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

• Journal of the Society of Naval Architects of Korea
• /
• v.41 no.1
• /
• pp.75-81
• /
• 2004

In this study surface modeling .method with 3D curve net is proposed. For surface modeling, ship hull was divided into several parts, Generated surface was loaded general purpose CAD program through IGES file format, and the quality of generated surface model was checked by CATIA's internal function. Lastly it is tried to find a method for improving the accuracy of surface connection by using the blending method in CATIA and the result was discussed.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.9 no.3
• /
• pp.111-122
• /
• 2000

It is difficult to make shape library for featrue-based modeling because free-form surface is various shaped complicated To make modeling using similar shape feature-based model is easy and fast. Recently RE(Reverse Engineering) technolo-gy is very convenient method to get free-form surface. This study develops surface editor which makes surface modeling to manipulate control points and this study We study on the effective model data management using database system.

• Journal of Korea Multimedia Society
• /
• v.19 no.11
• /
• pp.1900-1908
• /
• 2016

Recent times have seen the introduction of modeling technologies using implicit surface and marching cubes algorithm in the field of computer graphics. Implicit surface modeling is used to express characters or fluid. This study presents a calculation method for the density of curve skeletal primitives using parametric curve and implements an implicit surface modeling tool by utilizing Maya API. Skeletal primitives can be assembled and utilized in character modeling using the implemented modeling tool. Results could be obtained more effectively compared to existing particle-based methods.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.5 no.2
• /
• pp.20-28
• /
• 1996

Compound surface modeling is widely used for die cavities and punches. A compound surface is defined in 3-D space by specifying the topological relationship of several anlytic surface elements and a sculptured surface. A constructive solid gemonetry scheme is employed to model the analytic compound surface. the desired compound surface can be accomplished by specifying topological reationship in terms of boolean relations between pimitives and the sculptured surfaces. Additionally, a method is presented for checking and avoiding the tool interference occuued in machining the compound surface. Using this method. the interference of concave, convex, and side region can be checked easily and avoided rpapidly.

• Journal of the Society of Naval Architects of Korea
• /
• v.34 no.4
• /
• pp.127-138
• /
• 1997

In this study, a new technique is presented, by which one can define ship hull form with full fairness from the input data of lines. For curve modeling, the de Casteljau Algorithm and Bezier control points are used to express free curves and to establish the unified curve modeling technique which enables one to convert non-uniform B-spline (NUB) curve or cubic spline curve into composite Bezier curves. For surface modeling, the mesh curve net which is required to define surface of ship hull form is interpolated by the method of the unified curve modeling, and the boundary curve segments of Gregory surface patches are generated by remeshing(rearranging) the given mesh curve net. From these boundary information, composite Gregory surfaces of good quality in fairness can be formulated.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2010.04a
• /
• pp.235-238
• /
• 2010

Since the mid 1990s airborne LiDAR data have been widely used, automation of building modeling is getting a central issue. LiDAR data processing for building modeling is involved with extracting surface patch elements by segmentation and surface fitting with optimal mathematical functions. In this study, simulation LiDAR data were generated with complex polyhedral roofs of buildings and an automatic modeling approach was proposed.

• Korean Journal of Computational Design and Engineering
• /
• v.3 no.4
• /
• pp.293-303
• /
• 1998

The objective of this study is to develop a PC level freeform surface modeling system which explicitly represents information of part geometry. Surface modeler uses nonuniform rational B-spline (NURBS) function with nonuniform knot vector for the flexible modeling work. The results of this study are as follows. 1) By implementation surface modeler through applying representation scheme proposed to represent free-form surface explicity, the technical foundation to develop free-from surface modeling system using parametric method. 2) Besides the role to model geometric shape of a surface, geometric modeler is developed to model arbitrary geometric shape. By doing this, the availability of the modeling system is improved. Geometric modeler can be utilized application fields such as collision test of tool and fixture, and tool path generation for NC machine tool.

• Journal of the Society of Naval Architects of Korea
• /
• v.45 no.6
• /
• pp.601-610
• /
• 2008

This paper deals with a new geometrical surface modeling method of forebody's hull form which is fully defined by form parameters. The complex hull form in the forebody can be modeled by the combination of three parts: bare hull, bulbous bow and blending part which connects a bare hull and a bulbous bow. All these subdomain parts are characterized by each own form parameters and constructed with simple surface model. For this, we need only 2-dimensional hull form data and then the form parameters are calculated automatically from these data. Finally, the smooth hull form surfaces are generated by parametric design and fair-skinning. In the practical point of view, we show that this new method can be useful and efficient modeling tool by applying to the hull form surface modeling of Panamax container's forebody.

• Journal of Environmental Science International
• /
• v.8 no.2
• /
• pp.211-219
• /
• 1999

Surface complexation models(SCMs) have been performed to predict metal ion adsorption behavior onto the mineral surface. Application of SCMs, however, requires a self-consistent approach to determine model parameter values. In this paper, in order to determine the metal ion adsorption parameters for the triple layer model(TLM) version of the SCM, we used the zeta potential data for Zeolite and Kaolinite, and the metal ion adsorption data for Pb(II) and Cd(II). Fitting parameters determined for the modeling were as follows ; total site concentration, site density, specific surface area, surface acidity constants, etc. Zeta potential as a new approach other than the acidic-alkalimetric titration method was adopted for simulation of adsorption phenomena. Some fitting parameters were determined by the trial and error method. Modeling approach was successful in quantitatively simulating adsorption behavior under various geochemical conditions.