• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.3 s.246
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• pp.219-230
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• 2006

Digital CAD models are one of the most important assets the manufacturer holds. The trend toward concurrent engineering and outsourcing in the distributed development and manufacturing environment has elevated the importance of high quality CAD model and its efficient exchange. But designers have spent a great deal of their time repairing CAD model errors. Most of those poor quality models may be due to designer errors caused by poor or incorrect CAD data generation practices. In this paper, we propose a rule-based approach for healing CAD model errors. The proposed approach focuses on the design history data representation from a commercial CAD model, and the procedural method for building knowledge base to heal CAD model. Through the use of rule-based approach, a CAD model healing system can be implemented, and experiments are carried out on automobile part models.

• CDE review
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• v.3 no.2
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• pp.1-4
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• 1997

본 기사에서는 CAD 모델을 공학적 해석이나 제조공정에 사용하는데 있어 문제가 되고 있는 솔리드 모델의 결함에 관한 문제를 다루고자 한다. International TechneGroup사(ITI) 등과 같은 몇몇 회사들은 솔리드 모델의 결함을 발견하는 소프트웨어를 개발하고 있으며, XOX('zocks'라고 발음함)사는 이런 결함을 자동적으로 수정하는 프로그램을 개발하고 있다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.5
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• pp.693-705
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• 2013

Procedural models have the advantage of being easy to edit simply by changing the values of the parameters of their constructional operations. In previous studies, we have introduced an approach for representing procedural 2D CAD models in ISO 10303 and developed ISO 10303-112 for the exchange of procedural 2D CAD models. In this paper, a method for the development of a procedural 2D CAD data translator supporting ISO 10303-112 is suggested. Furthermore, the core techniques applied to the translator are presented. The feasibility of the proposed method was demonstrated through data exchange experiments using a prototype translator.

• Korean Journal of Computational Design and Engineering
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• v.10 no.4
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• pp.262-273
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• 2005

For CAD data users, few things are as frustrating as receiving CAD data that is unusable due to poor data quality. Users waste time trying to get better data, fixing the data, or even rebuilding the data from scratch from paper drawings or other sources. Most related works and commercial tools handle the boundary representation (B-Rep) shape of CAD models. However, we propose a design history?based approach for healing CAD model errors. Because the design history, which covers the features, the history tree, the parameterization data and constraints, reflects the design intent, CAD model errors can be healed by an interdependency analysis of the feature commands or of the parametric data of each feature command, and by the reconstruction of these feature commands through the rule-based reasoning of an expert system. Unlike other B Rep correction methods, our method automatically heals parametric feature models without translating them to a B-Rep shape, and it also preserves engineering information.

• Korean Journal of Computational Design and Engineering
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• v.16 no.3
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• pp.178-186
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• 2011

Static CAD models are the CAD models that do not have feature information and modeling history. These static models are generated by translating CAD models in a specific CAD system into neutral formats such as STEP and IGES. When a CAD model is translated into a neutral format, its precious feature information such as feature parameters and modeling history is lost. Once the feature information is lost, the advantage of feature based modeling is not valid any longer, and modification for the model is purely dependent on geometric and topological manipulations. However, the capabilities of the existing methods to modify static CAD models are limited, Direct modification methods such as tweaking can only handle the modifications that do not involve topological changes. There was also an approach to modify static CAD model by using volume decomposition. However, this approach was also limited to modifications of protrusion features. To address this problem, we extend the volume decomposition approach to handle not only protrusion features but also depression features in a static CAD model. This method first generates the model that contains the volume of depression feature using the bounding box of a static CAD model. The difference between the model and the bounding box is selectively decomposed into so called the feature volume and the base volume. A modification of depression feature is achieved by manipulating the feature volume of the static CAD model.

• Broadcasting and Media Magazine
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• v.27 no.3
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• pp.67-78
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• 2022

제조업과 같은 산업체에서는 현장을 이해하고 문서를 확인하는 과정에서 시간, 비용이 많이 소요되기 때문에 해석하기 용이한 3차원 형태의 데이터로 미리 제작하고 온라인으로 모델을 공유하고 수정하는 것은 작업 효율을 향상시킬 수 있다. 작업물을 3D 객체 형태로 분석하거나 수정 보완을 위한 가상 목업(mock-up)으로 활용할 경우, 3D 모델링을 빠르고 정확하게 생성하는 기술에 대한 연구가 필요하다. 본 논문에서는 2D CAD 이미지를 분석하여 도형 형태와 수치 정보를 각각 인식하고 3D 객체를 자동 생성하는 방법의 설계를 제안한다. 제안한 방식을 통해서 2D 이미지 파일의 별도 변환 없이 3D 객체로 자동 생성할 수 있다. 빠르게 자동 생성된 3D 객체는 XR 등의 다양한 플랫폼에서 정확하고 세밀한 형태를 가상 공간에서 공유할 수 있어 작업자 간 협업 효율성을 높일 수 있다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.583-587
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• 1996

형상 모델링은 CAD/CAM이나 다른 공학 응용 시스템을 구성하는 데에 있어서 중요한 기술 중에 하나이다. 그리고, 이러한 형상 모델링이 효율적으로 구현되기 위해선, 보다 효율적인 형상 모델을 구현할 수 있어야 한다.(중략)

• Journal of the Korea Institute of Building Construction
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• v.16 no.2
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• pp.169-175
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• 2016

A survey of small-size contractors in Jeju was conducted to investigate college graduate's CAD (computer aided design) competence. Most of small-size contractors use CAD softwares to review and update drawings submitted from an architect. This research analyzed the curriculum of the architectural engineering in several national universities. The CAD classes have 4 or 6 hours per week and use AutoCAD primarily. This research proposes that a CAD class needs at least 6 hours per week, 2D drawing is the main theme in the curriculum, and exercises to make 3D models are also included in the CAD class. The improved methods, Internet cafe and real time feedbacks using a smartphone, to evaluate the reports and exercise results are necessary.

• Korean Journal of Computational Design and Engineering
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• v.13 no.2
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• pp.131-138
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• 2008

With the advancements of the Internet and CAD data translation techniques, more CAD models are transferred from a CAD system to another through the network and interoperability is getting a common word in the CAD industry. However, when a CAD model is translated for an incompatible system into a neutral format such as STEP or IGES, its precious feature information is lost. When this feature information is lost, the advantage of feature based modeling is not valid any longer, and modification for the model is purely dependent on geometric and topological manipulations. However, the capabilities of the existing methods to modify these feature-independent models are limited as the modification involves a topological change in the model. To address this issue, we present a volumetric method to modify the solid models in neutral format. First, this method selectively decomposes the solid model to separate the portion of interest called feature volume. Next, the designer modifies the feature volume without concerning a topological change. Finally, the feature volume is united with the original solid model to complete the modification process. The results of test cases are presented to attest the usefulness of the proposed method.

• Journal of the Korea Computer Industry Society
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• v.10 no.1
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• pp.1-12
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• 2009

In this thesis, founded on those considerings, plan the formula of media data for the information of drawing for the production of steel plate by establishing the concept of relational data model, plan the surroundings for query for the interface of user, and introduce the process materialized actually in detail as use the management system of drawing.