A Physically-Based BSDF for Modeling the Appearance of Paper

• Published in: Computer graphics forum Vol. 33; no. 4; pp. 133 - 142
• Main Authors: Papas, Marios, de Mesa, Krystle, Jensen, Henrik Wann
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.07.2014
• Subjects: Analysis; and texture; Categories and Subject Descriptors (according to ACM CCS); Computer based modeling; Computer graphics; Diffusion layers; I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism-Color; I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism—Color, shading, shadowing, and texture; Mathematical models; Multimedia computer applications; Reflection; Rendering; Roughness; Scattering; shading; shadowing; Studies; Surface chemistry
• ISSN: 0167-7055; 1467-8659
• DOI: 10.1111/cgf.12420

We present a novel appearance model for paper. Based on our appearance measurements for matte and glossy paper, we find that paper exhibits a combination of subsurface scattering, specular reflection, retroreflection, and surface sheen. Classic microfacet and simple diffuse reflection models cannot simulate the double‐sided appearance of a thin layer. Our novel BSDF model matches our measurements for paper and accounts for both reflection and transmission properties. At the core of the BSDF model is a method for converting a multi‐layer subsurface scattering model (BSSRDF) into a BSDF, which allows us to retain physically‐based absorption and scattering parameters obtained from the measurements. We also introduce a method for computing the amount of light available for subsurface scattering due to transmission through a rough dielectric surface. Our final model accounts for multiple scattering, single scattering, and surface reflection and is capable of rendering paper with varying levels of roughness and glossiness on both sides.