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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Korean Journal of Computational Design and Engineering
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Journal DOI :
Society of CAD/CAM Engineers
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Volume & Issues
Volume 8, Issue 4 - Dec 2003
Volume 8, Issue 3 - Sep 2003
Volume 8, Issue 2 - Jun 2003
Volume 8, Issue 1 - Mar 2003
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A Study on the Efficient Occlusion Culling Using Z-Buffer and Simplified Model
Korean Journal of Computational Design and Engineering, volume 8, issue 2, 2003, Pages 65~74
For virtual reality, virtual manufacturing system, or simulation based design, we need to visualize very large and complex 3D models which are comprising of very large number of polygons. To overcome the limited hardware performance and to attain smooth realtime visualization, there have been many researches about algorithms which reduce the number of polygons to be processed by graphics hardware. One of these algorithms, occlusion culling is a method of rejecting the objects which are not visible because they are occluded by other objects, and then passing only the visible objects to graphics hardware. Existing occlusion culling algorithms have some shortcomings such as the required long preprocessing time, the limitation of occluder shape, or the need for special hardware implementation. In this study, an efficient occlusion culling algorithm is proposed. The proposed algorithm reads and analyzes Z-buffer of graphics hardware using Microsoft DirectX, and then determines each object's visibility. This proposed algorithm can speed up visualization by reading Z-buffer using DirectX which can access hardware directly compared to OpenGL, by reading only the region to which each object is projected instead of reading the whole Z-Buffer, and the proposed algorithm can perform more exact visibility test by using simplified model instead of using bounding box. For evaluation, the proposed algorithm was applied to very large polygonal models. And smooth realtime visualization was attained.
A Study on the Real Time Culling of Infinite Sets of Geometries Using OSP Tree
Korean Journal of Computational Design and Engineering, volume 8, issue 2, 2003, Pages 75~83
In this paper, OSP(Octal Space Partitioning) tree is proposed for the real time culling of infinite sets of geometries in interactive Virtual Environment applications. And MSVBSP(Modified Shadow Volume BSP) tree is suggested for the occlusion culling. Experimental results show that the OSP and MSVBSP tree are efficiently implemented in real time rendering of interactive geometries.
A Development of Simulation Based CAD System for Automotive Rubber Machinery: An Axiomatic Design Approach
Korean Journal of Computational Design and Engineering, volume 8, issue 2, 2003, Pages 84~89
Axiomatic Design Theory is one of the most useful design methodologies which uses Functional Requirements(FRs) and Design Parameters(DPs) to make human designers more creative, to reduce the random search process, to minimize the iterative trial-and-error process, and to determine the best design among those proposed. In this research, we show how to develop a CAD system for an automotive rubber machinery using the axiomatic design approach to illustrate the effectiveness of the theory and we suggest a better way to select FRs and DPs in axiomatic design approach which can help designers to select them more effectively, objectively, and easily.
Propagation of Engineering Changes for Supporting Consistent Product Data View
Korean Journal of Computational Design and Engineering, volume 8, issue 2, 2003, Pages 90~100
Engineering change (EC) objects are the data structure and related operations that can support applications for EC procedures or processes. Their functionalities include controlling management data, specifying related product structure, and archiving a history of product structure changes for EC management. In this paper we introduce a systematic approach to support the propagation of changes between different product structure views using the history of structure changes in EC objects. The change propagations supported by EC objects enable designers to maintain the consistency of multiple product structure views for engineering, manufacturing or even customer support applications. This paper also includes EC examples and experimental implementations for the proposed EC objects.
The Development of an Product Cost Estimation System at the Product Design Stage
Korean Journal of Computational Design and Engineering, volume 8, issue 2, 2003, Pages 101~108
Presented in this paper is the development of an product cost estimation system at the product design stage. The efficient cost estimation function at the design stage is essential for the cost reduction activities through the entire product life cycle. For this purpose, it is necessary to establish a systematic working procedure, and to develop information system for managing a great deal of production and product-related data required for the cost estimation. The developed system has the capability of estimating a cost of assembly type products as well as unit-item type products. As proposed system is based on the variant approach, it can be used easily at an early design stage without the need for detail design information. Also, this system is integrated with legacy PDM (Product Data Management) and ERP (Enterprise Resource Planning) system for fast. accurate and easy product cost estimation. The estimated cost includes material cost, overhead cost as well as labor cost.
A Development of the Tire Interfacing Using the Reduction Method
Korean Journal of Computational Design and Engineering, volume 8, issue 2, 2003, Pages 109~114
In order to develop the reduced tire modal model for analyzing a full tire model, the Craig-Bampton method is utilized in this paper. When the tire contacts the road, the Abaqus solver extracts the condensed stiffness, coupled mass and mode shape matrix about the node, which contacts the road. The Abaqus full tire model is reduced using the substructure method utilizing Craig-Bampton algorithm. Then, the extracted matrices are interfaced with the superelement, which is fed to the Nastran reduction algorithm. Eventually, the reduced tire model is verified from experiment and various reduction parameters (i.e. modal number, reduction point, etc.) are studied for the effectiveness of the proposed paper.
PaperMill - A Layered Manufacturing System Using Lamination and Micro Endmill
Korean Journal of Computational Design and Engineering, volume 8, issue 2, 2003, Pages 115~121
A new Layered Manufacturing(LM) system, named PaperMill, is developed applying micro milling technology. A micro endmill(127 11m in diameter) is introduced as the cutter of build material. The selected build material for this system is an adhesive-coated paper roll which provides advantages such as good bonding between layers, machinability, and low material cost. A 3-axis CNC controller and three step-motors are used for the movement of X-Y-Z table of the system. For simplicity of the control of mechanism, the control system for feeding the paper roll is uncoupled from CNC controller. Two code converters are developed for the toolpath generation of the new LM system. The NC converter generates a set of NC codes for PaperMill using commercial CAM software while the SML converter generates an NC code from Quickslice's SML format. The NC codes generated from the converters consist of a series of profile data and trigger code for paper feeding. Two sample gears were fabricated to prove the concept of the system, which shown that the dimensional errors of the fabricated gears is under 3.4 percent.
Generation of 3D STEP Model from 2D Drawings Using Feature Definition of Ship Structure
Korean Journal of Computational Design and Engineering, volume 8, issue 2, 2003, Pages 122~132
STEP AP218 has a standard schema to represent the structural model of a midship section. While it helps to exchange ship structural models among heterogeneous automation systems, most shipyards and classification societies still exchange information using 2D paper drawings. We propose a feature parameter input method to generate a 3D STEP model of a ship structure from 2D drawings. We have analyzed the ship structure information contained in 2D drawings and have defined a data model to express the contents of the drawing. We also developed a QUI for the feature parameter input. To translate 2D information extracted from the drawing into a STEP AP2l8 model, we have developed a shape generation library, and generated the 3D ship model through this library. The generated 3D STEP model of a ship structure can be used to exchange information between design departments in a shipyard as well as between classification societies and shipyards.