Gennadiy Nikishkov
Professor
Pierre-Alain Fayolle
Assistant Professor
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Gennadiy Nikishkov Professor |
Pierre-Alain Fayolle Assistant Professor |
The Computer Graphics Lab conducts research into physics-based modeling of different phenomena, their visualization and animation. Innovative approaches to graphical user interfaces and direct interaction methods, modeling, rendering, simulation and scientific visualization are under development. Created mathematical models are used for graphical representation of natural processes.
Research areas include:
Visualization of surface and volume data, which results from finite element, boundary element and finite difference modeling.
Nanomechanics modeling. Finite element and molecular mechanics modeling of self-positioning micro- and nanostructures.
Augmented reality interface for different fields of human activity.
Using graphics processing units for physics-based modeling and animation.
Development of algorithms for shape modeling, analysis and understanding (operations on shape, segmentation and reconstruction).
Investigation of algorithms for the polygonization of implicit surfaces (adaptative and robust polygonization, fast polygonization).
Professors of the Computer Graphics Laboratory deliver courses in Computer Graphics, Numerical Analysis, Modeling and Visualization. Graduation projects are related to computer graphics, human-computer interaction, physics-based modeling, visualization, and animation.
O. Fryazinov, P.-A. Fayolle, T. Vilbrandt, G. Pasko, and A. Pasko. Feature based volumes for implicit intersections. Computer & Graphics, 35(3):524 531, 2011.
The automatic generation of volumes bounding the intersection of two implicit surfaces (isosurfaces of real functions of 3D point coordinates) or feature based volumes (FBV) is presented. Such FBVs are defined by constructive operations, function normalization and offsetting. By applying various offset operations to the intersection of two surfaces, we can obtain variations in the shape of an FBV. The resulting volume can be used as a boundary for blending operations applied to two corresponding volumes, and also for visualization of feature curves and modeling of surface based structures including microstructures.
A. Pasko, O. Fryazinov, T. Vilbrandt, P.-A. Fayolle P.-A., and V. Adzhiev. Procedural function-based modeling of volumetric microstructures. Graphical Models, 73(5):165-181, 2011.
We propose a new approach to modelling heterogeneous objects containing internal volumetric structures with size of details orders of magnitude smaller than the overall size of the object. The proposed function-based procedural representation provides compact, precise, and arbitrarily parametrised models of coherent microstructures, which can undergo blending, deformations, and other geometric operations, and can be directly rendered and fabricated without generating any auxiliary representations (such as polygonalmeshes and voxel arrays). In particular,modelling of regular lattices and cellular microstructures as well as irregular porous media is discussed and illustrated. We also present a method to estimate parameters of the given model by fitting it to microstructure data obtained with magnetic resonance imaging and other measurements of natural and artificial objects. Examples of rendering and digital fabrication of microstructure models are presented.
Jai Hak Park, Maan Won Kim, and Gennadiy Nikishkov. SGBEM-FEM alternating method for simulating 3D through-thickness crack growth. Computer Modeling in Engineering and Sciences, 68:269-295, 2010.
A SGBEM-FEM alternating method had been proposed by Nikishkov, Park and Atluri for the analysis of three-dimensional planar and non-planar cracks and their growth. In the method, the symmetric Galerkin boundary element method is used for the crack solution in an infinite body and the finite element method is used to perform stress analysis for the uncracked body only. In this paper the method is extended further to analyze through-thickness cracks. Adequate shape of boundary element mesh is examined and it is found that the fictitious portion of the boundary element mesh, which is located outside the body, plays an important role in the method. In order to check the accuracy and efficiency of the method, the obtained stress intensity factors are compared with the known solutions or the results obtained from finite element method. Using the proposed method stress corrosion crack growth simulation is performed for a through-thickness crack with unequal surface lengths.
J.H.Park and G.P.Nikishkov. Examination and improvement of accuracy of three-dimensional elastic crack solutions obtained using finite element alternating method. Transactions of the Korean Society of Mechanical Engineers, A34:629-635, 2010.
An SGBEM (symmetric Galerkin boundary element method)-FEM alternating method has been proposed by Nikishkov, Park and Atluri. This method can be used to obtain mixed-mode stress intensity factors for planar and nonplanar three-dimensional cracks having an arbitrary shape. For field applications, however, it is necessary to verify the accuracy and consistency of this method. Therefore, in this study, we investigate the effects of several factors on the accuracy of the stress intensity factors obtained using the abovementioned alternating method. The obtained stress intensity factors are compared with the known values provided in handbooks, especially in the case of internal and external circumferential semi-elliptical surface cracks. The results show that the SGBEM-FEM alternating method yields accurate stress intensity factors for three-dimensional cracks, including internal and external circumferential surface cracks and that the method can be used as a robust crack analysis tool for solving field problems.
P.-A. Fayolle and A. Pasko. Distance to Objects Built with Set Operations in Constructive Solid Modeling. In Proceedings of the 13th international conference on Humans and Computers, pages 41-46, 2011.
We present in this paper methods to compute the signed Euclidean distance to surfaces obtained by the intersection (respectively union or difference) of two solids (in two or three dimensions). These implementations can replace min/max or R-functions traditionally used to model set operations used with implicit surfaces.
O. Fryazinov, P.-A. Fayolle, T. Vilbrandt, G. Pasko, and A. Pasko. Feature based volumes for implicit intersections. In Proceedings of SMI 11, doi 10.1016/j.cag.2011.03.029, 2011.
The automatic generation of volumes bounding the intersection of two implicit surfaces (isosurfaces of real functions of 3D point coordinates) or feature based volumes (FBV) is presented. Such FBVs are defined by constructive operations, function normalization and offsetting. By applying various offset operations to the intersection of two surfaces, we can obtain variations in the shape of an FBV. The resulting volume can be used as a boundary for blending operations applied to two corresponding volumes, and also for visualization of feature curves and modeling of surface based structures including microstructures.
G. P. Nikishkov. Modeling of 3D SCC Crack Growth with SGBEM-FEM Alternating Method. In Joint Int. Conf. on Supercomputing in Nuclear Applications and Monte Carlo 2010 (SNA + MC2010), page 4 pp., Tokyo, Japan, 17-21 October 2010.
The paper presents a computational procedure for modeling SCC (stress corrosion cracking) crack growth for three-dimensional cracks in structural components. A structural component without a crack is modeled by the finite element method (FEM) and a crack is simulated with the symmetric Galerkin boundary element method (SGBEM). Separate modeling of the structural component and the crack with subsequent superposition helps to avoid complications related to modification of a mesh in the case of pure finite element modeling. The crack growth rate is determined by the SCC material model based on the effective stress intensity factor. For an arbitrary threedimensional crack the effective stress intensity factor is calculated through the value of the J-integral. It is supposed that the crack growth direction coincides with the J-integral vector. Results of SCC crack growth for three-dimensional semi-elliptical cracks are presented.
Gennadiy Nikishkov. Tohoku Nuclear Cluster, 2010.
P.-A. Fayolle, 2011.
Reviewer for CGI 2011
P.-A. Fayolle, 2011.
Reviewer for Engineering with Computers
P.-A. Fayolle, 2011.
Reviewer for SMI 2011
P.-A. Fayolle, 2010.
Reviewer for IJCGT
P.-A. Fayolle, 2010.
Reviewer for SCCG 2010
Gennadiy Nikishkov, 2010.
Member of the Editorial Board, International Journal 'Computer Modeling in Engineering and Sciences'.
Gennadiy Nikishkov, May 2010.
Member of the Program Committee, Int. Conf. on Computer Graphics Theory and Applications GRAPP 2010, Angers, France.
Gennadiy Nikishkov, June 2010.
Member of the Program Committee, The 10th IEEE International Conference on Computer and Information Technology (CIT 2010), Bradford, UK.
Gennadiy Nikishkov, September 2010.
Member of the Editorial Board, The Tenth International Conference on Computational Structures Technology CST 2010, Valencia, Spain.
Gennadiy Nikishkov, February 2011.
Member of the Program Committee, IASTED International Conference on Computer Graphics and Imaging (CGIM 2011), Innsbruck, Austria.
Gennadiy Nikishkov, 2010.
Reviewer, Computer Modeling in Engineering and Sciences.
Yuichi Sugawara. Graduation Thesis: Animation of robot movement, School of Computer Science and Engineering, March 2011.
Thesis Adviser: Gennadiy Nikishkov
Daichi Hirose. Graduation Thesis: Virtual try-on system for eyeglasses, School of Computer Science and Engineering, March 2011.
Thesis Adviser: Gennadiy Nikishkov
Yujiro Aoyagi. Graduation Thesis: Using Wii remote for augmented reality, School of Computer Science and Engineering, March 2011.
Thesis Adviser: Gennadiy Nikishkov
Junya Hayakawa. Graduation Thesis: Particle simulation using CUDA, School of Computer Science and Engineering, March 2011.
Thesis Adviser: Gennadiy Nikishkov
Toru Morizane. Graduation Thesis: Solution of Laplace/Poisson equation using CUDA, University of Aizu, 2011.
Thesis Adviser: Gennadiy Nikishkov
Masahiro Hoshi. Graduation Thesis: Three-dimensional graphics on Android device, University of Aizu, 2011.
Thesis Adviser: Gennadiy Nikishkov
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