Modeling and rendering of realistic feathers

ABSTRACT

We present techniques for realistic modeling and rendering of feathers and birds. Our approach is motivated by the observation that a feather is a branching structure that can be described by an L-system. The parametric L-system we derived allows the user to easily create feathers of different types and shapes by changing a few parameters. The randomness in feather geometry is also incorporated into this L-system. To render a feather realistically, we have derived an efficient form of the bidirectional texture function (BTF), which describes the small but visible geometry details on the feather blade. A rendering algorithm combining the L-system and the BTF displays feathers photorealistically while capitalizing on graphics hardware for efficiency. Based on this framework of feather modeling and rendering, we developed a system that can automatically generate appropriate feathers to cover different parts of a bird's body from a few "key feathers" supplied by the user, and produce realistic renderings of the bird.

REFERENCES

• 1: Wen-Kai Dai, Zen-Chung Shih, and Ruei-Chuan Chang. Synthesizing feather textures in galliformes. Computer Graphics Forum, 14(3):407-420, August 1995.
• 2: Kristin J. Dana and Shree Nayar. 3d textured surface modeling. In Proceedings of IEEE Workshop on the Integration of Appearance and Geometric Methods in Object Recognition, pages 46-56, June 1999.
• 3: Kristin J. Dana , Bram van Ginneken , Shree K. Nayar , Jan J. Koenderink, Reflectance and texture of real-world surfaces, ACM Transactions on Graphics (TOG), v.18 n.1, p.1-34, Jan. 1999 [doi>10.1145/300776.300778]
• 4: Cristiano G. Franco , Marcelo Walter, Modeling the Structure of Feathers, Proceedings of the 14th Brazilian Symposium on Computer Graphics and Image Processing, p.381, October 15-18, 2001
• 5: James Scott Hanan , Przemyslaw Prusinkiewicz, Parametric l-systems and their application to the modelling and visualization of plants, 1992
• 6: Jan J. Koenderink and Andrea J. Van Doorn. Illuminance texture due to surface mesostructure. Journal of the Optical Society of America, 13(3):452-463, 1996.
• 7: Aristid Lindenmayer. Mathematical models for cellular interaction in development, parts i and ii. Journal of Theoretical Biology, 18:280-315, 1968.
• 8: Xinguo Liu , Yizhou Yu , Heung-Yeung Shum, Synthesizing bidirectional texture functions for real-world surfaces, Proceedings of the 28th annual conference on Computer graphics and interactive techniques, p.97-106, August 2001 [doi>10.1145/383259.383269]
• 9: Tom Malzbender , Dan Gelb , Hans Wolters, Polynomial texture maps, Proceedings of the 28th annual conference on Computer graphics and interactive techniques, p.519-528, August 2001 [doi>10.1145/383259.383320]
• 10: Yoav I. H. Parish , Pascal Müller, Procedural modeling of cities, Proceedings of the 28th annual conference on Computer graphics and interactive techniques, p.301-308, August 2001 [doi>10.1145/383259.383292]
• 11: Christopher M. Perrins and Alex L. A. Middleton. The Encyclopedia of Birds. Checkmark Books, 1985.
• 12: Emil Praun , Adam Finkelstein , Hugues Hoppe, Lapped textures, Proceedings of the 27th annual conference on Computer graphics and interactive techniques, p.465-470, July 2000 [doi>10.1145/344779.344987]
• 13: Przemyslaw Prusinkiewicz, Mark Hammel, Jim Hanan, and Radomír Mech. Visual models of plant development. Handbook of Formal Languages, 1996.
• 14: Przemyslaw Prusinkiewicz, Mark Hammel, Radomír Mech, and Jim Hanan. The artificial life of plants. SIGGRAPH 95 Course Notes, 7:1-38, 1995.
• 15: P. Prusinkiewicz , Aristid Lindenmayer, The algorithmic beauty of plants, Springer-Verlag New York, Inc., New York, NY, 1990
• 16: Balajee Ramakrishnananda and Kok Cheong Wong. Animating bird flight using aerodynamics. The Visual Computer, 15(10):494-508, 1999.
• 17: Craig W. Reynolds, Flocks, herds and schools: A distributed behavioral model, ACM SIGGRAPH Computer Graphics, v.21 n.4, p.25-34, July 1987
• 18: Bart Rulon. Painting Birds Step by Step. North Light Books, 1996.
• 19: Morgan Schramm , Jay Gondek , Gary Meyer, Light scattering simulations using complex subsurface models, Proceedings of the conference on Graphics interface '97, p.56-67, May 1997, Kelowna, British Columbia, Canada
• 20: Xin Tong , Jingdan Zhang , Ligang Liu , Xi Wang , Baining Guo , Heung-Yeung Shum, Synthesis of bidirectional texture functions on arbitrary surfaces, ACM Transactions on Graphics (TOG), v.21 n.3, July 2002
• 21: Greg Turk, Re-tiling polygonal surfaces, ACM SIGGRAPH Computer Graphics, v.26 n.2, p.55-64, July 1992

INDEX TERMS

Primary Classification:
  I. Computing Methodologies
  I.3 COMPUTER GRAPHICS
      I.3.7 Three-Dimensional Graphics and Realism
          Subjects: Color, shading, shadowing, and texture

Additional Classification:
  F. Theory of Computation
  F.4 MATHEMATICAL LOGIC AND FORMAL LANGUAGES
      F.4.2 Grammars and Other Rewriting Systems

  I. Computing Methodologies
  I.3 COMPUTER GRAPHICS
      I.3.3 Picture/Image Generation
      I.3.5 Computational Geometry and Object Modeling
          Subjects: Geometric algorithms, languages, and systems

  J. Computer Applications
  J.3 LIFE AND MEDICAL SCIENCES

General Terms:
Algorithms

Keywords:
L-system, bidirectional texture function, bird, feather, natural phenomena, rendering