The Visual Computer

, Volume 22, Issue 9–11, pp 785–792 | Cite as

Interactive ray tracing of skinned animations

  • Johannes Günther
  • Heiko Friedrich
  • Hans-Peter Seidel
  • Philipp Slusallek
Special Issue Paper


Recent high-performance ray tracing implementations have already achieved interactive performance on a single PC even for highly complex scenes. However, so far these approaches have been limited to mostly static scenes due to the high cost of updating the necessary spatial index structures after modifying scene geometry. In this paper, we present an approach that avoids these updates almost completely for the case of skinned models as typically used in computer games. We assume that the characters are built from meshes with an underlying skeleton structure, where the set of joint angles defines the character’s pose and determines the skinning parameters. Based on a sampling of the possible pose space we build a static fuzzy kd-tree for each skeleton segment in a fast preprocessing step. This fuzzy kd-tree is then organized into a top-level kd-tree. Together with the skeleton’s affine transformations this multi-level kd-tree allows fast and efficient scene traversal at runtime, while arbitrary combinations of animation sequences can be applied interactively to the joint angles. We achieve a real-time ray tracing performance of up to 15 frames per second at 1024×1024 resolution even on a single processor core.


Ray tracing Fuzzy kd-tree Dynamic scenes 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Supplementary material

371_2006_63_MOESM1_ESM.avi (19.5 mb)
Movie 1 21MB


  1. 1.
    Amanatides, J., Woo, A.: A fast voxel traversal algorithm for ray tracing. In: Proceedings of Eurographics, pp. 3–10. Eurographics Association (1987)Google Scholar
  2. 2.
    Appel, A.: Some techniques for shading machine renderings of solids. In: AF/PS Conference Proceedings (Springer Joint Computer Conference), vol. 32, pp. 37–45. Thompson Book Company, Washington, DC (1968)Google Scholar
  3. 3.
    ATI: The ATI homepage. Scholar
  4. 4.
    Cal3D: 3D character animation library. Scholar
  5. 5.
    Carr, N.A., Hoberock, J., Crane, K., Hart, J.C.: Fast GPU ray tracing of dynamic meshes using geometry images. In: Proceedings of Graphics Interface. A.K. Peters, Wellesley, MA (2006)Google Scholar
  6. 6.
    Cleary, J., Wyvill, B., Birtwistle, G., Vatti, R.: A parallel ray tracing computer. In: Proceedings of the Association of Simula Users Conference, pp. 77–80. Canadian Information Processing Society, Mississauge, ON (1983)Google Scholar
  7. 7.
    Foley, T., Sugerman, J.: KD-tree acceleration structures for a GPU raytracer. In: HWWS ’05 Proceedings, pp. 15–22. ACM Press, New York (2005)CrossRefGoogle Scholar
  8. 8.
    Glassner, A.S.: Space subdivision for fast ray tracing. IEEE Comput. Graph. Appl. 4(10), 15–22 (1984)Google Scholar
  9. 9.
    Goodnight, N., Wang, R., Woolley, C., Humphreys, G.: Interactive time-dependent tone mapping using programmable graphics hardware. In: P.H. Christensen, D. Cohen-Or (eds.) Proceedings of the 2003 Eurographics Symposium on Rendering, pp. 26–37. Eurographics Association, Aire-la-Ville, Switzerland (2003)Google Scholar
  10. 10.
    Günther, J., Friedrich, H., Wald, I., Seidel, H.P., Slusallek, P.: Ray tracing animated scenes using motion decomposition. Comput. Graph. Forum 25(3) (2006). (Proceedings of Eurographics) (to appear, preprint available at∼guenther/modecomp/)Google Scholar
  11. 11.
    Havran, V.: Heuristic Ray Shooting Algorithms. Ph.D. thesis, Faculty of Electrical Engineering, Czech Technical University in Prague (2001)Google Scholar
  12. 12.
    Havran, V., Prikryl, J., Purgathofer, W.: Statistical comparison of ray-shooting efficiency schemes. Tech. Rep. TR-186-2-00-14, Department of Computer Science, Czech Technical University; Vienna University of Technology (2000)Google Scholar
  13. 13.
    Intel Corp.: Intel Pentium III Streaming SIMD Extensions. (2002)Google Scholar
  14. 14.
    Jansen, F.W.: Data structures for ray tracing. In: Proceedings of the Workshop on Data structures for Raster Graphics, pp. 57–73. Springer, New York, NY (1986)Google Scholar
  15. 15.
    Lauterbach, C., Yoon, S.E., Tuft, D., Manocha, D.: RT-DEFORM Interactive Ray tracing of dynamic scenes using BVHs. Technical Report TR06-010, Department of Computer Science University of North Carolina (2006)Google Scholar
  16. 16.
    Lext, J., Akenine-Möller, T.: Towards rapid reconstruction for animated ray tracing. In: Eurographics 2001 – Short Presentations, pp. 311–318 (2001)Google Scholar
  17. 17.
    Lext, J., Assarsson, U., Möller, T.: BART: A benchmark for animated ray tracing. Tech. Rep., Department of Computer Engineering, Chalmers University of Technology, Göteborg, Sweden (2000)Google Scholar
  18. 18.
    MacDonald, J.D., Booth, K.S.: Heuristics for ray tracing using space subdivision. In: Proceedings of Graphics Interface, pp. 152–63. A.K. Peters, Wellesley, MA (1989)Google Scholar
  19. 19.
    Magnenat-Thalmann, N., Laperrière, R., Thalmann, D.: Joint-dependent local deformations for hand animation and object grasping. In: Proceedings of Graphics Interface ’88, pp. 26–33. Canadian Information Processing Society, Toronto, Ont., Canada (1988)Google Scholar
  20. 20.
    Magnenat-Thalmann, N., Thalmann, D.: Human body deformations using joint-dependent local operators and finite-element theory, pp. 243–262. Morgan Kaufmann, San Francisco, CA (1991)Google Scholar
  21. 21.
    Pharr, M., Humphreys, G.: Physically Based Rendering: From Theory to Implementation. Morgan Kaufman, San Francisco, CA (2004)Google Scholar
  22. 22.
    Reinhard, E., Smits, B., Hansen, C.: Dynamic acceleration structures for interactive ray tracing. In: Proceedings of the Eurographics Workshop on Rendering, pp. 299–306. Brno, Czech Republic (2000)Google Scholar
  23. 23.
    Reshetov, A., Soupikov, A., Hurley, J.: Multi-level ray tracing algorithm. ACM Trans. Graph. 24(3), 1176–1185 (2005)CrossRefGoogle Scholar
  24. 24.
    Rubin, S.M., Whitted, T.: A three-dimensional representation for fast rendering of complex scenes. Comput. Graph. 14(3), 110–116 (1980)CrossRefGoogle Scholar
  25. 25.
    Schmittler, J., Wald, I., Slusallek, P.: SaarCOR – A hardware architecture for ray tracing. In: Proceedings of the ACM SIGGRAPH/Eurographics Conference on Graphics Hardware, pp. 27–36 (2002)Google Scholar
  26. 26.
    Wächter, C., Keller, A.: Instant ray tracing: The bounding interval hierarchy. In: Rendering Techniques 2006, Proceedings of the Eurographics Symposium on Rendering (2006)Google Scholar
  27. 27.
    Wald, I.: Realtime Ray Tracing and Interactive Global Illumination. Ph.D. thesis, Computer Graphics Group, Saarland University (2004)Google Scholar
  28. 28.
    Wald, I., Benthin, C., Slusallek, P.: Distributed interactive ray tracing of dynamic scenes. In: Proceedings of the IEEE Symposium on Parallel and Large-Data Visualization and Graphics (PVG), pp. 77–86 (2003)Google Scholar
  29. 29.
    Wald, I., Boulos, S., Shirley, P.: Ray tracing deformable scenes using dynamic bounding volume hierarchies. SCI Institute Technical Report UUSCI-2006-015, University of Utah (2006)Google Scholar
  30. 30.
    Wald, I., Havran, V.: On building fast kd-trees for ray tracing, and on doing that in O(NlogN). In: Proceedings of the 2006 IEEE Symposium on Interactive Ray Tracing (2006)Google Scholar
  31. 31.
    Wald, I., Ize, T., Kensler, A., Knoll, A., Parker, S.G.: Ray tracing animated scenes using coherent grid traversal. ACM Trans. Graph. 25(3), 485–493 (2006)CrossRefGoogle Scholar
  32. 32.
    Wald, I., Slusallek, P., Benthin, C., Wagner, M.: Interactive rendering with coherent ray tracing. Comput. Graph. Forum 20(3), 153–164 (2001)CrossRefGoogle Scholar
  33. 33.
    Woop, S., Marmitt, G., Slusallek, P.: B-kd trees for hardware accelerated ray tracing of dynamic scenes. In: Proceedings of Graphics Hardware (2006), to appearGoogle Scholar
  34. 34.
    Woop, S., Schmittler, J., Slusallek, P.: RPU: A Programmable ray processing unit for realtime ray tracing. In: Proceedings of ACM SIGGRAPH, vol. 24(3), pp. 434–444. ACM Press, New York, NY, USA (2005)CrossRefGoogle Scholar
  35. 35.
    Yoon, S.E., Manocha, D.: Cache-efficient layouts of bounding volume hierarchies. Comput. Graph. Forum 25(3) (2006), to appearGoogle Scholar

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Johannes Günther
    • 1
  • Heiko Friedrich
    • 2
  • Hans-Peter Seidel
    • 1
  • Philipp Slusallek
    • 2
  1. 1.MPI InformatikSaarbrückenGermany
  2. 2.Saarland UniversitySaarbrückenGermany

Personalised recommendations