• International journal of advanced smart convergence
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• v.6 no.1
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• pp.9-17
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• 2017

Recent development in virtual and augmented reality increases the demand for content in many different fields. One of the fast ways to create content for VR is 3D modeling of real objects. In this paper we propose a system to reconstruct three-dimensional models of real objects from the set of two-dimensional images under the assumption that the subject does not has distinct features. We explicitly consider an object that is made of one or more surfaces and radiant constant energy isotropically. We design a low cost portable multi camera rig system that is capable of capturing images simultaneously from all cameras. In order to evaluate the performance of the proposed system, comparison is made between 3D model and a CAD model. A simple algorithm is also proposed to acquire original texture or color of the subject. Using best pattern found after the experiments, 3D model of the Pyeongchang Olympic Mascot "Soohorang" is created to use as VR content.

• Journal of Korea Game Society
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• v.17 no.6
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• pp.19-28
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• 2017

There exist a variety of VR(Virtual Reality) contents that have been developed by the use of the latest VR technologies. Unlike the rapid advances in the recent VR devices however, the development of VR based game contents that fully utilize such cutting-edge devices has been lackluster. Using more accessible form of smartphone-based HMDs(Head-Mounted Displays), we compare two popular VR presentation methods(a realistic 3D VR karaoke room and a 360 degree video karaoke room) and analyze their users' immersion and realistic perception. We expect that our study can be utilized as a supporting guideline for future smartphone-based VR content developments.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.8 s.227
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• pp.1116-1124
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• 2004

In these days, a vehicle simulator has been developed with a VR(Virtual Reality) system. A VR system must provide a vehicle simulator with natural interaction, sufficient immersion and realistic images. In addition, a VR system must present a driver with the realistic driving situation. To achieve these, it is important to obtain a fast and uniform rendering performance regardless of the complexity of virtual worlds. In this paper, the factors to improve the reality for the VR based vehicle simulator have been investigated. For the purpose, the modeling and the rendering methods which offer an improved performance for complex VR applications as the 3D road model have been implemented and verified. Then, we experiment on the influence of graphic and sound factors to the driver, and analyze each result for improving the reality such as the driver's viewport, the form of texture, the lateral distance of the side object, and the sound effect. These factors are evaluated on the driving system which is constructed for qualitative analysis. The research results could be used for improving the reality of the VR based vehicle simulator.

• Wind and Structures
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• v.7 no.1
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• pp.13-28
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• 2004

A method of numerical analysis without conducting 3D wind tunnel model tests was examined in our previous study for predicting vortex-induced oscillation of bridge girders with span-wise varying geometry. The aerodynamic damping forces measured for plural wind tunnel 2D models were used in the analysis. A further study was conducted to examine the precision of solution obtained by this method. First, the responses of vortex-induced oscillation of two rocking models and a taut-strip bridge girder model with span-wise varying geometry were measured. Next, the responses of these models were numerically analyzed by means of this method, and then a comparison was made between the obtained $Vr-A-{\delta}_a$ contour diagram of each 3D model in the wind tunnel test and the diagram in the numerical analysis. Since close correlations were observed between each two $Vr-A-{\delta}_a$diagrams obtained in the model test and in the analysis in cases where the 3D model did not have strong three-dimensionality, our findings revealed that the predicted solution proved to be reasonably accurate.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.26 no.3
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• pp.285-288
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• 2022

Three-dimensional (3D) modeling of the liver can be especially useful for both the surgeon and patient to understand the actual location of the tumor and planning the resection plane. Virtual reality (VR) can enhance the understanding of 3D structures and create an environment where the user can focus on contents provided. In the present study, a VR platform was developed using Unreal Engine 4 software (Epic Games, Potomac, MD, USA). Patient's liver based on magnetic resonance image was imported as a 3D model that could distinguish liver parenchyma, vascular structure, and cancer. Preoperative education videos for patients were developed. They could be viewed inside the VR platform. To evaluate the usefulness of VR education program for patients undergoing liver resection for hepatocellular carcinoma, a randomized clinical trial evaluating the knowledge and anxiety of the patient was designed. The case presented in this report was the first experience of performing the VR education program and examining the knowledge and anxiety using questionnaires. When the knowledge score increased, the anxiety score also increased after the education program. Based on findings of this pilot case study, the timing and place where the questionnaire will be answered can be modified for formal initiation of the randomized controlled study to examine the usefulness of VR in patient education.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.125-130
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• 2011

This paper investigates the possibility of exploiting haptic force-feedback technology for interacting with Nanta music. We use VR technologies including touch processing technologies and haptic devices to offer touch of cylinder objects and cup object to users. Haptic device is used to implement touch model in VR space. Matlab/Simulink and proSENCE Virtual Touch Toolbox of Handshake Inc. for experiment, are used as programing tools. Function needed to describe the movement of x, y, and z axis respectively are applied to delineate the natural movement of water in cup object modeled with 3D. A certain amount of water in cup object has the difference of sounds. In experiment, to perceive the appearance of 3D object by touch and to feel the tactile by touch are conducted with the effect of sound on Haptic perception. We also verify that it is possible to develop games or contents in VR space by using point.

• Steel and Composite Structures
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• v.27 no.6
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• pp.717-725
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• 2018

One of the most important design criteria in military tunnels and armoured doors is to resist the blast loads with minimum structural weight. This can be achieved by using steel sandwich panels. In this paper, the nonlinear behaviour of steel sandwich panels, with different core materials: (1) Hollow (no core material); (2) Rigid Polyurethane Foam (RPF); and (3) Vulcanized Rubber (VR) under free air blast loads, was investigated using detailed 3D nonlinear finite element models in Ansys Autodyn. The accuracy of the finite element model proposed was verified using available experimental test data of a similar steel sandwich panel tested. The results show the developed finite element model can be reliably used to simulate the nonlinear behaviour of the steel sandwich panels under free air blast loads. The verified finite element model was used to examine the different parameters of the steel sandwich panel with different core materials. The result shows that the sandwich panel with RPF core material is more efficient than the VR sandwich panel followed by the Hollow sandwich panels. The average maximum displacement of RPF sandwich panel under different ranges of TNT charge (1 kg to 10 kg at a standoff distance of 1 m) is 49% and 53% less than the VR and Hollow sandwich panels, respectively. Detailed empirical design equations were provided to quantify the maximum deformation of the steel sandwich panels with different core materials and core thickness under a different range of blast loads. The developed equations can be used as a guide for engineer to design steel sandwich panels with RPF and VR core material under a different range of free air blast loads.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.287-293
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• 2018

The Korean peninsula has been known as an area that is free of volcanic disasters. However, recent observations and research results of volcanoes in Far East Asia, including Baedu Mountain and Japanese volcanoes, show that the Korean peninsula is no longer a safe area from volcanic disasters. Since 2012, the Korean government has been developing an IT-based construction technology, VDRS (Volcanic Disaster Response System), for effective volcanic disaster response system. The main users of VDRS are public officers in central or local governments. However, most of them have little experience and knowledge about volcanic disasters. Therefore, it is essential to develop education contents and implement training on volcanic disaster response for effective response in a real disaster situation. In this paper, we deal with the development of a mobile application based on virtual reality (VR) for realistic volcanic disaster response training. The objectives of training are the delivery of knowledge and experience for volcanic disasters. First, VR contents were generated based on spatial information. A 3D model was constructed based on a Digital Elevation Model (DEM), and visualization models for meterological effects and various volcanic disaster diffusion effects were implemented for the VR contents. Second, the mobile application for the volcanic disaster response training was implemented. A 12-step story board is proposed for volcanic disaster experience. The application was developed with the Unity3D engine based on the proposed story board to deliver knowledge of various volcanic disasters (volcanic ash, pyroclastic flows, volcanic mudflow etc.). The results of this paper will be used for volcanic disaster response and prevention training and for more realistic training linked with augmented reality technology in the future.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.248-249
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• 2019

In the nuclear industry, in order to keep pace with the 4th industrial revolution era, they are trying to improve the construction and maintenance ability by utilizing the technologies such as digital twin and VR/AR from the construction stage. However, the nuclear 3D CAD model, which is used as the base in the latest technology, is heavy due to a large number of facilities per unit space compared to other industrial companies, and it is difficult to directly incorporate the latest technology into the results of CAD programs for design purposes. In this study, in order to improve usability, we tried to lighten the 3D model. First, we analyze the existing nuclear power plant 3D model and draw out the problems and features. Secondly, we derived the factors to consider when we make the 3D CAD models lightweight.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.2
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• pp.181-189
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• 2021

In order to increase the practical usability of the virtual reality(VR)-based BIM object in the construction site, the difference between the virtual image and the real image should be resolved, and when it is applied to the construction schedule management function, it is necessary to reduce the image gap between the virtual completion and the actual completion. In this study, in order to solve this problem, a prototype of 4D model is developed in which augmented reality (AR) and 3D printing technologies are linked, and the practical usability of a 4D model linked with two technologies is verified. When a schedule simulation is implemented by combining a three-dimensional output and an AR object, it is possible to provide more intuitive information as a tangible image-based schedule information when compared to a simple VR-based 4D model. In this study, a methodology and system development of an AR implementation system in which subsequent activities are simulated in 4D model using markers on 3D printing outputs are attempted.