Feature Modeling System Research Articles

Name and Maintain Topological Faces in Rotating and Scanning Features

Features created in rotating and scanning operations are very complex. Naming and identifying their topological faces is an important problem in CAD fields. In this paper, a new method of coding topological faces in rotating and scanning features is proposed. Firstly, contour segments are numbered. Secondly, an angle between contour segment and rotating axis is computed. Thirdly, all topological faces are named based on contour segments’ numbers, rotating axis and other information. When a face splits and several subfaces merge, a method of processing their codes is given. The proposed method is applied to HUST-CAID feature modeling system. Experimental results show that it can name and identify topological faces effectively in operations.

Interdisciplinary Semantic Interactions within a Unified Feature Model for Product Cost Estimation

This paper reports a preliminary investigation on automatic cost estimation with a feature-based semantic model. Cost feature has been defined by the authors as a unique class in the unified feature modelling system to address the characteristics of cost engineering entities, constraints and dependency relations. This paper describes the relations between a cost feature and three engineering sub-models, i.e. machining model, design model and other auxiliary data model by associating tangible and intangible data. Further, semantic relations are investigated in early product design process for dynamic, accurate and visible product cost estimation. This paper also discusses cost engineering related functions, associated data structures, and techniques proposed in details. A case study is used to show cost feature properties and functions. Also they are used to illustrate the interactions with the three engineering sub-models to verify the relations.

Sketch2Jewelry: Semantic feature modeling for sketch-based jewelry design

Sketch-based modeling has attracted considerable attention in recent years. In this paper, we propose a semantic feature modeling system for sketch-based jewelry design, called blue Sketch2Jewelry. The newly devised semantic feature class encodes specific domain knowledge (jewelry design knowledge in this paper) and supplies prolific semantic information. The advantage of using semantic features is to narrow down the searching space in sketch-based feature retrieval and benefits the parameter selection from input sketches for feature instantiation and feature placement. Thus, the inaccuracy and ambiguity problems of freehand sketch inputs are alleviated within Sketch2Jewelry, compared to previous commercial feature-based modeling tools, e.g. SolidWorks, which are limited to fake sketches (i.e. not real freehand inputs). Since semantic features are high-level building blocks, together with sketch inputs, the proposed Sketch2Jewelry system can significantly improve the jewelry design efficiency. In addition, Sketch2Jewelry allows non-experts to sketch a complex jewelry model naturally and efficiently with design-by-feature. Examples are provided to demonstrate its usefulness.

Research and Application of Intelligent CAD Technology in R and D and Management of the Electric Equipment

The paper chooses SolidWorks as the developing platform and Electric Equipment as object, researches into the principle of redevelopment by parameter-driving based on 3D feature modeling system of SolidWorks is introduced. Intelligent-CAD system is developed oriented to Electric Equipment by the parametrization structural design actuation technology, the manufacture characteristic automatic diagnosis and the extraction technology, the manufacture characteristic and the design resources, the design knowledge intelligence matching technique and so on. Through applies this system, we should develop the parametrization model of vise crucial element quickly, should extraction and memory components characteristic information and completion of the design features and design resources, design knowledge matching, and so on. The system should achieve to quickly finish product design, to shorten the development cycle and reduce product development costs.

Manufacturing Feature Modeling System Framework Based on XML and UG Platform

Feature modeling technology is the requirement of Advanced Manufacturing Technology (AMT). It is one of the key technologies of CAD/CAPP/CAM integrated system to build a shared part feature model. A feature modeling system can provide not only the geometry information of a part, but also the processing information of the part, which is needed by the latter CAM system, to realize information share and exchange between CAX systems. In the paper, feature concept, feature classification, model structure and modeling method based on features are introduced. Then, an interactive feature modeling method is presented. According to the requirement of CAPP, the system developed can supply the processing information to generate the corresponding manufacturing feature model that can be output in XML file format for a CAPP system.

Research on Cube-based Boolean Operation in Cellular Semantic Feature Modeling System

Research on Cube-based Boolean Operation in Cellular Semantic Feature Modeling System

Numeric and curve parameters for freeform surface feature models

The success of feature modelling systems depends to a large extent on offering user-friendly ways for specifying and varying feature models. In this paper, several new facilities are introduced for this. Numeric and curve parameters are presented for specification and variation of freeform surface feature models. Several properties of the parameters can be defined, such as the direction of evaluation for a curve parameter. In addition to parameters present in features, other parameters can be added to a feature model, including intersection curves between features. To provide these facilities, a new three-level structure is introduced, which includes a partially evaluated model that can capture new generic model entities, including feature intersection curves. The work has been implemented in a prototype surface feature modelling system with functionality for feature class definition, feature model creation, and advanced feature model variation through the new types of parameters.

A Workbench for Geometric Constraint Solving

AbstractGeometric constraints are used in geometric and feature modeling systems to impose conditions on the shape of a product. To determine whether these conditions are correctly applied to a model, and to compute the final solution in which all conditions are satisfied, a geometric constraint solver is used.Current constraint solvers usually handle only 2D constraints. With the introduction of solvers that support 3D constraints, the interaction and visualization techniques for 2D constraints are no longer sufficient. Also, the feedback provided by the 2D constraint solvers, especially if problems are not well-constrained, is limited and not applicable to 3D modeling environments.In this paper, a workbench is presented that can assist a user in defining geometric constraints in 3D and in creating a valid 3D model. Feedback provided by the solver is presented to the user in several ways that enable him to easily interpret this feedback.

Constraint solving for direct manipulation of features

In current commercial feature modeling systems, support for direct manipulation of features is not commonly available. This is partly due to the strong reliance of such systems on constraints, but also to the lack of speed of current constraint solvers. In this paper, an approach to the optimization of geometric constraint solving for direct manipulation of feature dimensions, orientation, and position is described. Details are provided on how this approach was successfully implemented in the Spiff feature modeling system.

Feature modeling using a grammar representation approach

In intelligent computer-aided design the concept of intelligence is related to that of integration. Using feature-based computer-aided design models is thought to make a complete integration. This paper presents a feature recognition approach based on the use of a feature grammar. Given the complexity of feature recognition in interactions, the basic idea of the approach is to find the latent and logical structure of features in interaction. The approach includes five main phases. The first phase, called regioning, identifies the potential zones for the birth of features. The second phase, called virtual extension, builds links and virtual faces. The third phase, called structuring, transforms the region into a structure compatible with the structure of the features represented by the feature grammar. The fourth phase, called Identification, identifies the features in these zones. The fifth phase, called modeling, represents the model by features. The feature modeling system software is developed based on this approach.

Efficiency of boundary evaluation for a cellular model

Feature modeling systems usually employ a boundary representation (b-rep) to store the shape information on a product. It has, however, been shown that a b-rep has a number of shortcomings, and that a cellular representation can be a valuable alternative. A cellular model stores additional shape information on features, including the feature faces that are not on the boundary of the product. Such information can be profitably used for several purposes. A major operation in every feature modeling system is boundary evaluation, which computes the geometric model of a product, i.e. either the b-rep or the cellular model, from the features that have been specified by the user. Since boundary evaluation has to be executed each time a feature is added, removed or modified, its efficiency is of paramount importance. In this paper, boundary evaluation for a cellular model is described in some detail. Its efficiency is compared to the efficiency of boundary evaluation for a b-rep, on the basis of both complexity analysis and performance measurements for the two types of evaluation. It turns out that boundary evaluation for a cellular model is, in fact, more efficient than for a b-rep, which makes cellular models even more attractive as an alternative to b-reps.

A Collaborative Framework for Integrated Part and Assembly Modeling

An ideal product modeling system should support both part modeling and assembly modeling, instead of just either of them as is the case in most current CAD systems. A good basis for such integration is multiple-view feature modeling, as it allows focusing on different aspects of the product, while at the same time maintaining consistency of all model views. This paper presents a framework that supports synchronous collaborative sessions via Internet, among members of a distributed development team, with such a modeling system. The framework provides facilities for creating a hierarchical product structure, with single and compound components, and meanwhile assigning tasks to team members. The actual design of a single component is supported by a web-client specialized in part design, whereas the specification of assembly relations among components is supported by a web-client specialized in assembly design. All clients make use of the same server, which runs a multiple-view feature modeling system and maintains the complete product model, guaranteeing consistency of the part design and the assembly design views.

A Collaborative Feature Modeling System

Collaborative systems are distributed multiple-user systems that are both concurrent and synchronized. An interesting research challenge is to develop a collaborative modeling system that offers all facilities of advanced modeling systems to its users, while at the same time providing them with the necessary coordination mechanisms that guarantee effective collaboration. To achieve this, a web-based collaborative feature modeling system, webSpiff, has been developed. It has a client-server architecture, with an advanced feature modeling system as a basis for the server, providing feature validation, multiple views and sophisticated visualization facilities. A careful distribution of the functionality between the server and the clients has resulted in a well-balanced system. On the one hand, the server offers all the functionality of the original feature modeling system. On the other hand, all desirable interactive modeling functionality is offered by the clients, ranging from display of feature model images to interactive model specification facilities. The architecture of webSpiff, the distribution of model data, the functionality of the server and the clients, and the communication mechanisms are described. It is shown that a good compromise between interactivity and network load has been achieved, and that indeed advanced feature modeling with a collaborative system is feasible.

Enforcing Model Validity by Automatic Adjustment

In current modeling systems, all dimensions in a model have to be fully specified by the user. It is desirable that systems become more flexible in this respect, i.e. that non-critical dimensions in a model can be declared variant, and that the model can be automatically adjusted to enforce its validity when it is invalid. A method to realize this in feature modeling systems is described. The underlying feature model definition and validation approach are introduced. Validation is done by a collection of constraint solvers. An overview of invalid situations in which automatic model adjustment can be applied is given. The constraint solving scheme and, in particular, the automatic model adjustment strategies for different types of constraints are elaborated. Applications to enforce model validity are given for the areas of design by features, creating a member of a family of products, and feature conversion. These illustrate that automatic model adjustment is a very useful concept.

Semantic feature modelling

Almost all current feature modelling systems are parametric, history-based modelling systems. These systems suffer from a number of shortcomings with regard to the modelling process. In particular, they lack a complete specification of feature semantics, and therefore fail to maintain the meaning of the features during modelling. Also, modelling operations sometimes are hampered by the model history, and occasionally even have ill-defined semantics. In the semantic feature modelling approach presented here, the semantics of features is well defined and maintained during all modelling operations. The result of these operations is independent of the order of feature creation, and is well defined. The specification of feature classes, the structure and functionality of the feature model, in particular the Cellular Model, and the model validity maintenance scheme are described. The advantages and disadvantages of the approach, compared to current feature modelling approaches, are pointed out.

Representation and management of feature information in a cellular model

Many limitations in current feature modelling systems are inherited from the geometric representation they use for the product model. Both a very rigid and a very extensive representation are unsuitable for feature applications, at least if no convenient support is provided to manage the data. This paper describes a cellular representation for feature models that contains all the relevant information to effectively solve a variety of current problems in feature modelling. Much benefit is gained from a coherent integration between shapes of a feature model and cells in the cellular model. Every feature shape has an explicit volumetric representation in terms of cells. Specific subsets of its boundary are also distinguished in terms of cell faces and edges. Feature interactions are maintained in attributes of cells, cell faces and cell edges. Methods for modifying and querying the cellular model are presented, and their application is illustrated for feature validity maintenance, feature interaction management, feature conversion between multiple views, and feature visualization.

Coding and clustering of design and manufacturing features for concurrent design

A feature modeling system using two types of features, design features and manufacturing features, is introduced for modeling these two product life-cycle aspects. Design features, represented as mechanical components and mechanisms, are used for modeling design candidates to satisfy design functions. A design feature coding system is developed based on the analysis of design functions. A fuzzy pattern clustering algorithm is employed to organize the large design feature library into hierarchical feature groups. Required design features are identified using graph-based search. A manufacturing feature is a geometric element to be produced. A manufacturing feature coding system is developed based on the analysis of product geometry and production operations. A group-technology-like approach is introduced to organize components into groups according to their manufacturing feature codes using a fuzzy clustering algorithm. Production operations are optimized by a special optimization module. The two coding systems have been implemented in a feature-based, integrated concurrent design system for generating design candidates and planning production processes.

The potential to exchange feature models with user defined feature libraries

It is widely recognised that feature based modelling techniques can lead to enhanced process integration and have direct impact on Simultaneous Engineering activities. Powerful User Defined Feature capabilities have been shown to be essential to the acceptance of Feature Modelling Systems. However, one major stumbling block remains: currently no standardised method for the exchange of User Defined Feature Models exists. Any integration that has been implemented between differing systems is bespoke and not user definable, hindering the impact of feature modelling technologies. This paper considers the powerful User Defined Feature functionality provided by FeatureM, the feature based solid modeller from straessle. This functionality is compared to current approaches based on EXPRESS for describing Feature Libraries. If a distinction is drawn between the generation of the geometry of a feature and the way a system controls the user interaction with that feature, a method is proposed that would allow the exchange of feature models between systems.

Feature modelling by incremental feature recognition

A novel feature-modelling system which implements a hybrid of feature-based design and feature recognition in a single framework is described. During the design process of a part, the user can modify interactively either the solid model or the feature model of the part while the system keeps the other model 3onsistent with the changed one. This gives the user the freedom of choosing the most convenient means of expressing each required operation. The system is based on a novel feature recognizer that provides incremental feature recognition, which allows changes to a geometric model to be recognized as new or modified features while preserving previously recognized features that remain unchanged in the geometric model. Each recognizable feature type is specified by means of a feature-definition language which facilitates the addition of new feature types into the system.

Introducing blending operations in feature models

AbstractWe describe the implementation of a blending facility in the context of a feature modelling system where solid and feature‐based modelling operations can be utilized in parallel during the design process of a part. The definition of blends can be done in a graphical user interface by selecting edges to be blended. Feature recognition of blends facilitates the definition process of blends. Alternatively, a special feature editor can be used to add blends to the feature model. The particular implementation style chosen gives rise to aflexible and easy‐to‐use modelling tool.