The field of solid modeling has developed a variety of techniques for unambiguous representations of three-dimensional objects. Feature recognition is a sub-discipline of solid modeling that focuses on the design and implementation of algorithms for detecting manufacturing information from solid models produced by computer-aided design (CAD) systems. Examples of this manufacturing information include features such as holes, slots, pockets and other shapes that can be created on modern computer numerically controlled machining systems. Automated feature recognition has been an active research area in solid modeling for many years and is considered to be a critical component for integration of CAD and computer-aided manufacturing. The paper gives an overview of the state-of-the-art in feature recognition research. Rather than giving an exhaustive survey, we focus on the three of the major algorithmic approaches for feature recognition: graph-based algorithms, volumetric decomposition techniques, and hint-based geometric reasoning. For each approach, we present a detailed description of the algorithms being employed along with some assessments of the technology. We conclude by outlining important open research and development issues.

Manufacturing feature recognition from solid models: a status report

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1416&context=mechengfacpub

A scientific foundation of collaborative engineering

This paper presents a methodology for efficiently recognizing both isolated and interacting features in a uniform way. The conventional, graph-based recognition method is combined with hint-based feature recognition to recognize and extract alternative interpretations of interacting features. First all isolated (non-intersecting) features are recognized based on a Manufacturing Face Adjacency Graph. Interacting features are then recognized based on the feature's minimal condition subgraph (MCSG) that is used as a feature hint. Unlike Previous hint-based recognition methods, the MCSGs of all features are defined, generated and completed in a uniform way, independent of the feature type. Hints are defined by an Extended Attributed Adjacency Graph, generated by graph decomposition and completed by adding virtual links, corresponding to entities lost by interactions. An efficient algorithm for generating virtual links is developed. A new classification of feature interactions is also presented.

Automatic recognition of interacting machining features based on minimal condition subgraph

A discourse on geometric feature recognition from CAD models

In the market-place of the 21st century, there is no place for traditional ‘over-the-wall’ communications between design and manufacturing. In order to ‘design it right the very first time’, designers must ensure that their products are both functional and easy to manufacture. Software tools have had some successes in reducing the barriers between design and manufacturing. Manufacturability analysis systems are emerging as one such tool — enabling identification of potential manufacturing problems during the design phase and providing suggestions to designers on how to eliminate them. In this paper, we provide a survey of current state-of-the-art automated manufacturability analysis. We present the historical context in which this area has emerged and outline characteristics to compare and classify various systems. We describe the two dominant approaches to automated manufacturability analysis and overview representative systems based on their application domain. We describe support tools that enhance the effectiveness of manufacturability analysis systems. Finally, we attempt to expose some of the existing research challenges and future directions.

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Automated manufacturability analysis: a survey

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.

Feature modelling by incremental feature recognition

A feature definition language for bridging solids and features

A feature-based modelling system is introduced where the user can create, modify, and instantiate part families. Part family and feature descriptions are coded in a special definition language and can be easily added and modified by the user. Feature geometry definitions are embedded in feature descriptions. When creating a new part family, a stored design history can be utilized for generating the geometry definition of the family. The feature structure of the family can be created on the basis of a recognized instance. The part description can be further edited using a frame editor.

Feature-based Modelling of Families of Machined Parts

The techniques of constraint propagation have recently been successfully applied to feature-based design. Because of their speed, constraint propagation methods allow incremental design and rapid local modifications of the part. However, cyclic constraints cause serious problems to current constraint propagation algorithms. Variational geometric design systems can, in principle, manage these cases. Unfortunately, this typically requires complete re-evaluation of the underlying set of constraint equations, making the method unsuitable for interactive use. The proposed system aims to localize the problem of constraint solving and maintenance. The constraint graph of the part or assembly is divided into several independent partial graphs, subsystems. Afterwards, each subsystem is handled separately using a selected constraint solving technique for the subsystem.

Incremental constraint modelling in a feature modelling system

A rounding facility is described that can perform some of the most common edge and corner smoothings encountered in the design of mechanical parts. The roundings are based on the rolling ball principle and the underlying geometric modeller uses boundary representation. The surfaces used are natural quadrics and tori.

Timo Laakko

Papers

Feature modelling by incremental feature recognition

A feature definition language for bridging solids and features

Feature-based Modelling of Families of Machined Parts

Incremental constraint modelling in a feature modelling system

Rounding facility for solid modelling of mechanical parts