• Title, Summary, Keyword: STL

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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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Contouring Tool Path Generation for Dieless CNC Forming using STL Offset (STL offset을 이용한 다이레스 CNC 포밍용 등고선 공구경로 생성)

  • Kang Jae-Gwan;Choi Dong-Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.2
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    • pp.191-198
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    • 2006
  • Dieless CNC forming is an innovative technology which can form various materials with complex shape by numerically controlled incremental forming process. In this paper, a method of NC tool path generation based on an STL file for dieless CNC forming is proposed. Tool trajectory adopts the principle of layered manufacturing in rapid prototyping technology, but it is necessary to consider STL offset because of the ball shaped tool with a radius. Vertex offset method which enables to compute offset STL directly is engaged for STL offset. The offseted STL is sliced by cutting planes to generate contouring tool path. Algorithm is implemented on a computer and experimented on a dieless CNC forming machine to show its validity.

A 3D Watermarking on STL using Vertex domain (버텍스 영역을 이용한 STL에서의 3차원 디지털 워터마킹)

  • 김기석;천인국
    • Proceedings of the Korea Multimedia Society Conference
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    • pp.901-906
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    • 2002
  • This paper is a research about method, that is used in Rapid Prototyping system, that inserts and extracts watermark in STL(standard transform language) that has a 3D geometrical model. The proposed algorithm inserts watermark in the vertex domain of STL facet without the distortion of 3D model. If we make use of a established algorithm for watermarking of STL, a watermark inserted to 3D model can be removed by simple attack that change order of facet. The proposed algorithm has robustness about these attack. Experiment results verify that the proposed algorithm, to encode and decode watermark in STL 3D geometrical model, doesn't distort a 3D model at all. And it shows that the proposed algorithm is available.

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Verification of STL Using the Triangle Based Geometric Modeling (삼각형기반 형상모델러를 이용한 STL의 검증)

  • 채희창;황동기
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.578-582
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    • 1996
  • Verification of STL is essential in RP. In the study, triangle based non-manifold geometric modeling that can check intersection between triangles was used to vilify STL. The method proposed in this study can be applied at the most general case and very useful, but has a penalty on computing thime of O(n$^2$)

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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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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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A Digital Watermarking of 3D Geometric Model STL for Rapid Prototyping System (쾌속조형 시스템을 위한 3차원 기하학적 형상인 STL의 디지털 워터마킹)

  • 김기석;천인국
    • Journal of Korea Multimedia Society
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    • v.5 no.5
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    • pp.552-561
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    • 2002
  • In this paper, a new watermarking algorithm for STL files which contains 3D geometric information as triangular facets is proposed. STL files are widely used in rapid prototyping industry as a standard interchange format. The proposed algorithm inserts multi-bit watermark information into the surface normal vector and vertex description area of STL file without distorting the original 3D geometric information. According to the watermark bits, the position of normal vector and the direction of vertex sequence are modulated. The proposed algorithm is robust to the attack of changing the order of the triangular meshes. In addition, the invisibility requirement is also satisfied. Experiment results show that the proposed algorithm can encode and decode watermark bits into the various STL files without any distortion of 3D shape.

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Verification of STL using the Triangle Based Geometric Modeler (삼각형기반 형상모델러를 이용한 STL의 검증)

  • 채희창
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.6 no.1
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    • pp.51-58
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    • 1997
  • The verification of the STL file is essential to build the confident parts using a RP machine, because the STL file obtained from the CAD software has many errors-the orientation of triangle does not coincide with adjacent triangles or some triangles are omitted, overlpped and so forth. Especially, the STL file translated from the surface model has more errors than those translated from the solid model. In this study, all possible errors were classified with the most general from and the causes of errors were analyzed to verify and correct errors. Using the triangle based non-manifold geometric modeling, these errors were corrected. Especially, this study took the notice of the problem about the intersected triangles and non-manifold properties overlooked in the previous studies. But this study has a penalty on computing time of $O(n^2)$.

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The Study on Reduction of Scanning Path Build Time According to Control of STL file Slicing Height - Application of Small Jewellery (STL File 슬라이싱 높이 조정에 따른 주사경로 생성시간 저감에 관한 연구 - 소형 보석류에 적용)

  • Kim Tae Ho;Kim Min Ju;Lee Seung Soo;Jeon Eon Chan
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.12
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    • pp.205-210
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    • 2005
  • This paper addresses the correlation between the change of file size and the scanning path build time by the slicing height of STL file. Though the study about STL file has been achieved quite actively scanning path build time using STL file is not investigated so much to be satisfied. The file size depends on the number of polygon created by the slicing height specified. And this number of polygons increases in a regular rate. The correlation between the number of polygons and the scanning path build time is examined and verified.

A study on 3D data exchange between IGES and STL format (IGES와 SRL format 사이의 3차원 정보교고한에 관한 연구)

  • 오도근;최홍태;이석희
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.965-969
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    • 1995
  • This paper deals with effective using the IGES file for flexible data exchange among the other CAD/CAM system. If a data exchange between STL file and the neutral IGES file in Stereolithography system is available, a product design becomes more flexible. THere can be many restrictions and difficulties intranslating these data. First, an STL file follows two rules, such as right-hand rule, and vertex-to-vertex rule, thus requires a structural verification. Second, translation should be performed with minmal errors. It becomes very important to translate IGES file of limited kinds of entities fot the purpose of geometric information into STL file with minor data manipulation. The developed system suggests a good approach of translating the sampled B-spline surface of IGES and shows a potential linkage between IGES and STL format file.

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