• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.841-845
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• 1996

Reverse engineering enables a fast creation of CAD model from an existing part without any technical drawing or digital data. This method of data acquisition is necessary in several industrial applications when the modification of an existing product design has to be performed and verified afterwards. In this paper, the surface of an existing ship propeller was measured by a tactile measuring system and the acquired point data of the surface were used for modeling of a solid model in CAD system. By using LOM and casting processes, an aluminum propeller for functional test was manufactured and then its accuracy was measured by a laser scanner and compared with the origin릴 CAD data. As the results show, the use of LOM as a rapid prototyping process and casting as a secondary process delivers a functional prototype propeller which can be used for test purposes.

• 한국정밀공학회지
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• 제16권4호통권97호
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• pp.102-109
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• 1999

Reverse engineering is a technique that helps designers to quickly generate computer interpretable data from existing physical objects. It can be used for generating CAD data from a mechanical part of high precision, or generating computer animation characters from physical mock-ups. We developed a low precision reverse engineering system that is composed of surface/solid generation software and a contact type commercial 3D digitizer. A unique point sampling procedure has been devised to easily form solid topology from the sampled data. It was also shown that STL data for rapid prototyping was successfully generated from the solid.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.641-642
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• 2015

Unlike for other building processes, BIM for earthwork does not need a large variety of 3D model shapes; however, it requires a 3D model that can efficiently reflect the changing features of the ground shape and provide soil type-dependent workload calculation and information on equipment for optimal management. Objects for earthwork have not yet been defined because the current BIM system does not provide them. The BIM technology commonly applied in the manufacturing center uses real-object data obtained through 3D scanning to generate 3D parametric solid models. 3D scanning, which is used when there are no existing 3D models, has the advantage of being able to rapidly generate parametric solid models. In this study, A method to generate 3D models for earthwork operations using reverse engineering is suggested. 3D scanning is used to create a point cloud of a construction site and the point cloud data are used to generate a surface model, which was then converted into a parametric model with 3D objects for earthwork

• 한국정밀공학회지
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• 제19권6호
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• pp.160-165
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• 2002

A study on digital processes of injection mold in reverse engineering are presented. Reverse engineering is useful fur several cases, where user has no geometry information of object. Laser scanner is used to obtaining 3D coordinates of object. Sequences to process cloud data are described; sampling to reduce number of points, sorting to adjust the point order, and fitting to curve and surface, and so on. Split slide structure of mold is used fur undercut part and high viscosity material. Flow of injection molding are analysed to correct cooling channel and simulate molding conditions. NC tool paths are generated to carve core and cavity. The processes are performed in digital data for reduction of lead time and consecutive geometry data.

• International Journal of Precision Engineering and Manufacturing
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• 제3권4호
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• pp.15-23
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• 2002

With the development of a laser scanner of high precision and increased speed, reverse engineering becomes a key approach to reduce the time for the development of new products. But the modeling process is not so automated enough until now. Modeling in real workshops is usually performed by the experienced operators and it requires a skillful technique to get the resultant surface of high quality and precision. In this paper, a systematic solution is proposed to automate the free-form surface generation from the measured point data. Compatibility is imposed to the measured point data during input curve generation. And the compatibility of cross-sectional curve is also considered for the loft surface generation. The data in each step is produced in IGES file format to make an easy interface to other CAD/CAM software without any further data manipulation.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.345-346
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• 2023

As the shape and size of detectable objects diversifying recognition and segmentation algorithms have been developed to acquire accurate shape information. Although a high density of data captured by the repetition of scanning improves the accuracy of algorithms the high dense data decreases the efficiency due to its large size. This paper proposes standardization algorithms using the feature of structural members on indoor point cloud data to improve the process. First of all we determine the reduction rate of the density based on the features of the target objects then the data reduction algorithm compresses the data based on the reduction rate. Second the data arrangement algorithm rotates the data until the normal vector of data is aligned along the coordinate axis to allow the following algorithms to operate properly. Final the data arrangement algorithm separates the rotated data into their leaning axis. This allows reverse engineering of indoor point clouds to obtain the efficiency and accuracy of refinement processes.

• 한국CDE학회논문집
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• 제6권1호
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• pp.40-47
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• 2001

In reverse engineering, existing products are digitized fur the computer modeling. Using the digitized data, surfaces are modeled for new products. However, in the digitizing process measuring errors or deviations can be happened often in practice. Thus, it is important to adjust such errors or deviations during the computer modeling. To adjust the errors, fairing of the modeled surfaces is performed. In this paper, we present a surface fairing algorithm based on various fairness metrics. Fairness metrics can be discrete. We adopt discrete metrics for fairing given 3D point set. The fairness metrics include discrete principal curvatures. In this paper, automatic fairing process is proposed for fairing given 3D point sets for surfaces. The process uses various fairness criteria so that it is adequate to adopt designers'intents.

• 한국기계가공학회지
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• 제9권1호
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• pp.74-80
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• 2010

The purpose of reverse engineering design using 3D measurement data is an accurate reconstruction of real body. In oder to accomplish this object, it is important that creating exact extracting edges should be studying out first of all. This study used edge-based method to find out edge point from the measuring point data. The characteristics are analysed using the mean curvature block method on the fitting NURBS curve and defined edges through block removal condition. The results showed that only using the NURBS curve of maximum curvature analysis to define correct edge of real geometry is limited, but this segmentation approach provides simplified necessary condition for edge classification, and an effectiveness to classify a straight line, curves and fillets etc.

• 한국생산제조학회지
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• 제9권3호
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• pp.111-122
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• 2000

It is difficult to make shape library for featrue-based modeling because free-form surface is various shaped complicated To make modeling using similar shape feature-based model is easy and fast. Recently RE(Reverse Engineering) technolo-gy is very convenient method to get free-form surface. This study develops surface editor which makes surface modeling to manipulate control points and this study We study on the effective model data management using database system.

• 터널과지하공간
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• 제17권3호
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• pp.165-174
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• 2007

3차원 레이저 스캐너를 이용하여 사물의 형상을 측정하고, 이로부터 얻어진 데이터를 이용해서 측정된 사물의 형상을 재현하는 기술을 역분석공학이라고 한다. 최근 암반공학분야에서도 사람 손이 닿지 않는 암반사면이나 넓은 지역에 대한 신속한 불연속면 조사를 위해 이러한 역분석공학 기술을 응용하고자 하는 연구가 활발히 진행되고 있다. 이러한 기술을 이용하여 불연속면을 조사하고 분석하기 위해서는 레이저 스캐너로부터 얻어진 3차원 점군데이터를 처리하고 이로부터 불연속면을 추출하고 분석하는 프로그램이 필수적이다. 그러나 기존 프로그램들은 불연속면 조사에 필요한 기능을 충분히 갖추었다고 보기 어려운 실정이다. 따라서 이 연구에서는 3차원 레이저 스캐너를 이용하여 암반면을 측정한 점군데이터로부터 불연속면을 추출하고 통계분석하는 일련의 과정을 자동화된 하나의 프로세스로 처리하는 프로그램을 개발하였으며, 개발된 프로그램을 암반 사면과 터널 벽면의 불연속면 조사에 적용하여 조사기법과 프로그램의 적용성을 검증하였다. 3차원 레이저를 이용한 불연속면 조사와 개발된 프로그램을 이용함으로써 부지 조사시 접근이 곤란한 지역의 조사 용이성이 증대될 수 있을 것으로 기대된다. 또한 관련 기술의 국제적인 수준이 초보 단계인 것을 감안하면 앞으로 해외시장 선점 가능성도 클 것으로 기대된다.