Hair Modeling and Rendering
Rupali Patekar
CSE 570
March 5th 2003
Outline of the presentation
• Fundamental Issues
• Types of modeling
– Examples and Comparison
• Thesis approach to modeling
• Closing remarks
• References
Fundamental Issues
• Shape modeling
• Dynamics
– Collision detection
• Rendering
The problem of hair modeling
• Not just drawing lines.
• Specifying required hairstyles (design)
is not easy.
• Large number of primitives are stored /
rendered.
• Realism is vital.
The problem of hair rendering
• Complex interaction of light and
shadows
– Anisotropic reflection
– Self Shadowing
– Backlighting
• Aliasing
Types of modeling
• Volumetric texture based
• Particle systems
• Geometry based
– Explicit hair models
– Cluster based
Examples : Texture Mapping
•
Real Time Fur over Arbitrary Surfaces
(ACM 2001)
J. Lengyel , H. Hoppe : Microsoft Research
E. Praun, A Finkelstein : Princeton University
Examples : Volumetric Textures
• Hypertexture
– Density variation in 3D space
– 3D vector valued noise and perturbance
– Applicable over analytically
defined surfaces.
• Hypertexture
Ken Perlin, E. M. Hoffert (1989)
Examples : Volumetric Textures
• Solid Texture: Texel
– 3D texture map with surface frame and
lighting model parameters embedded over
a volume.
• Rendering: ray casting
•Rendering Fur with Three Dimensional Textures
J. T. Kajiya, T. L. Kay (1989)
Geometric Modeling
• Explicit hair model
– Force fields
– Vector field primitives
• Cluster based
– Control Hair
– Interpolation
Comparison of methods
Thesis Approach
•
•
•
•
Head approximated by a sphere
Cluster based
Control hair : B-spline
Voronoi diagram on sphere
– Surface divided into regions of control hair
influence.
• Hairs generated by interpolation
• Rendering techniques
Closing Remarks
• Open research area
• Animation is important and challenging.
• Application in the entertainment
industry
– Ice Age, Monsters Inc. , Final Fantasy etc.
References
•
State of the Art in Hair Simulation
– Nadia Magnenat-Thalmann, Sunil Hadap , Prem Kalra
– International Workshop on Human Modeling and Animation, 2000
•
Real Time Fur over Arbitrary Surfaces
– J. Lengyel, E. Praun, A. Finkelstein, H. Hoppe
– ACM Symposium on Interactive 3D Techniques, 2001
•
Hypertexture
– Ken Perlin, E. M. Hoffert
– Computer Graphics (Proceedings of SIGGRAPH ’89)
•
Rendering Fur with Three Dimensional Textures
– J. T. Kajiya, T. L. Kay
– Computer Graphics (Proceedings of SIGGRAPH ’89)
References
•
Interactive Multiresolution Hair Modeling and Editing
– T. Kim, U. Neumann
– Proceedings of ACM SIGGRAPH 2002
•
Fake Fur Rendering
– D. Goldman
– Proceedings of ACM SIGGRAPH ’97
•
A Thin Shell Volume for Modeling Human Hair
– T Kim, U Neumann
– Computer Animation 2000
•
Rendering Hair using Pixel Blending and Shadow Buffers
– A. LeBlanc, R. Turner, D Thalmann
– Journal of Visualisation and Computer Animation, 1991
Links
• Fur with Lapped Sliced Textures
– http://research.microsoft.com/research/downloads/
Questions ?