Physically-accurate fur reflectance

Abstract

Figure 1: A rendering of the Wolf scene under environment lighting using (left) our physically-based double cylinder fur reflectance model with parameters from our database of animal fur samples, and (right) energy conserving Marschner model [Marschner et al. 2003; d'Eon et al. 2011] with best-fit parameters. Insets showing detailed comparisons from top to bottom using our model, Marschner model and Kajiya-Kay model. Since the Marschner model consists of only specular lobes, it often produces dark regions (limbs and tail). Furthermore, since the T T lobe is extremely strong in the Marschner model, especially for light colored fur fibers, it completely fails in heterogeneous regions (head) where dark colored fur is covered by light colored fur. The Kajiya-Kay model produces empirically plausible but hard-and-solid appearance, and it doesn't fit the measured reflectance data in Sec. 6.

A Practical and Hierarchical Yarn‐based Shading Model for Cloth

“…The further introduced D lobe enhances the realism and flexibility of the fiber shading model, enabling it to represent a wider range of cloth. The reason is that fibers are not purely glass‐like tubes with no internal scatterings as traditionally assumed and a diffuse component addresses this limitation similar to hair or fur fibers [YTJR15].…”

“…As first introduced by Marschner et al [MJC*03], fibers are glasslike cylinders and fiber scattering models generalize the light interactions with a single fiber into reflection and transmission lobes (R and TT respectively) [KSZ*15]. To approximate the multiple scatterings, the fiber‐level shading model considers an additional diffuse lobe ( D ), as suggested in [YTJR15]. The further introduced D lobe enhances the realism and flexibility of the fiber shading model, enabling it to represent a wider range of cloth.…”

“…To simplify the fiber model, we use a classic Gaussian distributions, following the literature [MJC*03; KSZ*15; YTJR15], to approximate M R , M TT and N TT , while other lobes are modeled as uniform distributions, as follows:…”

A practical ply-based appearance model of woven fabrics

“…Fiber scattering models. The reflectance profile used by our technique is related to various fiber [Aliaga et al 2017;Khungurn et al 2016;Marschner et al 2003;Zinke and Weber 2007] and fur [Yan et al 2017[Yan et al , 2015 2006; Moon et al 2008;Zinke et al 2008]. These models utilize bidirectional curve scattering distribution functions (BCSDFs) to describe how light scatters off individual fibers or fur strands.…”

3-D Simulation of Double-Bar Plush Fabrics with Jacquard Patterns

“…The methods for 3-D simulation of pile include the geometric modeling and texture generating. Csuri, [4] Neulander, [5] Sadeghi, [6] and Yan [7] drew the animal furs very clearly with the geometric method, but it was time-consuming and mostly used for offline rendering for film production and animation. Kajiya [8] plotted furs with three-dimensional texture generating method, and the plotted fur was very real and soft, but the early methods were not efficient in simulating knitting products.…”