• Structural Engineering and Mechanics
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• v.68 no.1
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• pp.17-38
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• 2018

In this paper, we compare and assess the performance of the standard 3- and 6-node MITC shell elements (Lee and Bathe 2004) with the recently developed MITC triangular elements (Lee et al. 2014, Jeon et al. 2014, Jun et al. 2018) which were based on the partitions of unity approximation, bubble node, or both. The convergence behavior of the shell elements are measured in well-known benchmark tests; four plane stress tests (mesh distortion test, cantilever beam, Cook's skew beam, and MacNeal beam), two plate tests (Morley's skew plate and circular plate), and six shell tests (curved beam, twisted beam, pinched cylinder, hemispherical shells with or without hole, and Scordelis-Lo roof). To precisely compare and evaluate the solution accuracy of the shell elements, different triangular mesh patterns and distorted element mesh are adopted in the benchmark problems. All shell finite elements considered pass the basic tests; namely, the isotropy, the patch, and the zero energy mode tests.

• Journal of Korea Game Society
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• v.21 no.2
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• pp.79-88
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• 2021

Particle and noise are effectively used to implement unspecific VFX like an explosion, magic. Particle can create freely but, The more usage, the higher CPU/GPU usage. This paper using polygon mesh that is hard to change but consumes fixed resources to overcome the demerit of particle and reduce CPU/GPU usage. Also, using shader, apply noise texture that is suitable unspecific pattern to vertex and surface texture mapping of polygon mesh for implement VFX in unity. As a result of experiment, shader applied sphere polygon mesh show 2~4ms CPU, 1~2ms GPU usage in profiler. Also It has been shown that shader can be used to implement unspecific VFX.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.2
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• pp.249-256
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• 2022

Various studies are being actively conducted to show that the real-time visualization technology that combines BIM (Building Information Modeling) and AR (Augmented Reality) helps to increase construction management decision-making and processing efficiency. However, when large-capacity BIM data is projected into AR, there are various limitations such as data transmission and connection problems and the image cut-off issue. To improve the high efficiency of visualizing, a mesh optimization algorithm based on the k-nearest neighbors (KNN) classification framework to reconstruct BIM data is proposed in place of existing mesh optimization methods that are complicated and cannot adequately handle meshes with numerous boundaries of the 3D models. In the proposed algorithm, our target BIM model is optimized with the Unity C# code based on triangle centroid concepts and classified using the KNN. As a result, the algorithm can check the number of mesh vertices and triangles before and after optimization of the entire model and each structure. In addition, it is able to optimize the mesh vertices of the original model by approximately 56 % and the triangles by about 42 %. Moreover, compared to the original model, the optimized model shows no visual differences in the model elements and information, meaning that high-performance visualization can be expected when using AR devices.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.113-114
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• 2022

가상의 공간에 실제의 설비를 구현하는 시뮬레이션 기술은 스마트팩토리를 구성하는 필수 요소 중의 하나이다. 다만, 현업의 제조 설비 도면을 시뮬레이션 소프트웨어에 적용하는데 있어 자유 곡선을 가지는 공압 배관 등의 모델 데이터는 작업의 난해함 등의 이유로 기 설계 도면에 누락되어 있는 경우가 빈번하다. 본 연구에서는 시뮬레이션 툴 중에 하나인 유니티를 이용하여 내부에서 직접 스윕 곡선을 생성하는 과정을 구현하였다. 이를 통해 기 설계 데이터에 누락된 다양한 자유 곡선 모델을 신속하게 시뮬레이션에 적용하는데 효과가 있을 것으로 기대된다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.73-74
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• 2019

증가하는 모바일 시장 규모에 맞추어 게임 엔진의 기능이 발전하고 있다. 대형 개발사를 위한 간편한 협업 기능부터 1인 개발자를 위한 간단한 기능들까지 다양한 기능들의 게임 엔진이 사용되고 있으며 그 중 유니티 엔진은 소규모 인디 개발자들을 위한 기능들을 많이 추가하고 또한 발전시켜 많은 개발자들에게 도움을 주고 있다. 본 논문 에서 소개하는 게임은 유니티의 여러 기능을 적극적으로 이용하고, 특히 네비메쉬 에이전트를 사용하여 사용자가 길 찾기 문제를 쉽게 하도록 만든 것이 특징이다.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4659-4663
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• 2023

The use of iodine S values derived using the International Commission Radiological Protection (ICRP) phantoms may introduce significant bias in internal dosimetry for Koreans due to anatomical variability. In the current study, we produced an extensive dataset of Korean S values for selected five iodine radioisotopes (I-125, I-129, I131, I-133, and I-134) for use in radiation protection. To calculate S values, we implemented Monte Carlo simulations using the Mesh-type Reference Korean Phantoms (MRKPs), developed in a high-quality/fidelity mesh format. Noticeable differences were observed in S value comparisons between the Korean and ICRP reference phantoms with ratios (Korean/ICRP) widely ranging from 0.16 to 6.2. The majority of S value ratios were lower than the unity in Korean phantoms (interquartile range = 0.47-1.28; mean = 0.96; median = 0.69). The S values provided in the current study will be extensively utilized in iodine internal dosimetry for Koreans.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.01a
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• pp.187-188
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• 2017

본 논문에서는 Inverse Kinematics(IK) 방법을 이용하여 사족보행 게임 캐릭터의 이동 IK를 구현하였다. 게임 캐릭터의 이동 IK는 Unity의 NavMeshAgent를 사용하여 이동하는 사족보행 생물체가 회전 시 척추를 자연스럽게 꺾이도록 구현되었다. 본 논문에서는 게임캐릭터에 이동 IK를 적용했을 때와 적용하지 않았을 때를 비교하였으며, 이동 IK를 적용한 경우에 경로를 따라 이동하는 사족보행 캐릭터의 애니메이션이 자연스럽게 이루어짐을 확인하였다.

• Journal of the Korea Society of Computer and Information
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• v.25 no.4
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• pp.55-61
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• 2020

In this paper, we present a novel approach to efficiently control the location of NPC(Non-playable characters) in the interactive virtual world such as game, virtual reality. To control the NPC's movement path, we first calculate the main trajectory based on the user's path, and then move the NPC based on the weight map. Our method constructs automatically a navigation mesh that provides new paths for NPC by referencing the user trajectories. Our method enables adaptive changes to the virtual world over time and provides user-preferred path weights for smartagent path planning. We have tested the usefulness of our algorithm with several example scenarios from interactive worlds such as video games, virtual reality. In practice, our framework can be applied easily to any type of navigation in an interactive world.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.1079-1081
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• 2021

Low-Poly는 비교적 적은 수의 Polygon을 가진 3D Computer Graphics의 Polygon Mesh이다. 본 논문의 VR·PC 기반 어드벤처 게임 '하늘섬의 비밀'에 이러한 Low-Poly 그래픽이 적용되어 비현실적이고 감성적인 스토리의 신비로운 분위기를 극대화 하는 효과를 발생시킨다. 또한 Low-Poly 그래픽은 VR 게임에서 현실과 가상세계를 구분하지 못해 생기는 괴리감과 이로 인해 오는 어지러움을 줄이고 사용자의 몰입도를 높여준다.

• Interaction and multiscale mechanics
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• v.3 no.3
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• pp.235-255
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• 2010

This paper investigates the heat equation for domains subjected to an internal source with a sharp spatial gradient. The solution is first approximated using linear finite elements, and sufficiently small time-step sizes to yield stable simulations. The main area of interest is then in the ability to approximate the solution using Generalized Finite Elements, and again explore the time-step limitations required for stable simulations. Both high order elements, as well as elements with special enrichments are used to generate solutions. When compared to linear finite elements, the high order elements deliver better accuracy at a given level of mesh refinement, but do not offer an increase in critical time-step size. When special enrichment functions are used, the solution can be approximated accurately on very coarse meshes, while yielding solutions which are both accurate and computationally efficient. The major conclusion of interest is that the significantly larger element size yields larger allowable time-step sizes while still maintaining stability of the time-stepping algorithm.