StrandStorm

Real-time Hair Rendering and Dynamics

StrandStorm is a comprehensive real-time hair rendering and simulation system that combines state-of-the-art computer graphics techniques with physically-based dynamics. Built on OpenGL 4.6 and C++17, this project implements sophisticated hair strand simulation using discrete elastic rods for realistic deformation and motion, along with advanced rendering techniques including Kajiya-Kay and Marschner shading models for photorealistic hair appearance. The system features procedural hair generation with interpolation controls, deep opacity maps for accurate hair-to-hair shadowing, and robust collision detection between hair strands and surfaces. Leveraging modern compute shaders and spatial acceleration structures like voxel grids, StrandStorm delivers interactive performance while maintaining physical accuracy, making it suitable for both research and practical applications in real-time hair visualization. The implementation draws from foundational research in computer graphics, including seminal papers on light scattering from hair fibers, discrete elastic rods, and energy-conserving hair reflectance models.

Features:

• Control hair generation and interpolation [1]
• Kajiya-Kay and Marsehner et. al. shading modes [2,3]
• Hair-to-hair shadows using deep opacity maps [4]
• Physically-based simulation of strands using discrete elastic rods [5]
• Hair-to-hair and surface-to-hair collisions with lenght constraints [6]
• Basic phong shading and shadow maps for surface illmunation.

How to build & run:

1. Clone repository.
2. cd into projects root directory.
3. mkdir a build directory.
4. Use CMake to configure and build into the build directory.
5. Run the executble generated.

References:

[1] M. Pharr, H. Nguyen, and W. Donnelly, “Chapter 23. Hair Animation and Rendering in the Nalu Demo,” in GPU gems 2: Programming techniques for high-performance graphics [2] S. R. Marschner, H. W. Jensen, M. Cammarano, S. Worley, and P. Hanrahan, “Light scattering from human hair fibers,” ACM SIGGRAPH 2003 Papers, 2003. [3] E. d'Eon, G. Francois, M. Hill, J. Letteri, and J.-M. Aubry, “An energy-conserving hair reflectance model,” Computer Graphics Forum, vol. 30, no. 4, pp. 1181–1187, 2011. [4] C. Yuksel and J. Keyser, “Deep opacity maps,” Computer Graphics Forum, vol. 27, no. 2, pp. 675–680, 2008. [5] M. Bergou, M. Wardetzky, S. Robinson, B. Audoly, and E. Grinspun, “Discrete elastic rods,” ACM SIGGRAPH 2008 papers, 2008. and general-purpose computation, Addison-Wesley, 2006. [6] M. Müller, T. Kim, and N. Chentanez, ‘Fast Simulation of Inextensible Hair and Fur’, 12 2012. [7] Millag, “Millag/discreteelasticrods: Hair simulation demo,” GitHub. [Online]. Available: https://github.com/millag/DiscreteElasticRods. [Accessed: 25-Apr-2023].