会津大学＞Annual Review＞2002>Computer Graphics Laboratory

Annual Review 2002

Computer Graphics Laboratory

Gennadiy Nikishkov
Professor

Roman Durikovic
Assistant Professor

Computer Graphics Laboratory is concerned with physics based modeling of different phenomena, their visualization and animation. Created mathematical models are used for graphical representation of natural processes. This research includes modeling and visualization of deformable bodies and of flow of liquids. Examples of current research projects are: Physically based simulation and rendering of Japanese lacquer ware; Augmented reality interface; Computational modeling in nanomechanics.

Professors of the Computer Graphics Laboratory deliver courses in Computer Graphics, Numerical Analysis, Modeling and Visualization. The Laboratory is equipped with modern computers and editing devices. SCCP and Graduation projects are related to computer modeling, visualization and animation and to Web technologies.

Referred Journal Papers

[roman-01:2002]

R. Durikovic and S. Abe. Accelerated animation of liquid splash. Journal of Three Dimensional Images, 16(4):68-73, Dec 2002.
We present a method for simulation and visualization of a liquid splash motion. The proposed system is composed of a computational fluid dynamics and a polygon based renderer using multi texturing graphical acceleration. The system well supports the Navier-Stokes solver with adaptive time step and viscosity. The final liquid surface is obtained from the velocity field by rough estimation of the surface and then subdividing the surface. Rendering of the surface is performed by multi texturing method using the caustics, reflection, liquid and object textures.

[roman-02:2002]

R. Durikovic. Explicit method of sparkling effect simulation. Journal of Three Dimensional Images, 16(4):96-100, dec 2002.
We attempt to simulate the light reflection from the surfaces with inserted metallic flakes by explicit modeling of sparkle geometry. The light scattering within the system of metal particles creates the sparkling and glare effects with radial streaks of light around high intensity particles. Standard test between paint designers is to observe the paints with different spackle density on silver plates. First, we demonstrate the sparkling on plates for different statistical distributions of sparkles and finally we apply the technique on a very expensive kind of Japanese lacquer ware made by the nashiji technique.

Referred Proceeding Papers

[roman-03:2002]	R. Durikovic and S. Czanner. Implicit surfaces for dynamic growth of digestive system. In Proceedings of the Shape Modeling International, pages 111-117, Alberta, Canada, mar 2002. The embryologists found the realistic human organmodels and animations of development necessary for their studies. The aim of this paper is to present a methodology producing a realistic animations of development. The convolution surfaces generated by skeletons used for model representation are suitable for growth animation. The skeleton of a digestive system is a line skeleton with a tree structure. Therefore, its growth in length can be simulated by an algebraic L-system which controls the growth of skeleton segments. The global deformation of the skeleton due to the gravity and the lack of space in abdominal cavity are simulated by a dynamics of skeleton segments. The known movements are implemented in our model by external forces applied on links controlling the organ movement in space. The entire system consist of two steps: First, the actual number of skeleton segments and the length of each skeleton segment is calculated from growth functions, second, the skeleton deformation in space is updated based on dynamics.
[roman-04:2002]	R. Durikovic, K. Kolchin, and S. Ershov. Rendering of Japanese Artcraft. In I.N. Alvaro and Ph. Slusallek, editors, Proceedings of the EUROGRAPHICS short presentations, pages 131-138, Blackwell Publishers, UK, sep 2002. We present several methods for simulation of Japanese lacquer ware, a prominent Far East Asian handicraft art. We consider two most popular kinds of Japanese lacquer ware made by the makie and nashiji techniques. For rendering makie, we propose a method for preparing RGBA textures from digital photos of art items. The alpha channels of these textures control the weight with which color channels are blended with the measured biderectional releectance distribution function (BRDF) of a metallic finish. Both ray tracing and hardware based rendering are demonstrated. In the latter case, we show how the calculation of a sphere map texture used for BRDF visualization can be accelerated using a special coordinate system for tabulated BRDF. The depth effect manifested by nashiji lacquer is simulated by the explicit modeling of metal platelets immersed in absorptive material.
[roman-05:2002]	Y. Wakabayashi and R. Durikovic. Modeling bonsai trees using positional information. In Joint Convention Record of Tohoku Chapter of the Electrical and Information Engineers, page 341, No. 2I19, Yonezawa, Japan, 2002. The plants morphology models using formal languages or geometry were researched. However these models are not capable to control the form of plant, therefore we suggest the model of bonsai tree which is hard to model with previous methods. Up to now L-system are random generator in all branches were used to model trees and plants. Because L-system is deterministic systems, the overall silhouette of the tree and the plant is given and hard to control with input parameters. To model bonsai tree, we propose to use positional information of most important branches of the shape. From the measured data of selected branches, we can derive spline function approximating data which are used to write L-system. The L-system then reconstructs the tree skeleton with the same shape of spline function. This paper will focus on three essential elements, in particular: shape data acquisition and modeling curved limb explained in Section 2 and random distribution of small branches around the tree skeleton discussed Section 3.
[roman-06:2002]	S. Abe and R. Durikovic. Physically based water simulation and animation. In Joint Convention Record of Tohoku Chapter of the Electrical and Information Engineers, page 318, No. 2I13, Yonezawa, Japan, 2002. Physical based simulation and animation are playing an important role in the field of Computer Graphics (CG) in recent years. The improvements of physically based methods support CG-designers in producing realistic CG animation of natural phenomena; for example, rigid body collision, destruction of walls, fluid dynamics, steam and flames. Foster developed a modeling and controlling method of fluid dynamics. This method reduces simulation time costs and implements a high controllability of fluid. Kunimatsu and his group reduced rendering time cost to less than 60 seconds per frame. Their group utilized personal computer with graphics acceleration hardware. This paper will focus on a development of a real time system for realistic fluid animation, in particular the following features: 1) Dynamic fluid motion of mixture, splashinganb self-collision. 2) Realistic appearanceof refraction, reflection and caustics. 3) Real time simulation and animation.
[roman-07:2002]	R. Kimura, R. Durikovic, and K. Kolchin. Real-time rendering of Japanese lacquer ware. In Joint Convention Record of Tohoku Chapter of the Electrical and Information Engineers, page 316, No. 2I11, Yonezawa, Japan, 2002.
[roman-08:2002]	S. Katou and R. Durikovic. Image based rendering using HDR and Radiance. In Joint Convention Record of Tohoku Chapter of the Electrical and Information Engineers, page 319, No. 2I14, Yonezawa, Japan, 2002.
[roman-09:2002]	R. Durikovic and S. Abe. Accelerated animation of liquid splash. In Proceedings of the Human and Computer Conference - HC2002, pages 51-56, Aizu-Wakamatsu, Japan, sep 2002. We present a method for simulation and visualization of a liquid splash motion. The proposed system is composed of a computational fluid dynamics and a polygon based renderer using multi texturing graphical acceleration. The system well supports the Navier-Stokes solver with adaptive time step and viscosity. The final liquid surface is obtained from the velocity field by rough estimation of the surface and then subdividing the surface. Rendering of the surface is performed by multi texturing method using the caustics, re??ection, liquid and object textures.
[roman-10:2002]	R. Durikovic. Explicit method of sparkling effect simulation. In Proceedings of the Human and Computer Conference - HC2002, pages 87-91, Aizu-Wakamatsu, Japan, sep 2002. We attempt to simulate the light reflection from the surfaces with inserted metallic flakes by explicit modeling of sparkle geometry. The light scattering within the system of metal particles creates the sparkling and glare effects with radial streaks of light around high intensity particles. Standard test between paint designers is to observe the paints with di??erent spackle density on silver plates. First, we demonstrate the sparkling on plates for different statistical distributions of sparkles and finally we apply the technique on a very expensive kind of Japanese lacquer ware made by the nashiji technique.

Books

[roman-11:2002]

R. Durikovic and A. Belyaev. Proceedings of the Geometric Modeling, Computing, and Visualization. Technical Report 2003-1-004, The University of Aizu, Japan, jul 2003.

Chapters in Book

[niki-01:2002]

G.P.Nikishkov and S.N.Atluri. Combining SGBEM and FEM for modelling 3D cracks, page 26. Engineering Computational Technology. Saxe-Coburg, Stirling, Scotland, 2002.

Grants

[roman-12:2002]

R. Durikovic. Ministry of Education Scientific Research Fund, 2003-2004.

Academic Activities

[roman-13:2002]	Roman Durikovic, Apr. 2002. Organizing Committee Member, ACMSCCG 2002 Conference.
[roman-14:2002]	Roman Durikovic, Jul. 2002. Organizing Committee Member, EG and ACMGRAPHICON 2002 Conference.
[roman-15:2002]	Roman Durikovic, Nov. 2002. Committee Member, EGWSCG 2002 Conference.
[roman-16:2002]	Roman Durikovic, Sep. 2002. Committee Member, EUROGRAPHICS 2002 Conference.
[roman-17:2002]	Roman Durikovic, Jul. 2002. Committee Member, CGI 2002 Conference.

Ph.D and Other Thesis

[niki-02:2002]	Daijyu Matsushita. Generation and smooting of 2D triangular meshes, University of Aizu, 2003. Thesis Advisor: Nikishkov, G
[roman-18:2002]	Sayaka Endo. Graduation Thesis: Simulation of sparkles observed in lacquer-ware., University of Aizu, 2002. Thesis Advisor: Roman Durikovic.
[roman-19:2002]	Ken ichi Kamimura. Graduation Thesis: Hardware accelerated liquid visualization., University of Aizu, 2002. Thesis Advisor: Roman Durikovic.
[roman-20:2002]	Ryou Kimura. Graduation Thesis: Real-time rendering of Japanese lacquer-ware., University of Aizu, 2002. Thesis Advisor: Roman Durikovic.
[roman-21:2002]	Ryou Kimura. Graduation Thesis: Physical based simulation of soap bubble., University of Aizu, 2002. Thesis Advisor: Roman Durikovic.
[roman-22:2002]	Ryou Kimura. Master Thesis: Towards visual modeling of bonsai trees using biomechanical development., University of Aizu, 2002. Thesis Advisor: Roman Durikovic.