Accurately modeling how light interacts with cloth is challenging, due to the volumetric nature of cloth and the multiscale nature of cloth appearance, where microstructures play a major role in the overall appearance at higher scales. Recently, significant effort has been put in developing better microscopic models for cloth structure, which have allowed rendering fabrics with unprecedented fidelity. However, these highly-detailed representations have made severe simplifications on the scattering by individual fibers forming the cloth, ignoring the impact of fiber's shape, and avoiding establishing connections between the fibers' appearance, and its optical and fabrication parameters. In this work we put our focus in the scattering of individual cloth fibers; We introduce a physically-based scattering model for fibers based on low-level optical and geometric properties of the fibers, relying on the extensive textile literature for accurate data. We show that scattering from cloth fibers exhibit much more complexity than current fiber models, showing important differences between cloth type, even in averaged conditions due to longer cloth views. Our model can be plugged in any framework of cloth rendering, matches scattering measurements from real yarns, and it is based on actual parameters used in textile industry, allowing predictive bottom-up definition of cloth appearance.

@Article\{ACGOLJ17,
  author       = "Aliaga, Carlos and Castillo, Carlos and Gutiérrez, Diego and Otaduy, Miguel A. and Lopez-Moreno, Jorge and Jarabo, Adrián",
  title        = "An Appearance Model for Textile Fibers",
  journal      = "Computer Graphics Forum (Proc. of the Eurographics Symposium on Rendering)",
  number       = "4",
  volume       = "36",
  year         = "2017",
  url          = "http://gmrv.es/Publications/2017/ACGOLJ17"
}