• 제목/요약/키워드: CSG model

검색결과 18건 처리시간 0.025초

Superquadric과 Z-버퍼 CSG 렌더링 기반의 3차원 형상 모델링 (3D Shape Reconstruction based on Superquadrics and Single Z-buffer CSG Rendering)

  • 김태은
    • 디지털콘텐츠학회 논문지
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    • 제9권2호
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    • pp.363-369
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    • 2008
  • 본 논문에서는 superquadric과 Z-버퍼 (Z-buffer) CSG (Constructive Solid Geometry) 렌더링 알고리즘을 이용한 3차원 물체 형상 모델링의 방법을 제안하였다. Superquadric은 몇 개의 계수만으로 다양한 형태의 3차원 모델을 얻을 수 있다. 그리고 CSG 트리 (tree)를 이루는 각각의 기본소 (primitive)는 superquadric과 변형된 superquadric을 가지고 표현하였다. CSG 트리를 구성하는 기본소들간의 집합 연산은 Z-버퍼 알고리즘과 스텐실 버퍼 (stencil buffer)를 사용하여 효과적으로 정의하였다. 본 논문에서 제안한 알고리즘은 단순히 물체의 깊이정보를 비교하여 표현하기 때문에 기존의 implicit 함수를 이용한 물체 표현법에서 각각의 물체의 좌표계를 고려해야 하는 문제점을 해결할 수 있다.

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An implementation of CSG modeling technique on Machining Simulation using C++ and Open GL

  • ;김수진;이종민
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회A
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    • pp.1053-1056
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    • 2008
  • An application of CSG (Constructive Solid Geometry) modeling technique in Machining Simulation is introduced in this paper. The current CSG model is based on z-buffer CSG Rendering Algorithm. In order to build a CSG model, frame buffers of VGA (Video Graphic Accelerator) should be used in term of color buffer, depth buffer, and stencil buffer. In addition to using CSG model in machine simulation Stock and Cutter Swept Surface (CSS) should be solid. Method to create a solid Cuboid stock and Ball-end mill CSS are included in the present paper. Boolean operations are used to produce the after-cut part, especially the Difference operation between Stock and CSS as the cutter remove materials form stock. Finally, a small program called MaSim which simulates one simple cut using this method was created.

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CSG 재료의 강도특성에 관한 연구 (Strength Characteristics of CSG material)

  • 박한규;김기영;조성은;전제성
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2005년도 춘계 학술발표회 논문집
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    • pp.619-626
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    • 2005
  • This work aims at studing the stress-strain-strength behavior of an CSG(cemented sand and gravel) materials. An analysis of the mechanical behavior of the CSG is performed from the interpretation of results by unconfined compression test, large triaxial compression test in which the influence of both the degree of cementation and age. For CSG, It was concluded that the characterristics of compression are direct measurment of the degree of cementation and age. In addition, hyperbolic model is adopted to express the relation between elastic moduli and cementation, age, confined stress in small strain. The results of the test show that clear correlation with each other

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솔리드 모델 변환과 특징형상인식을 위한 기하 추론 (3D Geometric Reasoning for Solid Model Conversion and Feature Recognition)

  • 한정현
    • 한국컴퓨터그래픽스학회논문지
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    • 제3권2호
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    • pp.77-84
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    • 1997
  • 3차원 물체를 표현하는 솔리드 모델링 기법으로 Constructive Solid Geometry(CSG)와 경계표현 (Boundary Representation: BRep)이 널리 쓰이고 있다. 현대의 솔리드 모델링 시스템들은 대개 이 두 기법을 모두 지원하고 있으며, CSG와 BRep간 상호 변환은 매우 중요한 문제이다. 하지만, BRep에서 CSG로의 변환은 아직 완전히 해결되지 않은 과제이다. 이 논문은 BRep을 CSG의 특수한 형태인 Destructive Solid Geometry(DSG)로 변환하는 3차원 기하 추론 알고리즘을 소개한다. BRep에서 DSG를 만들어내는 알고리즘은 CAD와 CAM을 통합시키는 특정 형상 인식 분야에 직접 응용될 수 있다.

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Application of Artificial Neural Networks for Prediction of the Strength Properties of CSG Materials

  • Lim, Jeongyeul;Kim, Kiyoung;Moon, Hongduk;Jin, Guangri
    • 한국지반환경공학회 논문집
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    • 제19권5호
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    • pp.13-22
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    • 2018
  • The number of researches on the mechanical properties of cemented sand and gravel (CSG) materials and the application of the CSG Dam has been increased. In order to explain the technical scheme of strength prediction model about the artificial neural network, we obtained the sample data by orthogonal test using the PVA (Polyvinyl alcohol) fiber, different amount of cementing materials and age, and established the efficient evaluation and prediction system. Combined with the analysis about the importance of influence factors, the prediction accuracy was above 95%. This provides the scientific theory for the further application of CSG, and will also be the foundation to apply the artificial neural network theory further in water conservancy project for the future.

임의 형상의 복합재 모델링을 위한 CSG 기반 표현 (CSG-based Representation for Free-form Heterogeneous Object Modeling)

  • 신기훈;이진구
    • 한국CDE학회논문집
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    • 제11권4호
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    • pp.235-245
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    • 2006
  • This paper proposes a CSG-based representation scheme for heterogeneous objects including multi-material objects and Functionally Graded Materials (FGMs). In particular, this scheme focuses on the construction of complicated heterogeneous objects guaranteeing desired material continuities at all the interfaces. In order to create various types of heterogeneous primitives, we first describe methods for specifying material composition functions such as geometry-independent, geometry-dependent functions. Constructive Material Composition (CMC) and corresponding heterogeneous Boolean Operators (e.g. material union, difference, intersection. and partition) are then proposed to illustrate how material continuities are dealt with. Finally, we describe the model hierarchy and data structure for computer representation. Even though the proposed scheme alone is sufficient for modeling all sorts of heterogeneous objects, the proposed scheme adopts a hybrid representation between CSG and decomposition. That is because hybrid representation can avoid the unnecessary growth of binary trees.

비다양체 모델을 수용하는 CAD 시스템 커널을 위한 불리안 조직의 개발 (Development of Boolean Operations for CAD System Kernel Supporting Non-manifold Models)

  • 김성환;이건우;김영진
    • 한국CDE학회논문집
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    • 제1권1호
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    • pp.20-32
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    • 1996
  • The boundary evaluation technique for Boolean operation on non-manifold models which is regarded as the most popular and powerful method to create and modify 3-D CAD models has been developed. This technique adopted the concept of Merge and Selection in which the CSG tree for Boolean operation can be edited quickly and easily. In this method, the merged set which contains complete information about primitive models involved is created by merging primitives one by one, then the alive entities are selected following the given CSG tree. This technique can support the hybrid representation of B-rep(Boundary Representation) and CSG(Constructive Solid Geometry) tree in a unified non-manifold model data structure, and expected to be used as a basic method for many modeling problems such as data representation of form features, and the interference between them, and data representation of conceptual models in design process, etc.

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무접합 원통형 게이트 MOSFET에서 문턱전압이동 분석을 위한 문턱전압이하 전류 모델 (Subthreshold Current Model for Threshold Voltage Shift Analysis in Junctionless Cylindrical Surrounding Gate(CSG) MOSFET)

  • 정학기
    • 한국정보통신학회논문지
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    • 제21권4호
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    • pp.789-794
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    • 2017
  • 본 논문에서는 무접합 원통형 MOSFET의 해석학적 전위분포를 이용하여 문턱전압이하 전류모델을 제시하고 이를 이용하여 문턱전압이동을 해석하였다. 무접합 원통형 MOSFET는 채널을 게이트 단자가 감싸고 있기 때문에 캐리어 흐름을 제어하는 게이트 단자의 능력이 매우 우수하다. 본 연구에서는 쌍곡선 전위분포모델을 이용하여 포아송방정식을 풀고 이 때 얻어진 중심 전위분포를 이용하여 문턱전압이하 전류 모델을 제시하였다. 제시된 전류모델을 이용하여 $0.1{\mu}A$의 전류가 흐를 때 게이트 전압을 문턱전압으로 정의하고 2차원 시뮬레이션 값과 비교하였다. 비교결과 잘 일치하였으므로 이 전류모델을 이용하여 채널크기 및 도핑농도에 따라 문턱전압이동을 고찰하였다. 결과적으로 채널 반지름이 증가할수록 문턱전압이동은 매우 크게 나타났으며 산화막 두께가 증가할 경우도 문턱전압이동은 증가하였다. 채널 도핑농도에 따라 문턱전압을 관찰한 결과, 소스/드레인과 채널 간 도핑농도의 차이가 클수록 문턱전압은 크게 증가하는 것을 관찰하였다.

Reliability of a chairside CAD-CAM surgical guide for dental implant surgery on the anterior maxilla: An in vitro study

  • Phyo Ei Ei Htay;Richard Leesungbok;Suk Won Lee;Yu-Jin Jee;Kyung Lhi Kang;Sung Ok Hong
    • The Journal of Advanced Prosthodontics
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    • 제15권5호
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    • pp.259-270
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    • 2023
  • PURPOSE. This study evaluated the reliability of the chair-side CAD-CAM surgical guide (CSG) in the anterior maxilla by comparing its accuracy with the laboratory 3D-printed surgical guide (3DSG) and manual surgical guide (MSG) concerning different levels of dentists' surgical experience. MATERIALS AND METHODS. Ten surgical guides of each type (MSG, 3DSG, and CSG) were fabricated on a control study model with missing right and left central incisors. Sixty implants were placed in 30 study models by two dentists (one inexperienced and one experienced) using three different types of surgical guides. Horizontal deviations at shoulder and at apex, vertical, and angular deviations were measured after superimposing the planned and placed implant positions in the software. Kruskal-Wallis and Mann-Whitney U tests were used to compare the accuracy of three types of surgical guides in each dentist group and the accuracy of each surgical guide between two dentists (α = .05). RESULTS. There were no significant differences in any deviations between CSG and 3DSG, apart from angular deviation, for both dentists' groups. Moreover, both CSG and 3DSG showed no significant differences in accuracy between the two dentists (P > .05). In contrast, MSG demonstrated significant differences from CSG and 3DSG and a significant difference in accuracy between the two dentists (P < .05). CONCLUSION. CSG provides superior accuracy to MSG in implant placement in the maxillary anterior region and is comparable to 3DSG at different levels of surgical experience, while offering the benefits of shorter manufacturing time and reduced patient visits.

저수지 월류 시 여수토 접속부 세굴에 따른 붕괴 현상의 실험적 연구 (An Experimental Study of Reservoir Failure Phenomena According to Transitional Zone: Spillway Scour During Overflow)

  • 김영익;연규석;김기성;정종우;김용성
    • 한국농공학회논문집
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    • 제53권2호
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    • pp.27-33
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    • 2011
  • This study is a preliminary investigation into the development of a construction method that will protect a reservoir even during over flows caused by severe flooding. Through hydraulic modeling tests, the destructive phenomena caused by spillway-junction scour during reservoir overflow were modeled, and the effects on the embankment during such an overflow and the spillway-junction movements are discussed. The reservoir destruction model used the Tanbu reservoir, located in Gangwondo Chuncheon-si Namsanmyeon (H=22 m, L=115 m), as the model reservoir and created an embankment with a 1/60 ratio. We review the spillway-junction safety factor during overflow and embankment movement following reinforcement measures for three different cases: no reinforcement, cemented sand and gravel (CSG) reinforcement and water-blocking sheet reinforcement. The results of this study confirmed that when the spillway-junction is exposed to soil, it is very vulnerable to overflow and that a water-blocking sheet or CSG reinforcement are very effective measures in preventing embankment destruction in the long-term period.