• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.5 s.248
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• pp.488-495
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• 2006

The demand for the use of 3D CAD data over the Internet environment has been increased. However, transmission of 3D CAD data has delayed the communication effectiveness because of the CAD data size. Lightweight CAD file design methodology is required for rapid transmission in the distributed environment. In this paper, to derive lightweight CAD files from commercial CAD systems, a file translation system producing a native file is constructed first by using the InterOp and API of the ACIS kernel. Using the B-rep model and mesh data extracted from the native file, the lightweight CAD file with topological information is constructed as a binary file. Since the lightweight CAD file retains topological information, it is applied to the dimensional verification, digital mock-ups and visualization of CAD files. Effectiveness of the proposed lightweight CAD file is confirmed through various case studies.

• Journal of Fashion Business
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• v.10 no.6
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• pp.28-37
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• 2006

The purpose of this work is to present three-dimensional models of plain fabrics having various warp and filling yarn diameters. In order to simulate a woven fabric, a 3-dimensional CAD software with NURBS modeling capability was used. Final rendering was performed on the fabric model. It was demonstrated that the changes in yarn diameter could be three-dimensionally modeled through the use of fabric geometry and the 3D CAD. A short RhinoScript program was composed to implement the data importing and model building on the 3D CAD.

• Korean Journal of Computational Design and Engineering
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• v.8 no.3
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• pp.189-200
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• 2003

This paper introduces the development of a three-dimensional jig design system for automotive body welding assembly. Recently, three-dimensional CAD systems have been introduced in the jig design area, because they reduce errors in design process and the design result can be used readily for virtual manufacturing simulation. However, to facilitate three-dimensional jig design, it is essential to customize three-dimensional CAD system for this specific design area. To accomplish this object, we first standardized the parts and units in a jig assembly, and then built the standard part library. We also developed the dedicated 3D design capabilities of jig units and a jig base. By using this system, design can be performed more intuitively, and verification and simulation of design results can be done more easily. The proposed system has been implemented using the UG/Open API of the Unigraphics system.

• Journal of Fashion Business
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• v.17 no.1
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• pp.30-41
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• 2013

Augmented reality techniques have been increasingly employed in the textile and fashion industry as well as computer graphics sectors. Three-dimensional virtual clothing CAD systems have also been widely used in the textile industries and academic institutes. Motion tracking techniques are grafted together in the 3D and augmented reality techniques in order to develop the virtual three-dimensional clothing and fitting systems in the fashion and textile industry sectors. In this study, three-dimensional virtual clothing sample has been prepared using a 3D virtual clothing CAD along with a 3D scanning and reconstruction system. Motion of the user has been captured through an RGB-D sensor system, and the virtual clothing fitted on the user's body is allowed to move along with the captured motion flow of the user. Acutal fabric specimens are selected for the material characterization. This study is a primary step toward building a comprehensive system for the user to experience interactively virtual clothing under real environment.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.4
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• pp.432-440
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• 2008

Korean shipbuilders are starting to use three dimensional solid CAD systems to enhance their competitiveness in design and production. Despite many merits, three dimensional CAD systems reveal some problems in pipe-line modeling. Pipe-line modeling is heavily dependent on point data in routing. However, since the models built by sweeping or skinning operations do not have data about points and lines on the surfaces, the point data for routing are currently manually calculated by considering the diameters of the pipes and alignment conditions with other pipes. This process is inefficient and prone to errors. In order to enhance the pipe modeling, this paper presents an Offset Routing Program for a three dimensional CAD system, which aids designers to easily define the start points and to generate the pipe routings using reference objects.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.8
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• pp.126-134
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• 2003

In this study we do for the thing to develop automatic geometry design program of a mechanical element that we have used in CAD/CAM system. The program, which produces automatically three-dimensional surface and a solid model that have been used in CAD/CAM system, widely create automated two and three-dimensional model to by inputting several necessaries for a design, fur the design element. It is emphasized if you are just a beginner having only basic knowledge of the mechanical engineering, you might be able to design easily a three-dimensional model. The software to be used to develop automatic geometry design program is visualLISP to be a developer program of AutoCAD.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.704-706
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• 1991

In CAD/CAM system, many efforts are made to automate the converting process from drawling information to manufacturing Information. The most difficult step In this procedure is utilizing 2 dimensional drawing information In order to formulate 3 dimensional w&ling information. This paper emphasizes to mWe automatically series of convertirg steps which provide 3 dimensional wire frame, surface and solid modeling using feature recognition rules. With the standardization of design process and the recognition rule as preceding steps, it shows a good application tool to interface the design and manufacturing procedures in PC-Level CAD/CAM system.

• The Transactions of the Korea Information Processing Society
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• v.3 no.5
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• pp.1187-1197
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• 1996

In this work, two-dimensional FIR digital filter is designed and simulated using research and educational CAD tools. The two-dimensional digital filter consists mainly of one-dimensional digital filter and line memory. To speed up one-dimensional digital filter, multiplications are carried out on the basis of hardwired-shifting methods by the digital filter coefficients represented in CSD formats, while carry-save adder and Manchester adder are used in addition. It is found that the designed digital filter operates up to 30 Mhz in VHDL simulation and operates normally in IRSIM simulation for the layout made by Berkeley CAD tools.

• Korean Journal of Computational Design and Engineering
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• v.12 no.1
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• pp.39-49
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• 2007

Recently three-dimensional (3-D) die design and production process has been widely introduced into the tooling shops of automotive manufacturers to reduce time-to-production of brand-new automobiles. 3-D solid models created in CAD systems are used not only for various simulations for design verification, but also for NC tool path generation to machine dies and their Styrofoam patterns. However, a lot of time and cost will be required to build solid models for dies if designers use only the generalized modeling capabilities of commercial 3-D CAD systems. To solve this problem, it is necessary to customize 3-D CAD system for the specific die design and manufacturing process. This paper describes a dedicated 3-D CAD system based on Unigraphics for die design for automotive body panels. The system provides not only 3-D design capabilities, but also standard part libraries, to enhance design productivity. The design process modeling technology has been introduced to facilitate redesign of the die for the modified panel. By introducing this system, dies can be designed more rapidly in the 3-D space, and their solid data can be directly transferred to CAM tools for NC tool path generation and simulation tools for virtual manufacturing.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.3-6
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• 2001

The present work concerns rapid tooling technology based on three-dimensional CAD/CAM. Two types of tooling processes have been introduced : the quick delivery molding(QDM) process and the rapid tooling(RT) process using a rapid prototyping system. Both processes are based on three-dimensional CAD/CAM technology and realize a paperless manufacturing system with a high efficiency. The proposed approach has been applied to the product development for various electrical parts, and the final delivery has been reduced as compared with the traditional approach.