反射剖面精确拟合的次表面散射计算方法

Recently, with the continuous improvement of realism requirements of movies, games, virtual reality applications, etc., the realtime rendering of translucent materials such as human organs and milk has become more and more important. For most of the current subsurface scattering calculation methods, it is difficult to correct the scattering range. To tackle this estimation issue, a new subsurface scattering calculation formula is proposed to accurately represent the maximum scattering distance. First, the brute-force Monte Carlo photon tracking results are simulated to obtain the reflectance profile results. Second, the selected polynomial model is used to fit the reflectance profile to calculate the precise maximum scattering range at the shading point. To begin with, a new importance sampling scheme is proposed to reduce the number of Monte Carlo samples, thereby increasing the computational efficiency. In addition, the required parameters are only provided by the reflectance on the shading points and the mean free path of the material, so as to flexibly adjust the rendering effect. Experiments results have shown that the proposed model can avoid the previous error estimation of the scattering range, and has more accurate rendering results of the complex reflectivity area of the material. Meanwhile, the rendering rate meets real-time requirements.