A Physically‐Based BSDF for Modeling the Appearance of Paper

Abstract

(a) (b) Paper BSDF Photograph Figure 1: A back-lit origami bird rendered with our Paper BSDF at varying paper thicknesses: (a) 0.05mm, (b) 0.26mm (our measured parameter for matte paper). On the right, a comparison between a photograph (right side) and our Paper BSDF for matte paper (left side). The scene is of an illuminated checkerboard pattern with matte paper placed in front of it. AbstractWe 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.

A Survey of BSDF Measurements and Representations

“…Papas et al [1] measured 3 different isotropic BSDFs from homogeneous translucent paper materials by using an image based measurement setup, which can be seen in Figure 7. The renderings of these isotropic materials using Papas et al's [1] BSDF model and the real photographs of these materials can be seen in Figure 1.…”

“…The renderings of these isotropic materials using Papas et al's [1] BSDF model and the real photographs of these materials can be seen in Figure 1. Papas et al used the same parameterization (0°≤ < 90°, 0°≤ < 90°, and 0°≤ < 180°) as Matusik et al [2] in their measurements.…”

“…Noisy, irregular and sparse reflectance and transmittance measurements can be represented by analytical BRDF models [7][8][9][10][11][12][13][14][15][16][17], BTDF models [1,6,18] or BSDF models [1,6,18]. However, this kind of irregular and sparse measurements cannot be represented by any datadriven material models.…”

“…Analytical BRDF models [7][8][9][10][11][12][13][14][15][16][17], BTDF models [1,6,18] and BSDF models [1,6,[18][19] try to represent measurements with a few parameters. But, analytical models fail to fit some material types (i.e., structured glasses).…”

Scatterometer and Intensity Distribution Meter With Screen Image Synthesis

“…Therefore, a fast and versatile measuring instrument is urgently required. In many fields, imaging measurement technology has been applied to improve the intensity distribution measurement and the speed of bidirectional scattering distribution function (BSDF) meters [21][22][23][24][25][26][27][28][29][30][31][32][33]. Ward presented an elegant system using a hemisphere as a projection surface and a fish-eye lens for capturing images [34,35].…”