• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.869-872
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• 2003

This paper presents a geometric machining simulation algorithm to enhance the reliability and user-friendliness of a comprehensive computer aided process planning (CAPP) system by verifying generated NC data. In order to represent the complex machining geometry with high accuracy, the proposed algorithm is developed based on a boundary representative (B-rep) solid modelling kernel. Solid models are used to represent the part geometry. tool swept volume and material removal volume by Boolean unite and subtract operations. By integrating a machining simulation procedure into the CAPP system, the systematic analysis of the tool path can be implemented synthetically. To demonstrate and check the validity of suggested system, a simple example of simulation is represented and the result is discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.670-674
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• 1996

In automated search of a design database to support mechanical design, it is necessaryto recognize a shape pattern which represents a design object. This paper introduces the concept of a surface relation graph (SRG) for recognizing shape patterns from a 3D boundary representation scheme of a solid model(a B-rep model). In SRG, the nodes and arcs correspond to the faces and edges shared by two adjacent faces, respectively. An attribute assigned to an arc is given by an integer which discriminates the relationship between two adjacent faces. The + sign of the integer represents the geometric convexity of the solid, and the -sign the concivity at the shared edge. The input shape is recognized by comparison with the predefined features which are subgraphs of the SRG. A hierarchyof the database for upporting the design is presented. A search for the design database is also discussed. The usefulness of this method is illustrated by some application results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1626-1629
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• 2003

The study is expressed on the web browser using virtual reality of developer manufacturing process and method or manufactured goods conviction for designer and developer with visualized model. This study purpose of basic feature with VRML file and Java and VRML with AWT to get WC code was presented. The study process is equal to the real thing modeling on using Pro/Engineer and exports on the VRML1.0. The condition converts VRML1.0 to VRML2.0 on the CROSS ROADS. And then Cosmo World is coding and manufacturing simulation is expressed on the Cosmo Player.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1991.10a
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• pp.97-115
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• 1991

본 시스템은 주어진 건축 부지위에 최대 건축 가능 공간을 산정한다. 한국 건축법규와 건축조례를 검토하여 가능공간을 산정하며 입력 데이타로는 부지 및 도로의 도형정보 및 부지의 위치정보등을 사용한다. 본 시스템은 일반적인 CAD S/W와 달리 Non-geometric 데이터를 많이 포함하여 데이터 구조 부분이 타 시스템과 많은 차이가 있으므로, 그에 따른 알고리즘을 자체 개발 적용하였다. 본 시스템은 건축 법규 추론 시스템의 결과에 따라 건축 가능 공간을 솔리드 모델로 생성한다. 이를 위해 평면만을 가지는 경계 표현법(B-Rep)솔리드 모델링 기능이 사용되었으며 생성되는 솔리드 모델은 Half-Edge데이터 구조로 저장되며 물성치 계산 기능, 은선제거기능, 음영처리기능들이 개발되었다. 적용시 각 단계를 시각화하고 출력하여 지금까지의 수작업을 배제하고 정확한 결과를 얻게 하여 설계시간을 최소화하고 건축주에게 만족한 결과를 얻게 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.774-778
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• 1996

Developed in this research is a surface modeling kernel for various CAD/CAM applications. Its internal surface representations are rational parametric polynomials, which are generalizations of nonrational Bezier, Ferguson, Coons and NURBS surface, and are very fast in evaluation. The kernel is designed under the OOP concepts and coded in C++ on PCs. The present implementation of the kernel supports surface construction methods, such as point data interpolation, skinning, sweeping and blending. It also has NURBS conversion routines and offers the IGES and ZES format for geometric information exchange. It includes some geometric processing routines, such as surface/surface intersection, curve/surface intersection, curve projection and so forth. We are continuing to work with the kernel and eventually develop a B-Rep based solid modeler.

• International Journal of CAD/CAM
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• v.9 no.1
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• pp.17-24
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• 2010

For several years, researchers have focused on improving the integration of the CAD, CAM and Analysis through a better communication between the various analysis tools. This tendency to integrate the CAD/Analysis and automation of the corresponding processes requires data sharing between the various tasks using an integrated product model. We are interested in this research orientation to CAD/CAM/Analysis integration by rebuilding the CAD model (BREP), starting from the Analysis results (deformed mesh). Because this problem is complex, it requires to be split into several complementary parts. This paper presents an original interoperability process between the CAD and CAE. This approach is based on a new technique of rebuilding the CAD surface model (Nurbs, Bezier, etc.) starting from triangulation (meshed surface) as a main step of the BREP solid model. In our work, the advantages of this approach are identified using a centrifugal pump example.

• 한국IT서비스학회:학술대회논문집
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• 2003.05a
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• pp.623-628
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• 2003

제품의 개발 및 생산 과정에는 설계, 해석, 가공, 검사 등의 많은 부문이 서로 밀접하게 연계되어 있고 각 부문 간에는 각기 서로 다른 형태의 정보를 필요로 하기 때문에 이들의 유기적인 통합을 위해서는 각각의 응용 분야에서 요구되는 다양한 정보가 효과적으로 제공될 필요가 있다. 본 연구에서는 특징형상을 이용하여 설계 기능과 다른 응용 부분을 유기적으로 연계할 수 있는 알고리즘을 제시한다. ISO에서 진행 중인 STEP의 Form Feature을 기준으로 일반적인 분류를 하고 이를 기초로 특징형상을 인식하고자 하였다. 이를 위해 B-Rep 데이터로부터 Face-Edge Graph를 구성하고 다중 절점(Cut Node)을 인식하였으며, 본 연구를 바탕으로 하여 향후 몇 가지 단점을 보완하고 대상 영역을 확대시켜 감으로써 Computer-aided Design 시스템으로부터 얻어지는 3차원 형상 데이터로부터 Computer-aided Process Plan을 위해 필요한 특징형상을 컴퓨터에 의해 자동으로 추출하기 위한 발판을 구축할 수 있을 것이다.

• Proceedings of the Safety Management and Science Conference
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• 2006.11a
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• pp.239-254
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• 2006

In mold structure machining, tool interference is a phenomenon which results from a collision between a blade of tool and a workpiece. Also tool collision is a phenomenon which results from a collision of holder with the object to be machined. These phenomena not only cause damages to mold and tool but also increase machining time and cost. To detect a collision of a tool to mold structure, first of all, the mold structure and a tool must be defined with famous geometric models such CSG, B-rep, and Voxel. A tool is defined as a combination of the blade, the shank, and the holder. This thesis reviews various collision detection algorithms using z-map and computer 3D graphic collision detection algorithms for the tool in machining a mold structure.

• Korean Journal of Computational Design and Engineering
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• v.10 no.6
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• pp.392-401
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• 2005

2D CAD is being replaced by 3D CAD to improve efficiency of product design and manufacturing. Therefore, converting legacy 2D drawings into 3D solid models is required. CSG based approaches construct solid models from orthographic views more efficiently than traditional B-rep based approaches. A major limitation of CSG based approaches has been the limited domain of objects that can be handled. This paper aims at extending the capabilities of CSG based approaches by proposing hint-based recognition of interacting solids of revolution which can handle interacting solids of revolution as well as isolated solids of revolution.

• Korean Journal of Computational Design and Engineering
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• v.22 no.1
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• pp.28-36
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• 2017

Sharing of CAD data plays a key role in the PLM and a lightweight model is widely used for visualizing and sharing a large data. The lightweight model is mainly composed of triangular elements to minimize file size. There is no problem at all to visually confirm the shape based on these triangular elements but there is a limit to numerically calculate the exact position on the curve or surface. In this paper, a boundary curve generation method using triangular elements is proposed to increase the utilization of lightweight models. After matching connectivity of triangular elements, boundary element edges are extracted. Boundary curves are generated by connecting of these boundary element edges. This proposed method has been tested on several models to demonstrate the feasibility.