• Title/Summary/Keyword: Delaunay triangulation method

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A Study on Error Verification of STL Format for Rapid Prototyping System (급속조형 시스템을 위한 STL 포맷의 오류 검증에 관한 연구)

  • Park, H.T.;Lee, S.H.
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.10
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    • pp.46-55
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    • 1996
  • As industrial standard data, the STL format which approximates three dimensional CAD model to triangular facets, is used for RP(Rapid Prototyping) system in recent days. Because most RP system take the only form of two dimensional line segments as an input stream inspite of its imperfectness while converting into STL format, a CAD model is converted into a standard industrial format which is composed of many triangular facets. The error verifying process is composed of four main steps, and these are 1) Remove facets with two or more vertices equal to each other. 2) Fix overlapping error such as more than three facets adjacent to anedge. 3) Fill holes in the mesh by using Delaunay triangulation method. 4) Correct the wrong direction and normal vectors. This paper is concerned with serching the mentioned errors in advance and modifying them.

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STL 포맷의 구멍 오류 수정을 위한 삼각형 분할법 적용에 관한 연구

  • 손영지;조연상;전언찬
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.889-893
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    • 1995
  • This paper verified error of STL file and presented a new application of reformed division method for reducing to appeared error by using Delaunay triangulation method that used to modify error of verified data. First, it is analyzed each vertices in hole error and classified follow case that is 1. case of plan or slope, 2. case of edge, 3. case of apex and 4. case of rapid curve, and reduced volume tolerance between original model and converted model after convert STL file.

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Parallel Finite Element Analysis System Based on Domain Decomposition Method Bridges (영역분할법에 기반을 둔 병렬 유한요소해석 시스템)

  • Lee, Joon-Seong;Shioya, Ryuji;Lee, Eun-Chul;Lee, Yang-Chang
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.22 no.1
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    • pp.35-44
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    • 2009
  • This paper describes an application of domain decomposition method for parallel finite element analysis which is required to large scale 3D structural analysis. A parallel finite element method system which adopts a domain decomposition method is developed. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Delaunay triangulation method is introduced as a basic tool for element generation. Domain decomposition method using automatic mesh generation system holds great benefits for 3D analyses. Aa parallel numerical algorithm for the finite element analyses, domain decomposition method was combined with an iterative solver, i.e. the conjugate gradient(CG) method where a whole analysis domain is fictitiously divided into a number of subdomains without overlapping. Practical performance of the present system are demonstrated through several examples.

Point Pattern Matching Algorithm Using Unit-Circle Parametrization

  • Choi, Nam-Seok;Lee, Byung-Gook;Lee, Joon-Jae
    • Journal of Korea Multimedia Society
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    • v.13 no.6
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    • pp.825-832
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    • 2010
  • This paper presents only a matching algorithm based on Delaunay triangulation and Parametrization from the extracted minutiae points. This method maps local neighborhood of points of two different point sets to unit-circle using topology information by Delaunay triangulation method from feature points of real fingerprint. Then, a linked convex polygon that includes an interior point is constructed as one-ring which is mapped to unit-circle using Parametrization that keep shape preserve. In local matching, each area of polygon in unit-circle is compared. If the difference of two areas are within tolerance, two polygons are consider to be matched and then translation, rotation and scaling factors for global matching are calculated.

Modified Delaunay Triangulation Based on Data Structure of Geometric Modeller (형상 모델러의 자료구조에 의한 수정 Delaunay 삼각화)

  • Chae E.-M.;Sah J.-Y.
    • Journal of computational fluids engineering
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    • v.2 no.2
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    • pp.97-103
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    • 1997
  • A modified Delaunay triangulation technique is tested for complicated computational domain. While a simple geometry. both in topology and geometry, has been well discretized into triangular elements, a complex geometry having difficulty in triangulation had to be divided into small sub-domains of simpler shape. The present study presents a modified Delaunay triangulation method based on the data structure of geometric modeller. This approach greatly enhances the reliability of triangulation, especially in complicated computational domain. We have shown that efficiency of Delaunay triangulation can be much improved by using both the GUI (Graphic User Interface) and OOP (Object-Oriented Programming).

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Reverse Engineering of 3D Compound Shapes using Delaunay Triangulation (Delaunay 삼각형분할법을 이용한 3차원복합형상의 역공학)

  • 조승현;조명우;김재도
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.7
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    • pp.181-188
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    • 2000
  • The objective of this research is to develop an efficient reverse engineering method of 3-dimensional compound surfaces for raped prototyping process. As a first step, several image processing techniques were applied to the measured data obtained using laser scanner. And the boundary information of the compound surface were extracted to divide the surface into several separate regions. As a next step, the Delaunay triangulation method were applied to reconstruct the surface based on the measured data and the boundary information. Finally, the STL file were created for the rapid prototyping process. Required simulations and experiments were performed and the results were analyzed to show the effectiveness of the proposed methods.

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Code Development of Automatic Mesh Generation for Finite Element Method Using Delaunay Triangulation Method (Delaunay 삼각화에 의한 유한요소 자동 생성 코드 개발에 관한 연구)

  • Park Pyong-Ho;Sah Jong-Youb
    • 한국전산유체공학회:학술대회논문집
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    • pp.111-117
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    • 1996
  • The Delaunay triangulation technique was tested for complicated shapes of computational domain. While a simple geometry, both in topology and in geometry, was discretized well into triangular elements. a complex geometry often failed in triangularization. A complex geometry should be devided into smaller sub-domains whose shape is simple both topologically and geometrically. The present study developed the data structures not only for relationships among neibering elements but also for shape information, and coupled these into the Delaunay triangulation technique. This approach was able to enhance greatly the reliability of triangularization specially in complicated shapes of computational domains. The GUI (Graphic User Interface) and OOP (Object-Oriented Programming) were used in order to develop the user-friendly and efficient computer code.

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A Study on Error Verification of STL format for Rapid Prototyping System (급속조형시스템을 위한 STL 포멧의 오류 검증에 관한 연구)

  • 최홍태;이석희
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.597-601
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    • 1996
  • Nowadays, the STL format, industrial standard data, which approximates three dimensional CAD model to triangular facets, is used for RP(Rapid Prototyping) system. Because most RP machine is accpted to only two dimensional line segments, but some STL translators are sometimes poorly implemented. The error verifying process is as follows. 1) Remove facets with two or more vertices equal to each other. 2) Fix overlapping error such as more than three facets adjacent to an edge. 3) Fill holes in the mesh by using Delaunay triangulation method. 4) Repair wrong direction and value of normal vectors. This paper is concerned with searching the mentioned errors in advance and modifying them.

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System Developement for STL Error Correction and Shape Modification (STL의 오류수정 및 형상수정 시스템의 개발)

  • Chae, Hee-Chang
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.3
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    • pp.53-61
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    • 1999
  • STL has several errors such as orientation error, hole error, and acute triangle error on being translated from CAD software. These errors should be corrected before using in Rapid Prototyping. So the software is necessary to correct errors. In this study, STL Editor which is a system for STL error correction and shape modification is developed and contains following characteristics. 1.Apply the triangle based data st겨cture. 2.Use the graphic user interface for easy work. 3.Use the Diet method to reduce data size. 4.Use the Delaunay triangulation method to enhance the quality of STL. 5.Modify the STL errors manually.

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Application of Delaunay Triangulation on RP (Delaunay삼각형 분할법의 RP에의 응용)

  • 명태식;채희창;김옥현
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.3
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    • pp.35-41
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    • 1999
  • STL which is used in Rapid Prototyping is composed of a lot of triangular facets. The number of triangles and the shapes of these triangles determine the quality of STL. Therefore, proper algorithm is necessary to enhance the quality of triangular patch. In this paper we used the Delaunay triangulation method to apply to following processes. 1) On processing for reducing sharp triangles which cause errors on intersection. 2) On processing for connecting two or more collinear edges. 3) On processing for deleting unnecessarily inserted points in coplanar polygon.

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