• Journal of the Korean Society of Costume
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• v.57 no.2 s.111
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• pp.45-58
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• 2007

This study shows that clothes are made just the same as the real thing in the virtual space through 3D digital technology. This study is significant to expand the area of fashion design in the virtual space. This study analyzes the practical use of the third dimension computer graphics in the aspect of fashion, and it is proposed the 3D fashion design simulation in the virtual space used on 3D studio max, poser, photoshop program according to fashion design process. The main design concept is "temporary bridge" from rainbow. "Temporary bridge" is a rainbow bridge which connects nature, man and technology, and also the past, present, and future. This study is supposed six fashion design in accordance with three sub-theme under main concept by changing rotor and texture used on 3D simulation. The conclusion are as follows : First fashion design process, which consists of design conceptualization, design definition, and computer design process, composed of body modeling, clothing modeling, texture mapping, rendering by lighting and camera establishing are compared. Second, fashion design process is applied to digital technology. Third, the method of body modeling is both that of direct modeling in 3D Studio Max and that of importing DXF file from poser. And the method of direct clothing modeling in 3D Studio Max are two methods, polygon modeling and nurbs modeling. Polygon modeling is more satisfied than nurbs modeling in the aspect of expression to clothing and round face. Forth, this study applies textures and colors transformed by photoshop on manufactured 3D Clothes. According to this result, fashion designers are able to confirm a customer or client in their design minds viewing 3D simulation by various textures. colors and angles. It is able to advance digital fashion show in the future.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.4
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• pp.451-458
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• 2007

A preliminary design approach for superyachts is introduced. The state-of-the-arts of superyachts is investigated and their characteristics are indirectly examined by analyzing the data collected from built vessels. The analysis of data provides a guideline for the establishment of an preliminary hull form of a superyacht. The rules and regulations governing the design and construction of superyachts are collected and considered. A modeling approach for prompt and efficient design is also introduced. A sample hull form of a selected superyacht is constructed using commercial design packages not only to produce a hull form but to analyze the hydrostatic and hydrodynamic performances of the constructed vessel. Various visualization techniques are considered as an efficient tool for design verification.

• International Journal of Naval Architecture and Ocean Engineering
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• v.2 no.4
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• pp.177-184
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• 2010

In this study, geometric modeling techniques and their application to ship modeling and design are presented. Traditionally the hull shape is defined by using curves called the lines and various necessary computations are performed based on the discrete points obtained from the lines. However, some applications find difficulty in using the lines such as seakeeping analysis, which requires the computation of wetted part that is changing dynamically over time. To overcome such a problem and increase accuracy and efficiency in computation, two essential geometric modeling techniques, surface modeling and surface-to-surface intersection, are introduced and their application to ship modeling and analysis including hydrostatic computation, slamming and seakeeping analyses is presented.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.3
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• pp.1026-1039
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• 2014

We present a new method for generating sweep surfaces using bivariate B-spline motion. The sweep surface is defined as the trace of a single point under bivariate B-spline motion. Direct manipulation of the sweep surface is achieved by controlling its motion components while producing various editing effects. We demonstrate the effectiveness of our technique by modeling and deforming various three-dimensional shapes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6673-6678
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• 2015

Recently, the free form buildings are constructed frequently. Exterior and interior components of these buildings have the free cross-section and a curved shape. So, There are many usages of classical finite element having tapered section and free-style shape. Some general commercial applications like ETABS, SAP2000, MIDAS are usually used for the safety evaluation of the free form structures. However, there are some limits in the accuracy of structural analysis and the length of analysis time because a very complicated finite element mesh have to be used. Therefore, In this study, a pre and post program module was developed to take advantage of general 3-D curved beam element which has a free-style curved shape and mathematical backgrounds. Pre-post processing module has been developed in this study was developed to control the curvature of the curved members by the NURBS control points. As a result, fast geometric modeling than was possible commercial applications. In addition, realistic depiction of the shape and behavior patterns were possible because of the free-form building allows visual check of the free form.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.2
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• pp.127-134
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• 2009

T-splines are recently proposed geometric modeling tools. A T-spline surface is a NURBS surface with T-junctions and is defined by a control grid called T-mesh. Local refinement can be performed very easily for T-splines while it is limited for B-splines or NURBS. Using T-splines, patches with unmatched boundaries can be combined easily without special technique. In this study, the analysis methodology using T-splines is proposed. In this methodology, T-splines are used both for description of geometries and for approximation of solution spaces. Two-dimensional linear elastic and dynamic problems will be solved by employing the proposed T-spline finite element method, and the effectiveness of the current analysis methodology will be verified.

• Transactions of Materials Processing
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• v.12 no.3
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• pp.194-201
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• 2003

An automatic quadrilateral mesh generator for large deformation finite element analysis such as metal forming simulation was developed. The NURBS interpolation method is used for modeling arbitrary 2-D free surface. This mesh generation technique is the modified paving algorithm, which is an advancing front technique with element-by-element resolving method for paving boundary intersection problem. The mesh density for higher analysis accuracy and less analysis time can be easily controlled with high-density points, maximum and minimum element size. A couple of application to large deformation finite element analysis is given as an example, which shows versatility and applicability of the proposed approach and the developed mesh generator for large deformation finite element analysis.

• Korean Journal of Computational Design and Engineering
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• v.4 no.1
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• pp.32-42
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• 1999

Approximate lofting or skinning is one of practical surface modeling techniques well used in CAD and reverse engineering applications. Presented in this paper is a method for approximately lofting a given set of curves wihin a specified tolereance. It is based on refitting input curves simultaneously on a common knot vector and interpolating them to get a resultant NURBS surface. A concept of reducing the number of interior knots of the common knot vector is well adopted to acquire more compact representation for the resultant surface. Energy minimization is newly introduced in curve refitting process to stabilize the solution of the fitting problem and get more fair curve. The proposed approximate lofting provides more smooth surface models and realizes more efficient data reduction expecially when the parameterization and compatibility of input curves are not good enough. The method has been successfully implemented in a new CAD/CAM product VX Vision? of Varimetrix Corporation.

• Korean Journal of Computational Design and Engineering
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• v.2 no.4
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• pp.222-236
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• 1997

Conventional solid or surface modeling systems cannot represent both the complete solid model and the abstract model in a unified framework. Recently, non-manifold modeling systems are proposed to solve this problem. This paper describes FlexDesigner, an open kernel system for modeling non-manifold models. It summarizes the data structure for non-manifold models, system design methodology, system modularization, and the typical characteristics of each module in the system. A data structure based on partial-topological elements is adopted to represent the relationship among topological elements. It is efficient in the usage of memory and has topological completeness compared with other published data structures. It can handle many non-manifold situations such as isolate vertices, dangling edges, dangling faces, a mixed dimensional model, and a cellular model. FlexDesigner is modularized hierarchically and designed by the object-oriented methodology for reusability. FlexDesigner is developed using the C++ and OpenGL on both SGI workstation and IBM PC.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.1
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• pp.61-67
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• 2011

This study is concerned with the shape optimization of structural members frequently found in critical area in a structure system, that is, highly stressed zone. Isogeometry analysis is well known to be the very efficient way to integrate the geometric modeling(CAD) and computational analysis(CAE). This can be accomplished by directly using the geometric modeling by NURBS(Non-Uniform Rational Basis Spline). In this study, an efficient computer code adopting the isogeometry concept has been developed for the structural analysis, in which CAD information can be directly used in the finite element modeling. In order to show the validity of the present code, the present results are compared with those by using the commercial package, that is, MSC/NASTRAN. The present isogeometric analysis procedure has been integrated with the optimization procedure to deal with the optimization problem found in the context of structural mechanics. The present system has been successfully applied to the shape optimization of cantilever structure having bracket. From the present study, it can be seen the validity of the present approach and computer codes developed in this study. This paper ends with some discussions about the practical usefulness of the present approach which is based on isogeometry analysis, and extension of the present study.