• Korean Journal of Computational Design and Engineering
• /
• v.10 no.3
• /
• pp.162-167
• /
• 2005

A 3D solid element mesh generation algorithm was newly developed. 3D surface points of global rectangular coordinates were supplied by a 3D laser scanner. The algorithm is strait forward and simple but it generates hexahedral solid elements. Then, the surface rectangular elements were generated from the solid elements. The key of the algorithm is elimination of unnecessary elements and 3D boundary surface fitting using given 3D surface point data.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.249-250
• /
• 2002

In this paper, the relationship among the 3-D surface topography parameters are studied. Several surface topography parameters that are important in tribology are calculated against various surface topography data. 3-D surface data with desired properties are generated by using the non-causal 2-D auto-regressive (AR) model. The non-causal 2-D AR model is a random 3-D surface topography model that can generate 3-D surface topography data with specified parameters.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.28 no.11
• /
• pp.1536-1543
• /
• 2004

Garment is made by a 2D pattern and should be fitted to a human body which has 3D characteristics. Therefore, to design a pattern more effectively, the use of 3D information of a human body and the investigation of relationship between the 3D garment and 2D pattern are necessary. In this work, ruled surface method was used to reflect the 3D information of a human body for a pattern design. The images of the brassiere line on the woman's dress form were captured by phase-shifting projection moire system and the 3D information on the design line was obtained. 2D patterns on the various parts of the brassiere were developed directly from the 3D data by the ruled surface method. In addition, design line, the area and the amount of dart were quantified. And then we verify the appropriateness of the ruled surface method to the 2D pattern development by measuring the distribution of the space between women's figure and segmented clothing item. It was found that the ruled surface method is useful to transform the 3D design line to the 2D pattern, if we followed the steps suggested in this paper.

• Ocean Systems Engineering
• /
• v.6 no.3
• /
• pp.245-264
• /
• 2016

The iterative boundary element method (IBEM) developed originally before for cavitating two-dimensional (2-D) and three-dimensional (3-D) hydrofoils moving under free surface is modified and applied to the case of 2-D (two-dimensional) airfoils and 3-D (three-dimensional) wings over water. The calculation of the steady-state flow characteristics of an inviscid, incompressible fluid past 2-D airfoils and 3-D wings above free water surface is of practical importance for air-assisted marine vehicles such as some racing boats including catamarans with hydrofoils and WIG (Wing-In-Ground) effect crafts. In the present paper, the effects of free surface both on 2-D airfoils and 3-D wings moving steadily over free water surface are investigated in detail. The iterative numerical method (IBEM) based on the Green's theorem allows separating the airfoil or wing problems and the free surface problem. Both the 2-D airfoil surface (or 3-D wing surface) and the free surface are modeled with constant strength dipole and constant strength source panels. While the kinematic boundary condition is applied on the airfoil surface or on the wing surface, the linearized kinematic-dynamic combined condition is applied on the free surface. The source strengths on the free surface are expressed in terms of perturbation potential by applying the linearized free surface conditions. No radiation condition is enforced for downstream boundary in 2-D airfoil and 3-D wing cases and transverse boundaries in only 3-D wing case. The method is first applied to 2-D NACA0004 airfoil with angle of attack of four degrees to validate the method. The effects of height of 2-D airfoil from free surface and Froude number on lift and drag coefficients are investigated. The method is also applied to NACA0015 airfoil for another validation with experiments in case of ground effect. The lift coefficient with different clearance values are compared with those of experiments. The numerical method is then applied to NACA0012 airfoil with the angle of attack of five degrees and the effects of Froude number and clearance on the lift and drag coefficients are discussed. The method is lastly applied to a rectangular 3-D wing and the effects of Froude number on wing performance have been investigated. The numerical results for wing moving under free surface have also been compared with those of the same wing moving above free surface. It has been found that the free surface can affect the wing performance significantly.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.1390-1393
• /
• 2004

In the present industry, three-dimensional colored shape has required for realistic prototype in rapid manufacturing. Z-corporation developed 3D printer which can color three-dimensional prototype but this process can't be adopted to other rapid prototype products and spend much time and cost coloring 3D shape. In this study a new coloring process on three-dimensional surface is proposed for realistic prototype. Three-dimensional surface coloring apparatus is composed of HP ink jet head and X-Y plotter. Distance and angle between ink jet nozzle and 3D surface are set as process parameter. Based on the experiment of process parameters, it is shown that distance and angle affected on printed image on 3D surface. Circle and line shape are chosen as standard image shape because the shape has widely used as standard in 2D printing. Consequently, the distorted image on 3D surface is corrected by transformed input image data.

• Current Optics and Photonics
• /
• v.2 no.6
• /
• pp.568-575
• /
• 2018

Various techniques to measure the three-dimensional (3D) surface profile of a 3D micro- or nanostructure have been proposed. However, it is difficult to apply such techniques directly to industrial uses because most of them are relatively slow, unreliable, and expensive. The HiLo optical imaging technique, which was recently introduced in the field of fluorescence imaging, is a promising wide-field imaging technique capable of high-speed imaging with a simple optical configuration. It has not been used in measuring a 3D surface profile although confocal microscopy originally developed for fluorescence imaging has been adapted to the field of 3D optical measurement for a long time. In this paper, to the best of our knowledge, the HiLo optical imaging technique for measuring a 3D surface profile is proposed for the first time. Its optical configuration and algorithm for a precisely detecting surface position are designed, optimized, and implemented. Optical performance for several 3D microscale structures is evaluated, and it is confirmed that the capability of measuring a 3D surface profile with HiLo optical imaging technique is comparable to that with confocal microscopy.

• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.3 no.1
• /
• pp.61-70
• /
• 2005

The purpose of study correlation between 3D-surface topography and Cobb angle in scoliotic patients. It would be recognizing possibility of clinical application with 3D-surface topography with scoliosis assessment and correlation analysis of obtained Cobb angle through measured results of surface topography and took X-ray of subjects with scoliosis, which used to 3D-surface topography of laser scan method. A scoliosis subjects 16(males 4, females 12) agreed for study's purport volunteer our study that diagnose the scoliosis through 3D-surface topography and X-ray. The results were as follow: It was shown that the relation of Cobb angle of scoliosis and itemized 3D-surface topography measurement in horizontal view(p<0.01). top difference of cervicothoracic and lumbar in anterior-posterior view(p<0.05), the top difference of thoracic, thoracolumbar(p<0.01). These results suggest that an itemized 3D-surface topography measurement was highly correlated with Cobb angle. It would be a useful diagnosis method and assessment of physical therapy plan.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.6 no.4
• /
• pp.632-638
• /
• 2002

Extensible 3D(X3D) is a software standard for defining interactive web and broadcast-based 3D content integrated with multimedia. The data size of Web3D representation based on polygon meshes is so large that transferring practical data fast is a hard problem. This paper proposes 3D object structure, a new framework for compact 3D representation with high quality surface shape. By utilizing a free form surface technique, qualified surface are transferred with limited amount of data size and rendered. 3D graphic structure can be regarded ad both polygon meshes and free form surfaces. Therefore, it can be easily integrated to existing Web3D data formats, for example VRML ＆ XML. 3D object structure also enables modeling free form surface shapes intuitively with polygon modeling like operations.

• The korean journal of orthodontics
• /
• v.42 no.4
• /
• pp.169-181
• /
• 2012

Objective: The purpose of this study was to develop superimposition method on the lower arch using 3-dimensional (3D) cone beam computed tomography (CBCT) images and orthodontic 3D digital modeling. Methods: Integrated 3D CBCT images were acquired by substituting the dental portion of 3D CBCT images with precise dental images of an orthodontic 3D digital model. Images were acquired before and after treatment. For the superimposition, 2 superimposition methods were designed. Surface superimposition was based on the basal bone structure of the mandible by surface-to-surface matching (best-fit method). Plane superimposition was based on anatomical structures (mental and lingual foramen). For the evaluation, 10 landmarks including teeth and anatomic structures were assigned, and 30 times of superimpositions and measurements were performed to determine the more reproducible and reliable method. Results: All landmarks demonstrated that the surface superimposition method produced relatively more consistent coordinate values. The mean distances of measured landmarks values from the means were statistically significantly lower with the surface superimpositions method. Conclusions: Between the 2 superimposition methods designed for the evaluation of 3D changes in the lower arch, surface superimposition was the simpler, more reproducible, reliable method.

• Korean Journal of Computational Design and Engineering
• /
• v.10 no.1
• /
• pp.70-75
• /
• 2005

A 3D solid element mesh generation algorithm was newly developed. 3D surface points of global rectangular coordinates were supplied by a 3D laser scanner. The algorithm is strait forward and simple but it generates mixed solid elements such as hexagonal, pyramid and prism types. Then, the surface triangular or rectangular elements were generated from the solid elements. The key of the algorithm is elimination of elements and 3D adaptive surface smoothing using given 3D surface point data.