• 한국CDE학회논문집
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• 제15권3호
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• pp.243-252
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• 2010

This paper describes a new practical simplification method for feature-based solid models. In this approach, a solid model created using feature modeling operations is first simplified by the suppression of detailed features, and then, if necessary, the model is converted to a surface model to facilitate its modification. Finally, the simplified surface model is delivered to analysis packages. The algorithm was implemented based on CATIA V.5 and applied to mid-surface generation of plastic parts for structural analysis to prove the validity and usefulness.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.828-831
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• 2005

In feature-based multi-resolution modeling, the features are rearranged according to a criterion for the levels of detail (LOD) of multi-resolution models. In this paper, two different LOD criteria are investigated and discussed. The one is the volumes of subtractive features, together with the precedence of additive features over subtractive features. The other is the volumes of features, regardless of whether the feature types are subtractive or additive. In addition, the algorithms to define and extract the LOD models based on the criteria are also described. The criterion of the volumes of features can be used for a wide range of applications in CAD and CAE in virtue of its generality.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.2121-2124
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• 2008

The total length of Korean railway network is about 3,300km. Since it is of great scale in system view point, the systemization of GIS-based information system requires so much cost and time. One of the difficulties is due to the fact that GIS-based information system requires the feature database for GIS, which is generally built manually from many as-built drawing files. In order to build-up the feature database for GIS with ease, this study suggests the automatic data conversion from electronic drawings to make feature database for GIS. The proposed method can be applied to build large-scale railway facility management system at lower cost.

• 한국정보통신학회논문지
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• 제13권11호
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• pp.2335-2340
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• 2009

본 논문은 레퍼런스(reference) 데이터 그룹을 효율적으로 생성하고 활용한 마커리스 증강현실(Markerless Augmented Reality)의 구현 방법을 제안한다. 카메라 설정과 레퍼런스 데이터 그룹 생성, 트래킹 (tracking) 부분으로 되어 있다. 효율적인 레퍼런스 데이터 그룹을 생성하기 위해서는 CAD모델과 같은 3D모델을 필요하며, 다양한 관점에서 본 레퍼런스 데이터 그룹을 생성해야 한다. 모델에 대한 영상에서 특징점들을 추출하고, 광선 추적법을 이용하여 그 특징점에 대응하는 3D좌표를 추출하여, 모델의 특징점들에 대한 2D/3D 대응접의 레퍼런스 데이터 그룹이 구성된다. 트래킹 할 때 현재 프레임영상에서 특징점 들이 가장 많이 매칭되는 레퍼런스 데이터와 그 주위의 모델 데이터만을 이용하기 때문에 빠르게 트래킹할 수 있다.

• Journal of Mechanical Science and Technology
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• 제18권8호
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• pp.1349-1357
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• 2004

Computer-Aided Inspection Planning (CAIP) is the integration bridge between CAD/CAM and Computer Aided Inspection (CAI). A CAIP system for On-Machine Measurement (OMM) is proposed to inspect the complicated mechanical parts efficiently during machining or after machining. The inspection planning consists of Global Inspection Planning (GIP) and Local Inspection Planning (LIP). In the GIP, the system creates the optimal inspection sequence of the features in a part by analyzing the various feature information such as the relationship of the features, Probe Approach Directions (PAD), etc. Feature groups are formed for effective planning, and special feature groups are determined for sequencing. The integrated process and inspection plan is generated based on the sequences of the feature groups and the features in a feature group. A series of heuristic rules are developed to accomplish it. In the LIP of Part II, the system generates inspection parameters. The integrated inspection planning is able to determine optimum manufacturing sequence for inspection and machining processes. Finally, the results are simulated and analyzed to verify the effectiveness of the proposed CAIP.

• 대한기계학회논문집
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• 제17권1호
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• pp.38-45
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• 1993

본 연구에서는 선반작업에서의 피삭체의 형상을 특징형상(feature)단위로 정 의하였고, 이 특징형상을 이용하여 형상정의를 수행한 후 가공순서 및 가공조건을 대 화형식으로 입력하면 공구위치 데이터(CL data)를 자동으로 산출하고 이를 기계제어데 이터(MC data)로 변화시켜 주는 NC선반가공 프로그래밍시스템 FeaTURN (Feature-based TURNing system)을 개발하였다.

• 한국CDE학회논문집
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• 제5권2호
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• pp.103-112
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• 2000

CAD databases are the core element to the management of product information. A key to the successful use of the databases is a rational method of query to and retrieval from the databases. Although it is parts geometry that users eager to retrieve from the CAD databases, no system yet supports geometry-based query. This paper aims at developing a new method of assessing geometric similarity which can serve as the basis of geometric query for CAD database. The proposed method uses ASVP (Alternating Sums of Volumes with Partitioning) decomposition that is a volumetric representation of a part obtained from its boundary representation. A measure of geometric similarity between two solid models is defined on their ASVP tree representations. The measure can take into account overall shapes of parte, shapes of features and their locations. Several properties that a similarity measure needs to satisfy are discussed. The geometric query developed in this paper can be used in a wide range of applications using CAD databases, which include similarity-based design retrieval, variant process planning, and components selection from part library. An experiment has been carried out to demonstrate the effectiveness of the method, and the results are presented.

• Journal of Computational Design and Engineering
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• 제1권1호
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• pp.48-54
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• 2014

In this paper, the authors propose a system for assisting mold designers of plastic parts. With a CAD model of a part, the system automatically determines the optimal ejecting direction of the part with minimum undercuts. Since plastic parts are generally very thin, many rib features are placed on the inner side of the part to give sufficient structural strength. Our system extracts the rib features from the CAD model of the part, and determines the possible ejecting directions based on the geometric properties of the features. The system then selects the optimal direction with minimum undercuts. Possible ejecting directions are represented as discrete points on a Gauss map. Our new point distribution method for the Gauss map is based on the concept of the architectural geodesic dome. A hierarchical structure is also introduced in the point distribution, with a higher level "rough" Gauss map with rather sparse point distribution and another lower level "fine" Gauss map with much denser point distribution. A system is implemented and computational experiments are performed. Our system requires less than 10 seconds to determine the optimal ejecting direction of a CAD model with more than 1 million polygons.

• 패션정보와 기술
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• 제4권
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• pp.8-17
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• 2007

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.613-617
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• 1990

This paper presents a method of calculating the position and orientation of a polyhedron arbitrarily placed in 3-D space using two cameras. We use key feature of the object and CAD data to solve the correspondence problem between two cameras' images.