• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.184-188
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• 2006

Lightscape is a visual rendering software enabling higher dimensional 3D image production using rendering as well. However, direct light simulation showed that more realistic feature of material-specific texture or color could be achieved by adjusting options. Accordingly, this study is to generate optimal values of options and achieve more realistic images by varying such values according to individual materials in order to create better quality simulation images using Lightscape.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.238-246
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• 2018

The production of hyper-realistic digital rendering images has been available due to radical improvements of recent digital rendering and CGI (Computer-Generated Imagery) software technologies. The photorealism of digital architectural rendering images requires further studies and discussions in that architectural visualization becomes a foundation of other fields using digital rendering technology, such as movies, games, and VR industry. The principles for achieving photorealism on digital architectural rendering images were re-defined and detailed elements were analyzed through theoretical analysis of the former studies. Four principles were drawn from the architectural rendering images produced by newly-developed technologies: physically-accurate lighting calculations, accurate object geometry representation, realistic material and texture, and characteristics of photography. The sub-elements of those four principles are categorized into either essential or selective for photorealistic imagery and the randomness of the selective elements could explain the variety of photorealistic architectural rendering styles.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.4
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• pp.385-394
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• 1999

제품을 설계하는 디자이너나 엔지니어는 많은 시간과 노력을 들이지 않고서 그들이 설계한 3차원 제품 모델에 대한 사실적인 이미지를 원한다. 디자인 프로세스의 초기인 개념 설계에서부터 설계검증, 그리고 가공 과정에서 사실적인 이미지가 매우 유용하므로, 대부분의 주요 CAD 제작사는 그들의 CAD 소프트웨어에 고급 렌더링 기능을 추가하고 있다. 상용의 CAD/CAM 모델러에서는 NURB 곡면을 기초로 모델링을 수행하므로, NURB 곡면을 렌더링할 수 있는 패키지가 필요하다. VIF(Visual InterFace) 렌더링 라이브러리는 A-buffer 방식과 Ray tracing 방식의 두 가지 고급 렌더링 모드를 제공한다. 다각형은 물론 NURB 곡면을 입력으로 받아 사용자가 설정한 표면의 각종 계수, 원하는 view와 설정된 광원에 따라 이미지를 만들고 다양한 형태로 출력시킬 수 있는 다양한 기능을 제공한다. 본 논문에서는 VIF 렌더링 라이브러리에 대한 구조와 기능별로 분류된 함수에 대하여 설명하며, 실제로 CAD/CAM 시스템과 통합되어 구상설계에서부터 3차원 설계 모델링에 이르기까지의 제조공정에서 설계검증 툴로써 어떻게 활용되고 있는가에 대하여 기술한다.Abstract Engineers and industrial designers want to produce a realistic-looking images of a 3D model without spending a lot of time and money. Photo-realistic images are so useful from the conceptual design, through its verification, to the machining, that most major CAD venders offer built-in as well as add-on photo-realistic rendering capability to their core CAD software. Since 3D model is consists of a set of NURB surfaces in commercial CAD packages, we need a renderer which handles NURB surface as well as other primitives.A new rendering library called VIF (Visual InterFace) provides two photo-realistic rendering modes: A-buffer and Ray tracing. As an input data it takes NURB surfaces as well as polygonal data and produces images in accordance with the surface parameters, view and lights set by user and outputs image with different formats. This paper describes the overall architecture of VIF and its library functions classified by their functionalities, and discusses how VIF is used as a graphical verification tool in manufacturing processes from the conceptual design to 3D modeling.

• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.5
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• pp.75-83
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• 2019

Direct volume rendering is a widely used method for visualizing three-dimensional volume data such as medical images. This paper proposes a method for applying depth-of-field effects to volume ray-casting to enable more realistic depth-of-filed rendering in direct volume rendering. The proposed method exploits a camera model based on the human perceptual model and can obtain realistic images with a limited number of rays using jittered lens sampling. It also enables interactive exploration of volume data by on-the-fly calculating depth-of-field in the GPU pipeline without preprocessing. In the experiment with various data including medical images, we demonstrated that depth-of-field images with better depth perception were generated 2.6 to 4 times faster than the conventional method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.11
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• pp.1644-1652
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• 2022

In the case of safety training where practical training is impossible due to risk problems, training contents using realistic media such as virtual reality or augmented reality are becoming a new alternative. In this paper, we propose a smoke modeling method that can be applied to safety-training contents implemented with realistic media technology. When an accident occurs in a hazardous area such as a petrochemical plant, visibility is not secured due to gas leakage and fire. In order to create such a situation, it is important to realistically express smoke. The proposed method is a smoke model implementation technique that can be effectively applied to the background of complex passages and devices such as petrochemical plants. In the proposed method, the smoke is expressed using volumetric rendering in the post-processing stage for the resulting image of scene rendering. Implementation results in the background of the factory show that the proposed method produces models that can express the smoke realistically.

• International Journal of CAD/CAM
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• v.9 no.1
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• pp.79-83
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• 2010

Tidal bore is a peculiar nature phenomenon which is caused by the lunar and solar gravitation. Based on the physical characters of tidal bores, in this paper we propose a novel method to model and render this phenomenon, especially the tidal waves in Qiantang estuary. According to Boltzmann equation for tidal waves, we solve it with the novel triangle mesh of Kinectic Flux Vector Splitting (KFVS) mode. Then a method combining a curve forecasting wave and particles model is proposed to render the dynamic scenes of overturning tidal waves. Finally, with some rendering technologies, various realistic tidal waves under diversified conditions is rendered in real time.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.806-810
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• 2006

The research of computer graphics is divided into two parts of photorealistic rendering and non-photorealistic rendering. The purpose of non-photo realistic rendering is to make image like cartoon, water-color, hatching etc. In this paper, we study for real-time hatching rendering and shadow techniques and we combine two techniques to make real-time hatching shadow. In shadow techniques we apply projected texture shadow to hatching rendering. Eventually, we introduce natural real-time hatching shadow through comparison and analysis.

• Korean Journal of Computational Design and Engineering
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• v.13 no.6
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• pp.469-477
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• 2008

Physically-based rendering is an image synthesis technique based on simulation of physical interactions between light and surface materials. Since generated images are highly photorealistic, physically-based rendering has become an indispensable tool in advanced design visualization for manufacturing and architecture as well as in film VFX and animations. Especially, BRDF (bidirectional reflectance distribution function) is critical in realistic visualization of materials since it models how an incoming light is reflected on the surface in terms of intensity and outgoing angles. In this paper, we introduce techniques to represent BRDF as B-spline volumes and to utilize them in physically-based rendering. We show that B-spline volume BRDF (BVB) representation is suitable for measured BRDFs due to its compact size without quality loss in rendering. Moreover, various CAGD techniques can be applied to B-spline volume BRDFs for further controls such as refinement and blending.

• Journal of the Korea Computer Graphics Society
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• v.18 no.1
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• pp.11-21
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• 2012

Point-based rendering has gained much attention as an alternative to polygon-based rendering because of its simplicity and flexibility. However, current point-based rendering techniques do not provide a sufficient rendering quality for translucent materials such as human skin. In this paper, we propose a point-based rendering framework with subsurface scattering of light, which is important to create the soft and semi-translucent appearance of human skin. To accurately simulate subsurface scattering in multi-layer materials, we present splat-based diffusion to apply a linear combination of several Gaussian basis functions to each splat in object space. Compared to existing point-based approaches, our method offers a significantly improved visual quality in rendering human faces.

• Journal of Korea Multimedia Society
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• v.8 no.1
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• pp.88-100
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• 2005

In computer graphics, realistic skin rendering has been regarded as difficult tasks and remains as an important research subject. Translucent materials like skin have some complicated optical properties including subsurface scattering. In this paper, we proposes a skin shader based on subsurface scattering to render realistic skin and it has been implemented as a plug-in for Maya, 3D Package. The rendered image using this proposed skin shader appears more realistic than the rendered image using classical shading techniques. Furthermore, we could model sebum, epidermis, dermis using specular reflection, multiple scattering, single scattering respectively.