• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.7
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• pp.22-34
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• 2020

Three-dimensional (3D) computer-aided design (CAD) models require different levels of detail (LODs) depending on their purpose. Therefore, it is beneficial to automatically simplify 3D CAD assembly models to meet the desired LOD. Feature-based 3D CAD assembly models typically have the lowest and highest feasible limits of LOD during simplification. In order to help users obtain a feasible simplification result, we propose a method to simplify feature-based 3D CAD assembly models by determining the lowest and highest limits of LOD. The proposed method is verified through experiments using a simplification prototype implemented as a plug-in type module on Siemens NX.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.6
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• pp.569-578
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• 2016

With the recent advancement of surveying and technology, the spatial data acquisition rates and precision have been improved continually. As the updates of spatial data are rapid, and the size of data increases in line with the advancing technology, the LOD (Level of Detail) algorithm has been adopted to process data expressions in real time in a streaming format with spatial data divided precisely into separate steps. The existing GRID analysis utilizes the single DEM, as it is, in examining and analyzing all data outside the analysis area as well, which results in extending the analysis time in proportion to the quantity of data. Hence, this study suggests a method to reduce analysis time and data throughput by acquiring and analyzing DEM data necessary for GRID analysis in real time based on the area of analysis and the level of precision, specifically for streaming DEM data, which is utilized mostly for 3D geographic information service.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.37-38
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• 2018

BIM(Building Information Modeling) in the architecture, VDC(Virtual Design and Construction) defined CIFE(Center for Integrated Facility Engineering) of Stanford university in USA, and Data-driven design definition issued by TECDOC-1284 of IAEA are doing data-level design generated by 3D CAD technology, integrating and managing related information based on the 3D model, and Using 3D models effectively during nuclear power plant life cycle. 3D model of domestic nuclear power industry is using interference review between design fields, 4D system linked 3D construction model and schedule activity, but the 3D model generated in the design phase is effectively not utilized during the construction, operation, decommissioning. therefore, This study is aimed to suggest 3D model LOD(Level of Detail) advancement method through the analysis of existing literature, 2D drawings, and 3D models throughout nuclear power plant lifecycle.

• Journal of the Korea Society of Computer and Information
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• v.13 no.2
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• pp.105-111
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• 2008

Various visualizing methods have been proposed according to the input and output types. To show complex and large-scale raw data and information. LOD and special region scale method have been used for them. In this paper, I propose level scale interface for dynamic and interactive controlling large scale data such as bio-data. The method has not only advantage of LOD and special region scale but also dynamic and real-time processing. In addition, the method supports elaborate control from large scale to small one for visualization on a region in detail. Proposed method was adopted for genome relationship visualization tool and showed reasonable control method.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.263-267
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• 2015

Stakeholders of a construction project expect cost savings through fast and accurate cost analysis by performing BIM-based quantity take-off (BQT). However, authors have observed that there can be discrepancies in the results of BQT depending on the level of development (LOD) and modeling methods. In addition, since quantity take-off methods are different depending on the construction work items, the combination of LOD, modeling methods of BIM, features of construction work items can cause serious overestimate or underestimate in BQT results. It is necessary to identify what kind of problems can happen and how those problems can be avoided in various construction work items, since the discrepancy of quantity take-off results has great impact on not only cost analysis but also the determination of contract amount and it can cause claims, poor construction quality, cost overruns, and many others later in the construction project. Therefore, this paper focuses the identification of issues and problems of BQT at each construction work item level based on two categorizations of structural works and interior works.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.73-79
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• 2006

In this paper, we propose a new triangular finite element mesh generation method based on simplification of high-density mesh and adaptive Level-of-Detail (LOD) methods for efficient CAE. In our method, mesh simplification is used to control the mesh properties required for FE mesh, such as the number of triangular elements, element shape quality and size while keeping the specified approximation tolerance. Adaptive LOD methods based on vertex hierarchy according to curvature and region of interest, and global LOD method preserving density distributions are also proposed in order to construct a mesh more appropriate for CAE purpose. These methods enable efficient generation of FE meshes with properties appropriate for analysis purpose from a high-density mesh. Finally, the effectiveness of our approach is shown through evaluations of the FE meshes for practical use.

• Journal of KIBIM
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• v.7 no.2
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• pp.44-55
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• 2017

Recently, there has been a growing interest in the life cycle management field of buildings through the introduction of BIM. And as BIM application is expanded, BIM ordering guidelines and guidelines are becoming popular. Also, as diverse forms of buildings including super high-rise building have been generalized, attention to the importance of curtain walls that are advantageous for construction period shortening, building lighting and quality homogenization has been increasing. However, all BIM information from the design stage to the maintenance stage is not accumulated in stages. And the input information is not improved in proportion to the level of appearance of the BIM model. Also, current curtain wall designs rely heavily on curtain wall consulting firms or utilize accumulated data from existing processes. In this study, curtain wall components, shape and property information were derived by analyzing BIM guidelines and curtain wall construction standards to contribute to solving these problems. And the curtain wall smart BIM library which can be converted according to LOD(Level of Development) has been produced and its applicability has been verified. Through the library, curtain wall information can be systematically managed in the library from design to construction and maintenance. And the library will contribute to the expansion and activation of the BIM library market in the future.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.592-594
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• 1999

• Journal of the Korea Society of Computer and Information
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• v.28 no.9
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• pp.73-79
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• 2023

This paper describes a level of detail (LOD) based bending spring structure and damping technique that can reliably represent strain-based dynamics (SBD) on a triangular mesh. SBD models elastic energy using strain instead of energy based on the edge length of a triangular mesh. However, when a large external force occurs, the process of calculating the elastic energy based on edges results in a degenerate triangle, which stretches in the wrong direction because it calculates an unstable strain. In this paper, we introduce an LOD-based bending spring generation and energy calculation method that can efficiently handle this problem. As a result, the technique proposed in this paper can reliably and efficiently handle SBD based on bending springs, which can provide a stable representation of cloth simulation.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.616-625
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• 2011

There are two representative geometry rendering methods. One is Geometry Clipmaps, another is ROAM 2.0. We propose an extended Geometry Clipmaps algorithm which does not focus on CPU operation but the GPU for faster and wider visibility area. The extended algorithm presents mesh configuration method of each level by LOD, how to configurate Mesh network between levels, mesh block method for rendering optimization using VFC, and image mapping method to get high resolution up to 1 m.