• Journal of Mechanical Science and Technology
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• v.14 no.10
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• pp.1104-1113
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• 2000

This paper proposes an efficient reverse engineering technique for compound surfaces using a boundary detection method. This approach consists in extracting geometric edge information using a vision system, which can be used in order to drastically reduce geometric errors in the vicinity of compound surface boundaries. Through the image-processing technique and the interpolation process, boundaries are reconstructed by either analytic curves (e. g. circle, ellipse, line) or parametric curves (B-spline curve). In other regions, except boundaries, geometric data are acquired on CMM as points inspected using a touch type probe, and then they are interpolated on several surfaces using a B-spline skinning method. Finally, the boundary edge and the skinned surfaces are combined to reconstruct the final compound surface. Through simulations and experimental works, the effectiveness of the proposed method is confirmed.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.5 s.98
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• pp.160-168
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• 1999

This paper describes one method of reverse engineering that machines a free form shape without descriptive model. A portable five-axes 3D CMM was used to digitize point data from physical model. After approximation by rational B-spline curve from digitized point data of a geometric shape, a surface was constructed by the skinning method of the cross-sectional design technique. Since a surface patch was segmented by fifteen part, surface merging was also implemented to assure the surface boundary continuity. Finally, composite surface was transferred to commercial CAD/CAM system through IFES translation in order to machine the modeled geometric shape.

• Cartoon and Animation Studies
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• s.44
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• pp.33-56
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• 2016

As the rapid extension of the game and film industry, studies on developing natural movements on a 3D characters are increasing. Rigging a character with joints is essential to create realistic movements on a 3D character. The rapid development of the CG industry, rigging technologies and workflow is becoming more sophisticated. Despite the progress and the growth of rigging operations, has shown the limitations of such repetitive tasks. For this study, analyzes the issues and inefficiency of the old method of skin weights and propose a better approach. First, need to understand the general process of an animation pipeline and learn the technology term of skin weights. Second, comparing the traditional ways of skinning a character and applying other deformers to work properly. Third, testing out new ways of weighting a character by applying deformers such as lattice and finally converting lattice weights back to skin weights. Forth, verifying effectiveness of the new method of skin weights by comparing with the traditional skin weighting process. The study shows that the new method of skin weights, reduced working hours and a better final weighting outcome. Expecting this study to enhance the method of skin weights and able to utilize this new skinning technology.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.567-572
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• 1988

As an efficient way of modeling bodies of complicated shapes, the sweeping and skinning operations have been implemented. These two operations are very powerful modeling method when the body is defined by the cross sections at various locations. For the implementation, the data structure for storing the cross sections and the resulting three dimensional body has been constructed. The resulting object is defined by the boundary representation based on the non-uniform nonperiodic B-spline surface.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.287-292
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• 2002

This paper presents a reverse engineering method for compound surfaces using vision system. A CNC machining center is used as a measuring station, which is equipped with slit beam generator and vision probe. Since obtained data using slit beam or laser scanner may have much data loss along the edge of compound surfaces, an algorithm is presented in this study to recover missing geometric data at such region. First, b-spline interpolation is applied to extract edge information of the surface, and as a next step, b-spline approximation is applied to recover the missing geometric data. Finally, b-spline skinning method is applied to regenerate the surface information. Appropriate simulation and experimental works are preformed to very the effectiveness of the proposed methods.

• Journal of information and communication convergence engineering
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• v.9 no.3
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• pp.266-270
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• 2011

The advancement of technology enables smart phones or handheld devices to render complex 3D graphics. However, the processing power and memory of smart phones remain very limited to render high polygon and details 3D models especially on games which requires animation, physic engine, or augmented reality. In this paper, several techniques will be introduced to speed up the computation and reducing the number of vertices of the 3D meshes without losing much detail.

• International Journal of Contents
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• v.3 no.4
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• pp.8-14
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• 2007

This study focuses on modeling mobile 3D game engine and suggesting modified skinned-mesh schema based on JSR-184 in order to improve the performance in terms of memory consumption and time complexity. Most of the 3D games have used OpenGL-ES low-level APls, which may limit portability and fast developing time. Hence, the 3D mobile game engine providing high-level APls which works on GSM (Global System for Mobile Communication) phones on J2ME, is proposed here in order to optimize the performance for Java environment abiding JSR-184 standard. To prove performance enhancement, skinned-mesh schema on JSR-184 engine is modified and tested. The experimental results are shown.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.45-46
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• 2013

대중에게 하나의 취미 생활로 자리매김한 게임은 특징이나 작동 방법에 따라 다양한 장르로 발전되었다. 그 중 액션게임 장르는 사용자가 조작하는 캐릭터의 역동적인 움직임과 움직임이 큰 동작으로 인해 사용자로 하여금 게임 플레이에 몰입할 수 있는 특징을 가지고 있다. 과거 2D 환경의 게임에서 연속되는 그림으로 표현되던 캐릭터의 애니메이션 장면은 3D 환경으로 발전하면서 새로운 애니메이션 기법을 필요로 하였으며, 현재 다양한 애니메이션 기법이 연구되고 있다. 본 논문에서는 3D 뼈대 애니메이션 통하여 DirectX에서의 캐릭터 애니메이션 적용 대해 설명한다.

• Journal of International Society for Simulation Surgery
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• v.2 no.2
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• pp.52-57
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• 2015

Virtual Reality makes a virtual environment more realistic and, furthermore, it provides a variety of experiences which we cannot have in reality. A drastic growth of GPU performance and increase of computing capability make virtual environment more realistic than ever. One important element of constructing virtual environment is to animate 3D characters. Many researchers have been studying 3D characters animating and a myriad of methods have been proposed to make them more realistic. In this paper, we discuss the technologies and characteristics of 3D character animation. We believe that realistic characters in Virtual Reality will be applied to various fields: education, film and game industry, business and, particularly, medical area such as telemedicine, virtual surgery, etc.

• Korean Journal of Computational Design and Engineering
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• v.4 no.1
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• pp.32-42
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• 1999

Approximate lofting or skinning is one of practical surface modeling techniques well used in CAD and reverse engineering applications. Presented in this paper is a method for approximately lofting a given set of curves wihin a specified tolereance. It is based on refitting input curves simultaneously on a common knot vector and interpolating them to get a resultant NURBS surface. A concept of reducing the number of interior knots of the common knot vector is well adopted to acquire more compact representation for the resultant surface. Energy minimization is newly introduced in curve refitting process to stabilize the solution of the fitting problem and get more fair curve. The proposed approximate lofting provides more smooth surface models and realizes more efficient data reduction expecially when the parameterization and compatibility of input curves are not good enough. The method has been successfully implemented in a new CAD/CAM product VX Vision? of Varimetrix Corporation.