Importance Sampling for Cloth Rendering Under Environment Light

We propose an importance sampling method for rendering cloth which consists of interwoven threads under environment light. As the scattering model for cloth, our method employs a microcylinder model proposed by Sadeghi et al. [1]. Our method represents the environment light with a linear combination of spherical Gaussians, and the reflectance of interwoven threads in the microcylinder model is represented by Gaussian functions. Since the product of environment lighting and the reflectance of interwoven threads can be represented by a linear combination of Gaussians, our method can perform an importance sampling by setting a probability density function proportional to the product of Gaussians. Our importance sampling method can render realistic images of cloth with less noise compared to the uniform sampling with the same number of sampling.