Finally, an implementation of the proposed methods and some application examples are given.

Purely Declarative Feature-Based Design With Feature Type Property Maintenance

2004 ◽  
Author(s):  
Dhaval Lokagariwar ◽  
Bernhard Bettig
Keyword(s):  
Design Process ◽  
Research Work ◽  
Building Blocks ◽  
Feature Representation ◽  
Software Systems ◽  
Design Environment ◽  
Design Features ◽  
Planning Algorithm ◽  
Feature Based ◽  
Feature Based Design

Commercial feature-based design systems are based on describing the design model in some form of sequential representation of primitive shapes and operations called features. In these systems, the overall design process, the behavior of building blocks and the characteristics of the final model, are governed by the construction sequence. These systems do not check for the conformity of the final shape with the actual design intent of features, and allow their design and engineering intent to be altered during the design process. The research work presented here describes a new design methodology and feature representation for facilitating a design environment that is independent of any construction order or constraint-based dependencies and provides a mechanism for maintaining design and engineering intent of the design features. The methodology works by dynamically evaluating the features using a planning algorithm such that the validity of each feature is maintained. These are intended to serve as a generic template that can be used to design and develop specific design features and CAD software systems.

SINFONIA: An Open Feature-Based Design Module

1994 ◽  
Author(s):  
J. Ovtcharova ◽  
S. Haßinger ◽  
A. S. Vieira ◽  
U. Jasnoch ◽  
J. Rix
Keyword(s):  
Shape Representation ◽  
Design Feature ◽  
Modular Architecture ◽  
Design Environment ◽  
Design Features ◽  
Cad System ◽  
Feature Based ◽  
Definition Of ◽  
Feature Based Design ◽  
Solid Modeler

Abstract Sinfonia is a module for feature-based design which is configurable to users and applications within diverse CAD environments, particularly in the area of mechanical engineering. Sinfonia has an open and modular architecture that allows to modify and extend existing functionalities, and to integrate new modeling facilities and application tasks. This module enables the users to work with standard pre-defined design features delivered with the module, or to define dynamically their own specific design features during the design session. Furthermore, Sinfonia allows the interactive definition of constraints concerning the product semantics. Definition and administration of constraints in feature-based models provided by a consistency manager is supported to reach semantical correctness of the part models. The main modules of Sinfonia are the Feature Modeler and the Design Feature Manager. The Feature Modeler is responsible for the instantiation of features and the creation of the feature-based model. The Design Feature Manager allows feature data and design processes to be managed in a uniform way. The CAD system environment in which Sinfonia is integrated consists of the following modules: the User Interface System and the Application modules (offering tools for interaction of the user with application specific part models and for communication with external systems and applications, such as NC modules, etc.), the Solid Modeler (responsible for creating the shape representation of the feature-based model), the Consistency Manager (providing services to handle all kinds of different constraints within the design environment) and the Product Database which includes all services for storing and retrieving various product data.

Feature-Based Design: 4 Hypotheses for Future CAD Systems

1993 ◽  
Author(s):  
David W. Rosen
Keyword(s):  
Future Research ◽  
Design Activity ◽  
Research Directions ◽  
Research Issues ◽  
Cad Systems ◽  
Feature Representations ◽  
Feature Based ◽  
Computer Based ◽  
Definition Of ◽  
Feature Based Design

Abstract Features are meaningful abstractions of geometry that engineers use to reason about components, products, and processes. For design activity, features are design primitives, serve as the basis for product representations, and can incorporate information relevant to life-cycle activities such as manufacturing. Research on feature-based design has matured to the point that results are being incorporated into commercial CAD systems. The intent here is to classify feature-based design literature to provide a solid historical basis for present research and to identify promising research directions that will affect computer-based design tools within the next few years. Applications of feature-based design and technologies of feature representations are reviewed. Open research issues are identified and put in the context of past and current work. Four hypotheses are proposed as challenges for future research: two on the existence of fundamental sub-feature elements and relationships for features, one that presents a new definition of design features, and one that argues for the successful development of concurrent engineering languages. Evidence for these hypotheses is provided from recent research results and from speculation about the future of feature-based design.

Representing Tolerance and Assembly Information in a Feature-Based Design Environment

1991 ◽  
Author(s):  
Rajneet Sodhi ◽  
Joshua U. Turner
Keyword(s):  
User Interface ◽  
Design Environment ◽  
Assembly Design ◽  
Assembly Features ◽  
Feature Based ◽  
The Creation ◽  
High Level ◽  
Feature Based Design

Abstract This paper describes a strategy for representing tolerance information and assembly information in a feature-based design environment. The concept of designing with features is extended to incorporate the specification of tolerance information. This allows appropriate tolerancing strategies to be provided within the feature definitions themselves. Thus a closer connection is formed between features and the functional intent implicit in their use. The concept of designing with features is also extended to incorporate the specification of assembly information, through the use of assembly features which provide a high-level user interface for the creation and modeling of assemblies, and which handle the identification and creation of mating relations between components. Several examples of component and assembly design using this extended feature-based approach are presented.

Modeling of Feature-Based Design Process

1998 ◽  
Author(s):  
Fei Gao ◽  
Dieter Roller
Keyword(s):  
Design Process ◽  
Data Exchange ◽  
Concurrent Design ◽  
Product Model ◽  
Product Data ◽  
Product Models ◽  
Critical Issues ◽  
Feature Based ◽  
Feature Based Design ◽  
Feature Evolution

Abstract Capturing design process is becoming an important topic of feature-based modeling, as well as in product data exchange, concurrent design, and cooperative design. Three critical issues on the modeling of design process are considered in this paper, namely, feature concepts, feature evolution, and the semantic consistencies of the states of product models. A semantics-based product model is introduced to facilitate the description of both conceptual and detailed models, and to maintain the semantic consistencies of product states. The process is represented by feature states and their evolution records. Feature type variation and prototype-based design are proposed to support feature evolution. A conceptual description of the design process and an example are given.

A Dual Environment for 3D Modeling With User-Defined Freeform Features

2009 ◽  
Vol 9 (2) ◽  
Author(s):  
Thomas R. Langerak ◽  
Joris S. M. Vergeest
Keyword(s):  
3D Modeling ◽  
Computer Aided Design ◽  
Target Surface ◽  
Feature Modeling ◽  
Dynamic Feature ◽  
Design Features ◽  
Computer Aided ◽  
Definition Of ◽  
High Level ◽  
Aided Design

Modeling with freeform features has become the standard in computer-aided design. Features offer a high-level approach to modeling shapes. However, in most commercial modeling packages, only a static set of freeform features is available. A new method for user-driven feature definition is presented, as well as a method to instantiate these user-defined features on a target surface. We propose the concept of a dual environment, in which the definition of a feature is maintained parallel to its instance on a target surface. This dual environment enables dynamic feature modeling, in which the user is able to change the definition of instantiated features on-the-fly.

Unified Feature Definition for Feature Based Design and Feature Based Manufacturing

1995 ◽  
Author(s):  
Reinholt Geelink ◽  
Otto W. Salomons ◽  
Fjodor van Slooten ◽  
Fred J. A. M. van Houten ◽  
Huub J. J. Kals
Keyword(s):  
Feature Recognition ◽  
Design Feature ◽  
Geometric Constraints ◽  
Planning System ◽  
Conceptual Graphs ◽  
Computer Aided Process Planning ◽  
Feature Based ◽  
Definition Of ◽  
Feature Based Design ◽  
Interactive Feature

Abstract In this paper, interactive “constraint based feature definition” is used to drive both feature based design and feature recognition. At present, hardly any feature based CAD or CAPP system does offer adequate facilities to easily define application specific features. Feature definition by means of programming is an error prone and difficult task. The definition of new features has to be performed by domain experts in the fields of design and manufacturing. In general they will not be programming experts. This paper elaborates on interactive feature definition, aiming at facilitating the definition of features by non-programming experts. The interactive feature definition functionality is implemented in a re-design support system called FROOM. It supports feature based design. Feature definition is also used in a Computer Aided Process Planning system, called PART, for the definition of features to be recognized. Conceptual graphs are used as an aid in the definition of features and for the representation of the features. The conceptual graphs are automatically transformed into feature recognition algorithms. Degrees of freedom (DOF) analysis is used for support during feature definition and for solving geometric constraints related to the feature to be defined.

Representing and Recognizing Features in Mechanical Designs

1990 ◽  
Author(s):  
Susan Finger ◽  
Scott A. Safier
Keyword(s):  
Graph Grammars ◽  
Design Environment ◽  
Geometric Models ◽  
Feature Based ◽  
Geometric Representations ◽  
Design Systems ◽  
High Level ◽  
Feature Based Design ◽  
Structural Engineers ◽  
Rough Surface Finish

Abstract When experts view an object, they perceive it in terms of their own expertise. For example, manufacturers see features that affect the processes used to fabricate a part, while structural engineers see sources of stresses and other features that tend to reduce the life of a part. Features can be geometric, such as slots or chamfers; they can be quantitative, such as distances between holes; they can be functional, such as alignment; or they can be qualitative, such as a rough surface finish. Research in feature-based design systems for mechanical designers has been motivated by the realization that geometric models represent the design in greater detail than can be utilized by designers, process planners, assembly planners, or by systems that emulate these activities. Features provide abstractions to facilitate the creation, representation, and analysis of designs. Our goal is to enable designers to compose mechanical designs from high-level features that embody functional and geometric properties. In addition, we want to provide designers with feedback on the manufacturability, assemblability, functionality, cost, etc. of the design as it evolves. To support this process in an intelligent CAD environment requires the integration of geometric models, analysis tools, and synthesis tools so that all aspects of the design can be considered while it is in progress. We are developing a design environment based on a shared representation of the design in which we can extract and reason about features of the design from different perspectives. Our approach is to represent both the design and the features using graph grammars. By representing the features using the same grammar as the design, we can recognize features by parsing a feature against the graph that represents the design. We are exploring grammars for behavior as well as geometry in order to provide a link between behavioral and geometric representations. In this paper, we focus on the representation and recognition of features.

A Framework for Feature Based Part Modeling

1991 ◽  
Author(s):  
Yuh-Min Chen ◽  
R. Allen Miller ◽  
K. Rao Vemuri
Keyword(s):  
Geometric Reasoning ◽  
Geometric Information ◽  
Cad System ◽  
Knowledge Based ◽  
Modeling Environment ◽  
Cad Cam ◽  
Feature Based ◽  
High Level ◽  
Feature Based Design ◽  
Part Modeling

Abstract To increase the capabilities and intelligence of CAD/CAM systems, a feature based modeling environment, integrated with a knowledge based environment, is under development utilizing a commercial CAD system. This environment allows designers to model parts with features, and provides high-level part models to support geometric reasoning in manufacturing assessment and related functions. Two fundamental issues have been considered: (1) What kind of information is required to specify a part and to support reasoning about the part in a wide variety of applications?, and (2) How can the results serve the geometric reasoning needs of the various engineering applications which need geometric information about the part? This paper will discuss the information required for defining net shaped parts (parts to be manufactured by net shape processes), a framework for a feature based modeling environment, the procedures for feature based design, and the construction of high-level (semantic) pan models suitable for geometric reasoning in a knowledge based environment.

Feature Recognition

2009 ◽  
pp. 90-108
Author(s):  
Xun Xu
Keyword(s):  
Feature Recognition ◽  
Geometric Model ◽  
Feature Model ◽  
Design System ◽  
Cad System ◽  
Domain Specific ◽  
Cad Models ◽  
Feature Based ◽  
High Level ◽  
Feature Based Design

Conventional CAD models only provide pure geometry and topology for mechanical designs such as vertices, edges, faces, simple primitives, and the relationship among them. Feature recognition is then required to interpret this low-level part information into high-level and domain-specific features such as machining features. Over the years, CAD has been undergoing fundamental changes toward the direction of feature-based design or design by features. Commercial implementations of FBD technique became available in the late 1980’s. One of the main benefits of adopting feature- based approach is the fact that features can convey and encapsulate designers’ intents in a natural way. In other words, the initial design can be synthesized quickly from the high-level entities and their relations, which a conventional CAD modeller is incapable of doing. However, such a feature-based design system, though capable of generating feature models as its end result, lacks the necessary link to a CAPP system, simply because the design features do not always carry the manufacturing information which is essential for process planning activities. This type of domain-dependent nature has been elaborated on in the previous chapter. In essence, feature recognition has become the first task of a CAPP system. It serves as an automatic and intelligent interpreter to link CAD with CAM, regardless of the CAD output being a pure geometric model or a feature model from a FBD system. To be specific, the goal of feature recognition systems is to bridge the gap between a CAD database and a CAPP system by automatically recognizing features of a part from the data stored in the CAD system, and based on the recognized features, to drive the CAPP system which produces process plans for manufacturing the part. Human interpretation of translating CAD data into technological information required by a CAPP system is thus minimized if not eliminated.

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