• Korean Journal of Computational Design and Engineering
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• v.7 no.4
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• pp.211-218
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• 2002

Swept volumes have been used in a wide variety of applications, and the literature contains much discussion of methods for computing the swept volumes in many situations. However, the commercially available CAD systems do not support the operations of generating the swept volumes enough to satisfy a variety of users' needs. In this paper, we present a new, simple and efficient algorithm for computing the swept volume of moving a polyhedron in 3-D region. The screw motion is used to describe the sweep motion of a polyhedron, because of its simplicity and computational advantages. The boundary of a swept volume is the result of combining the envelope surfaces and the partial boundaries at the initial and final position of a polyhedron. Some portions of these boundaries are inside the swept volume. We develop the algorithm to remove these interior portions. Then, to implement our algorithm, it is performed to integrate our program with the commercial CAD software, CATIA.

• Journal of The Korean Association of Information Education
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• v.21 no.4
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• pp.451-462
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• 2017

This study selected 3D printing that is highly likely to be adopted in schools. This research was conducted in two stages: 1) proposing the learning activity framework for utilizing 3D printing in education, and 2) exploring the potential of integrating 3D printing in the school field. The '3D printing learning activity framework' proposed in this study includes four phases that are categorized according to the complexity of problem-solving processes and collaborative interaction: Step 1 as production through replication, Phase 2 as means of imaginary expression, Phase 3 as near problem-solving, and Phase 4 as expanded problem-solving. Next, we conducted the field study with 23 students in the 6th grade math class where they learned the various solid shapes and volumes through 3D printing-integrated activities. The lesson was considered as Phase 1, which is the production through replication. Overall, the results showed that the participants had positive perceptions about the efficacy of 3D printing activities, the quality of learning experience, and satisfaction. On the other hand, it was found that the usability of 3D printers and CAD program needs further improvement The contribution of this study can be found in the learning activity framework that can guide 3D printing activity design in school, and in the exploration of enhancing the connection between 3D printing activities and curricular relevance beyond simple interest toward a novel technology.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.111-118
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• 2023

The purpose of this study is to study jewelry designs presented to general consumers who seek new products and diversity. We would like to present a modular jewelry design with a structure and combination method that is distinct from jewelry in a multimodal replacement method that allows various product modules sold in the past to be worn interchangeably. Problems are likely to occur when a number of existing rather small parts are manufactured in a complex combination method, and difficulties may follow when consumers replace decorative parts and lose them in the process of assembling small fixture parts. Therefore, in order to reduce these problems, we try to make it different from jewelry products made with a simple and simple design so that it can be easily replaced and worn without the need for other coupling parts, and produced using the latest 3D printer (Rapid Prototyping). In this study, based on the experience and know-how gained while engaging in field work, it was possible to make a real object and focused on minimizing problems during the production process, and through this, time and economic loss can be reduced. The purpose of the study is to produce improved jewelry products by expressing more sophisticated and differentiated shapes by using 3D programs (CAD).

• Journal of the Korean Society of Costume
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• v.54 no.4
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• pp.63-74
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• 2004

This study shows that clothes to be just the same as the real thing can be Produced through the third dimension computer graphics, and then presents that not only the area of fashion design can be expanded in the virtual reality field by doing the simulation of the fashion show, but also the information can be made the real time public ownership and the communication can be fulfilled smoothly. In this study, analyzing the third dimension computer graphic programs to be used much at present, Alias Wavefront Company's Maya software which was the most effective in the clothes simulation and the clothes CAD SGS OptiTex 8.7 which went well substitutive for it were used of them. The conclusions of this study that got through the work manufacture are as follows： The first, if the file manufacturing in the clothes CAD by using the computer was stored, the pattern used 3D simulation was available because it could be summoned in 3D software. The second, if the data of DXF form in Maya program was summoned, they could not be applied by Maya Cloth supported in Nurbs only because they were recognized as the DXF＿layer. So the curve along the outer lines of the pattern was drawn and Maya Cloth was applied to be possible to get the natural silhouette of clothes. The third, when the clothes were manufactured by 3D, if the draping character was applied according to the textile special quality, not only the control of textile's thickness, weight, quality feeling, and silhouette was available, but also the clothes were available to graft the special textile materials. The fourth, the natural motion of model was produced by capturing the actual model's walking action In order to produce the fashion show motion and also the dynamic fashion show was available by the angle of camera, the establishment of lighting, and etc. in the final rendering. The clothes manufactured by 3D are available to change the design by changing the materials, or by adding the details, or by utilizing the special materials on clothes. Therefore, the trial and error following at the clothes manufacture can be reduced. But the elevation of the rendering speed, the price down, the strengthening of personal security, and etc. are required.

• The Journal of the Korean dental association
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• v.58 no.1
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• pp.19-26
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• 2019

Purpose: The purpose of this study is to compare the adhesion of Candida albicans according to build angle in 3D printing denture base resin. Methods: The 3D printing was performed by setting the build angle of the disk type specimen designed by CAD program at 0 degree, 30 degrees, 60 degrees, and 90 degrees. Surface roughness was measured using a non-contact 3D microsurface profiler. The specimens were incubated in Candida albicans suspension for 24 hours. The attached Candida albicans were detached by cell scraper. The suspension of detached C. albicans was serially diluted and plated on Trypticase soy broth. After 48 hours of incubation, total colony forming unit was counted. Results: There was no significant difference in surface roughness(Sa) between the test groups, but the interlayer boundary was observed. There was no statistically significant difference in total colony forming units of Candida albicans between the test groups. Conclusion: There was no difference in the average surface roughness and adhesion of Candida albicans between the specimens. It is considered that the setting of the build angle should be set considering the accuracy or strength rather than the roughness of the surface.

• The Journal of the Korean dental association
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• v.57 no.2
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• pp.100-104
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• 2019

Orthognathic surgery is designed to correct problems of the jaw and face and restore facial harmony. The limitations of orthognathic surgery occur at all steps of the surgical workflow: preoperative planning, simulation, and operation. Many studies have shown the accuracy and advantages of 3 dimensional computer-assisted program for orthognathic surgery. The purpose of this paper is to introduce the accuracy of the maxillary repositioning in patients who underwent orthognathic surgery using a 3 dimensional computer assisted surgery program. The reliability of computer guided orthognathic surgery using splint and surgical guide need to be improved further. The 3 dimensional computer assisted analysis seems to be more precise to interpret than two-dimensional analysis. High-precision planning of orthognathic surgery has predictable results. Three-dimensional computer assisted orthognathic surgery has the following advantages : planned surgical movement is possible, splints guide with CAD/CAM technology; and increase predictable results .Computer assisted simulation surgery ensures accuracy during surgery, thereby facilitating predictable results. It may provide solution that enables surgeon to perform planned surgery more accurately.

• Journal of KIBIM
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• v.3 no.3
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• pp.9-18
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• 2013

In case of applying the BIM method in the civil engineering of irregularly shaped structure, BIM method began to be introduced in the current building engineering area compared with the expected effects of the relatively high construction productivity has been recognized. In this paper, I have developed quantity calculation algorithms applying it to earthwork and bridge construction, tunnel construction, retaining wall construction, culvert construction and implemented BIM based 3D-BIM Modeling quantity calculation. Structure work in which errors occurred in range between -6.28% ~ 5.17%. Especially, understanding of the problem and improvement of the existing 2D-CAD based of quantity calculation through rock type quantity calculation error in range of -14.36% ~ 13.07% of earthwork quantity calculation. It's benefit and applicability of BIM method in civil engineering. In addition, routine method for quantity of earthwork has the same error tolerance negligible for that of structure work. But, rock type's quantity calculated as the error appears significantly to the reliability of 2D-based volume calculation shows that the problem could be. Through the estimating quantity of earthwork based 3D-BIM, proposed method has better reliability than routine method. BIM, as well as the design, construction, maintenance levels of information when you consider the benefits of integration, the introduction of BIM design in civil engineering and the possibility of applying for the effectiveness was confirmed. In addition, as the beginning phase of information integration, quantity document automation program has been developed for activation of BIM. And automatically enter the program code number, linkage and manual volume calculation program, quantity document automation programs, such as the development is now underway, and step-by-step procedures and methods are presented.

• Journal of the Korean Society of Clothing and Textiles
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• v.43 no.2
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• pp.204-214
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• 2019

A CAD program has recently been introduced that can be directly developed into a three-dimensional human body shape and made into a pattern. It is possible to fabricate a bra that reflects the volume and surface area of the breast; however, it still needs to be verified. This study investigates the average size and shape of 20 big-breasted women and designs a brassiere pattern for women with large breasts using a 3D Flattening function of OptiTex PDS v15.6. In addition, the study verifies the reliability of the proposed method compared to a conventional brassiere pattern. The study results are as follows. First, the three dimensional measurement values were smaller than the direct measurement dimensions when the three dimension measurement dimensions of the subjects were compared with the direct measurement dimensions, the replica measurement dimensions and the three dimensional measurement dimensions. Second, the 3D flattening pattern reflects the actual shape, length, and area of the actual breast when comparing a brassiere pattern using a 3D shape and pattern reflecting the direct measurement.

• Design & Manufacturing
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• v.11 no.3
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• pp.19-24
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• 2017

In these days, increase requirement of TEM (Transmission Electro Microscope) in not only scientific field but also industrial field. Because TEM can measure inner-structure of specimen a variety of materials like metal, bio. etc. When use TEM, specimen should be thin about 50nm. So making for thin specimen, use Ion milling device that include specimen holder. The holder generally made of Aluminium Aluminium holder is worn away easily. For this reason, using time of ion milling with aluminum holder is too short. To solve the problem, we replace aluminium holer to molybdenum alloy holder. In this paper, we design molybdenum alloy holer for CAM and modify CAD modeling for effective machining process. So we array a specimen 3 by 4 and setup orientation for one-shot machining process. Next we make a CAM program for machining. we making a decision two machining strategy that chose condition of tool-path method, step-down, step-over. etc. And then conduct machining using CNC milling machining center. To make clear difference between case.1 and case.2, we fixed machining conditions like feed-rate, main spindle rpm, etc. After machining, we confirm the condition of workpiece and analysis the problems case by case. Finally, case.2 work piece that superior than case.1 cutting with WEDM because that method can not ant mechanical effect on workpiece.

• The Research Journal of the Costume Culture
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• v.24 no.6
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• pp.725-742
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• 2016

In the Korean fashion industry, 3D printing systems are considered as new technology and a new opportunity. With 3D printers, consumers can be manufacturers and individuals can develop businesses with little upfront capital. In this study, a dress form for the typical Korean women's body shape was developed using 3D technology (3D scanning, 3D modeling, and 3D printing). Ten women with apparel sizes 85-91-160 were selected from 3D body-scan data collected by SizeKorea of 201 women aged 25 to 34 (2010). First, 15 horizontal cross-sections were collected from the 3D scan data of the 10 subjects. Then, inside lines of those cross-sections were drawn at 15-degree intervals, and the lengths were measured. The average of the inside lines was connected to the internal spline curve, and the curves were used as the average cross-sections. The average torso body and the dress form of Korean women were developed into a 3D solid model using a 3D CAD program (Solidworks 2012). An output mockup was printed by the FDM type's 3D printing system (Bonbot 1200, Bonbot 3-H4) using PLA material. The dimensions comparing the 3D solid modeling to the 3D printed mockup of the dress form were measured, and minor differences were between 0.00cm and 0.40cm. In the future, 3D printing systems are expected to be in use for various personalized dress forms.