Research

My research interests are dynamic animation and realistic rendering of hair. I am focusing mainly on real-time methods and possible use of programmable graphics hardware in such methods. This page gives an overview of some of the papers concerning these topics. It does not include latest work and is due for an update in a decade or so ;-)

Publications

• Kadleček, P., Kmoch, P. and Křivánek, J. Haptic rendering for under-actuated 6/3-DOF haptic devices. Proceedings of EuroHaptics 2014, Springer, 2014.
• Kmoch, P., Bonanni, U. and Pelikán, J. Towards a GPU-Only Rod-Based Hair Animation System. Siggraph Asia 2010 Technical Sketches and Posters, ACM, 2010.
• Elek, O. and Kmoch, P. Real-Time Spectral Scattering in Large-Scale Natural Participating Media. Proceedings of SCCG 2010, Comenius University, Bratislava, 2010.
• Bonanni, U., Kmoch, P. and Magnenat-Thalmann, N. Interaction Metaphors for Modeling Hair using Haptic Interfaces. International Journal of CAD/CAM, Society of CAD/CAM Engineers, 2009.
• Bonanni, U., Kmoch, P. and Magnenat-Thalmann, N. Tool-based Hairstyling Metaphors. Proceedings of IEEE CAD/Graphics 2009, IEEE Computer Society Press, 2009.
• Bonanni, U., Kmoch, P. and Magnenat-Thalmann, N. Haptic Interaction with One-Dimensional Structures. Proceedings of ACM VRST 2009, ACM, 2009.
• Kmoch, P., Bonanni, U. and Magnenat-Thalmann, N. Hair Simulation Model for Real-Time Environments. Proceedings of CGI 2009, ACM, 2009.
• Bonanni, U. and Kmoch, P. Virtual Hair Handle: A Model for Haptic Hairstyling. Eurographics 2008 - Short Papers (eds. K. Mania, E. Reinhard), pp. 135–138, Eurographics Association, Crete, Greece, 2008, ISSN 1017-4656. Available from download section.
• Kmoch, P. Hair Animation Methods. WDS'07 Proceedings of Contributed Papers: Part I—Mathematics and Computer Sciences, Matfyzpress, 2007.
• Kmoch, P. Impostors and Interiors in Virtual old Prague. MIS 2007, Matfyzpress, 2007.
• Kmoch, P. Exteriors and interiors in virtual cities. Master thesis, MFF UK, 2006. Available from download section.

References

Hair animation and rendering

• Y. Bando, B.-Y. Chen, T. Nishita. Animating Hair with Loosely Connected Particles. Computer Graphics Forum (Eurographics 2003 Proc.), Volume 22, Issue 3. Available from author's website.
  Hair represented by particles. Springs connect particles close to each other at original rest position. Hair-hair interaction solved as pressure in particle hydrodynamics. Air integrated as second, interconnected particle system. Hair visualized by texture splatting.
• Bertails, F., Kim, T., Cani, M., Neumann, U. Adaptive Wisp Tree: a multiresolution control structure for simulating dynamic clustering in hair motion. In Proceedings of the 2003 ACM Siggraph/Eurographics Symposium on Computer Animation (San Diego, California, July 26–27, 2003), p. 207–213. Available from ACM digital library.
  Definition of Adaptive wisp tree, a control structure for dynamic hair clustering. It cooperates with geometric wisp representation, governing when wisp merging is possible, based on relative speed and orientation. Collisions are handled using bounding cylinders of the wisp tree.
• Bertails, F., Ménier, C., and Cani, M. A practical self-shadowing algorithm for interactive hair animation. In Proceedings of the 2005 Conference on Graphics interface (Victoria, British Columbia, May 09–11, 2005),ACM International Conference Proceeding Series, vol. 112, p. 71-–78. Available from ACM digital library.
  Definition of 3D light-oriented shadow map, a data structure for accelerating collision handling and self-shadow computation. It is a voxel grid oriented in the direction of light rays. Each voxel holds hair density, which is used to compute progressive shadowing. If the hair density exceeds a threshold, wisps are expelled from it to simulate collision.
• R. Gupta, N. Magnenat Thalmann. Scattering-Based Interactive Hair Rendering. Internatinal Conference on CAD/Graphics, IEEE Computer Society Press, p. 489–494. December 2005. Available from MIRALab website.
  Interactive shadow computation added to Animating Complex Hairstyles in Real-Time. Lattice cells hold pre-computed hair volume, which is used for shadow computation and updated each frame based on lattice movement.
• S. Hadap, N. Magnenat-Thalmann. Modeling Dynamic Hair as a Continuum. Computer Graphics Forum, Volume 20, Issue 3, Eurographics Proceedings, Manchester, United Kingdom, pp. 329–338. September, 2001. Available from MIRALab website.
  Hair represented both as a continuum, via particles, and as serial mutli-body chains. Hair-hair interaction solved via particle dynamics. Particles are bound to hair strands and exert forces on them. Air is integrated as a second, interconnected particle system.
• Kajiya, J. T., Kay, T. L. Rendering fur with three dimensional textures. In Proceedings of the 16th Annual Conference on Computer Graphics and interactive Techniques SIGGRAPH '89, p. 271–280. Available from ACM digital library.
  Definition of new graphic primitive, "texel", for fur rendering. Most important point: contains definition of lighting model for hair widely adopted since.
• M. Koster, J. Haber, H. Seidel. Real-time rendering of human hair using programmable graphics hardware. In Proceedings of Computer Graphics International 2004 (CGI 2004), June 2004. Available from author's website.
  Real-time method. Represents hair wisps as textured triangle strips. Hair can be curly as well. Utilizes programmable GPUs. Shadows are computed using opacity shadow maps.
• Liang, W., Huang, Z. An Enhanced Framework for Real-Time Hair Animation. 11th Pacific Conference on Computer Graphics and Applications (PG'03), p. 467, 2003. Available from IEEE digital library.
  Real-time method. Represents hair as textured triangle strips. To improve voluemtric appearance of hair, the strips are bent into U-shape and connected to the scalp.
• Marschner, S. R., Jensen, H. W., Cammarano, M., Worley, S., Hanrahan, P. Light scattering from human hair fibers. ACM Trans. Graph. 22, 3 (Jul. 2003), p. 780–791. Available from ACM digital library.
  Critique of lighting model widely used for hair. Introduces a new, more realistic model based on detailed scattering measurements.
• P. Volino, N. Magnenat-Thalmann. Animating Complex Hairstyles in Real-Time. VRST 2004, p. 41–48, November 2004. Available from MIRALab website.
  Real-time method. Hair is animated using a free-form deformation lattice. Hair is attached to the lattice via viscoelastic forces. The lattice is animated as a particle system. Hair-body collision is handled using metaballs. For rendering, the final position of a hair strand is interpolated from its displacement caused by head motion and displacement caused by the lattice. To make the deformation less uniform, strands are offset slightly for the purpose of lattice binding.
• Ward, K., Lin, M. C. Adaptive Grouping and Subdivision for Simulating Hair Dynamics. 11th Pacific Conference on Computer Graphics and Applications (PG'03), p. 234, 2003. Available from IEEE digital library.
  Level-of-detail approach in physical simulation of hair. Uses three primitive types: strads, wisps and strips. Each of these has its own discrete LOD hierarchy. All are animated based on the same kind of skeleton. Transition between LODs depends on visibility, speed and viewing distance.

Particle systems

• M. Desbrun, M.-P. Gascuel. Smoothed Particles: A new paradigm for animating highly deformable bodies. Proceedings of Eurographics Workshop on Computer Animation and Simulation '96, 61-76, 1996. Available from author's website.
  Introducing smoothed particle hydrodynamics into computer graphics. Particles serve as sampling points for a continuous field, moving along with its flow.
• Reeves, W. T. Particle systems—a technique for modeling a class of fuzzy objects. In Proceedings of the 10th Annual Conference on Computer Graphics and interactive Techniques (Detroit, Michigan, United States, July 25–29, 1983). Available from ACM digital library.
  Definition of a particle system.