• Proceedings of the IEEK Conference
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• 2000.11c
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• pp.109-112
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• 2000

Many applications in computer graphics require highly detailed complex models. However, the level of detail may vary considerably according to applications. It is often desirable to use approximations in place of excessively detailed models. We have developed a surface simplification algorithm which uses iterative contractions of edges to simplify models and maintains surface error approximations using a quadric metric. In this paper, we present an improved quadric error metric for simplifying meshes. The new metric, based on subdivided edge classification, results in more accurate simplified meshes. We show that a subdivided edge classification captures discontinuities efficiently. The new scheme is demonstrated on a variety of meshes.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.12
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• pp.1633-1638
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• 1988

This paper proposes the lattice-structured space subdivision method using bounding volume to reduce a great number of ray-surface intersection calculations in ray tracing algorithm for the computer graphics. We show that this method reduced 50%-70% calculations compard to pre-exist method by experiments.

• Journal of the Korea Society for Simulation
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• v.6 no.1
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• pp.61-69
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• 1997

In 3D computer graphics, fractal techniques have been applied to terrain models. Even though fractal models are convenient way to get the data of terrain models, it is not easy to gain the final results by manipulating the data of terrain model. However, by using the object oriented programming techniques, we could reduce the effort of programming job to find the final result. In this paper, a set of classes made by object oriented programming technique is presented. To show the results, the data of a terrain model were made by a fractal technique, namely, the midpoint displacement methods with square lattices of points.

• The Journal of the Korea Contents Association
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• v.10 no.8
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• pp.119-129
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• 2010

Recently, development of mobile service and increased demand for mobile device make mobile environment noticeable in computer graphics. Especially demand for 3D graphic services in mobile devices is steadily increased. However up to the present non-photorealistic rendering is mainly studied in desktop platform. In the result, existing research were designed for desktop computers and are not well-suited for mobile devices. Thus, there is a growing needs for processing techniques that provide the ability to render 3D non-photorealistic graphics through mobile devices. In this paper, we discuss processing techniques for non-photorealistic rendering that are especially cartoon shading and rendering in mobile devices. Through the result of this research, it is expected that silhouette edge rendering for mobile display environment and preprocessing file technique for shading. The efficiency of 3D mobile graphic service like 3D model in cartoon style is increased by using proposed preprocessing file and rendering pipeline. Our work can provide mobile cartoon rendering results and various mobile contents to users.

• Journal of the Korea Computer Graphics Society
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• v.22 no.5
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• pp.17-26
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• 2016

This paper presents an adaptive slicing method based on merging vertical layer polylines. Firstly, we slice the input 3D polygon model uniformly with the minimum printable thickness, which results in bounding polylines of the cross section at each layer. Next, we group a set of layer polylines according to vertical connectivity. We then remove polylines in overdense area of each group. The number of layers to merge is determined by the layer thickness computed using the cusp height of the layer. A set of layer polylines are merged into a single polyline by removing the polylines within the layer thickness. The proposed method maintains the shape features as well as reduces the printing time. For evaluation, we sliced ten 3D polygon models using our method and a global adaptive slicing method and measured the total length of polylines which determines the printing time. The result showed that the total length from our method was shorter than the other method for all ten models, which meant that our method achieved less printing time.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.669-672
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• 2003

3D object recognition is difficult but important in computer vision. The important thing is to understand about the relationship between a geometric structure in three dimensions and its image projection. Most 3D recognition systems construct models either manually or by training the pose and orientation of the objects. But both approaches are not satisfactory. In this paper, we focus on a commercial CAD model as a third type of model building for vision. The models are expressed in Initial Graphics Exchanges Specification(IGES) output and reconstructed in a pinhole camera coordinate.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.4
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• pp.181-187
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• 2001

본 논문에서는 3D 텍스쳐 매핑 하드웨어(texture mapping hardware)하에서 OpenGL를 이용하여 빠른 추출(classification) 및 음영처리(shading)를 가능하게 하는 직접 볼륨 렌더링(direct volume rendering) 방법을 제안한다. 추출과정을 위해 lookup table을 통해서 볼륨 데이터의 밀도값(density)으로부터 불투명도(opacity)값을 얻어내고, 법선 벡터 블렌딩(normal blending)방법을 제안하여 볼륨 크기에 상관없이 최종 이미지에서만 음영 처리 연산을 수행한다. 본 논문에서 제시된 볼륨 렌더링의 전과정이 그래픽스 하드웨어(graphics hardware)에서 이뤄지면, 음영처리 연산의 복잡도 감소로 인하여 상호 대화적인 볼륨 렌더링이 가능하다.

• Proceedings of the IEEK Conference
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• 2000.11c
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• pp.169-172
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• 2000

Recently, the advent of World-Wide-Web(WWW) and the explosive popularity of the Internet gave birth to collaborative applications which were enabled by computers and networks as their primary media. And the progress of 3D computer graphics enabled collaborative application with 3D virtual environments or distributed virtual environments. In this paper, we explain our implementation of Share collaboration engine and Virtual Architectural Engineering 2000 (VAE2000) system which is our pilot application implemented with Share collaboration engine. And we explain problems presented by our experiments with VAE2000 system. For those problems, we design our new middle-ware system, SHINE(SHared INternet Environment). The SHINE proposes new concepts and approaches for collaboration with 3D objects in a virtual world.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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• pp.201-206
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• 1999

Though a demand for 3-D CG (Three-Dimensional Computer Graphics) drastically increases, traditional modeling system for virtual objects are very difficult to handle. Applying VR (Virtual Reality) technology is, however, able to make the modeling systems more efficiently and intuitively. In this paper, traditional modeling operations are analyzed and their problems are clarified. We discuss what can be improved with VR technology. Then, a guideline of merging VR technology into the modeling system is described. A new modeling system is proposed using a CAVE system which is utilized in the latest VR technology. This proposed system aids in creating 3-D objects with high immersion in VEs (Virtual Environments)

• Journal of Korea Multimedia Society
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• v.10 no.10
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• pp.1310-1318
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• 2007

First of all, What was the modeling technique used to model 3D-Game character? It's a technique developed along several years, by experience... here is the bases Low polygons characters I always work in low polygon for two reasons -You can easily modify a low-poly character, change shapes, make morph for facial expressions etc -You can easily animate a low-poly character When the modeling is finished, Second, In these days, Computer hardware technologies have been bring about that expansion of various 3D digital motion pictured information and development. 3D digital techniques can be used to be diversity in Animation, Virtual-Reality, Movie, Advertisement, Game and so on. Besides, as computing power has been better and higher, the development of 3D Animations and Character are required gradually. In order to satisfy the requirement, Research about how to make 3D Game modeling that represents Character's emotions, sensibilities, is beginning to set its appearance. 3D characters in 3D Games are the core for the communications of emotion and the informations through their facial expression and characteristic motions, Sounds to Users. All concerning about 3D motion and facial expression are getting higher with extension of frequency in use. Therefore, in this study we suggest the effective method of modeling for 3D character and which are based on 2D Graphics.