Research On The Generation Method Of Physically-based Iridescent Material

In recent years,along with the rapid development of information technology,three-dimensional rendering technology has also improved and developed to more photo-realistic effects in the video games,film or other industries.3D rendering is widely used in modern technologies to provide all kinds of visual content for all walks of life,which not only benefits from the rapid update of hardware level,but also is closely related to the progress of 3D rendering technology.Physically Based Rendering(PBR)is a mainstream rendering technique that is highly regarded in both academia and industry.This technique uses physical quantities and models to describe the light transmission and light-object interaction during the rendering process,so that the rendering result is close to the visual effect of realistic object materials.Meanwhile rainbow colors have become the focus of research because of their attractive appearance.However,the current rendering results still have the problems of unnatural boundary saturation and few material types.Therefore,this paper proposes two methods to solve the problems of appearance and variety of materials based on the existing methods and techniques.The main research contents of this paper are.(1)In view of the unnatural appearance of the boundary caused by the saturation of the luminance transition out of the edge by the iridescence rendering method,this paper introduces a lightweight transformation matrix to modify the normal distribution function to achieve a more uniform highlight distribution.Firstly,assuming that there is a refractive medium outside the metal,reflection and refraction of light in the medium are calculated by using Airy summation,and then the normal of the microfacet on the microsurface is adjusted by using the three-dimensional linear transformation matrix,and the calculation of the bidirectional reflection distribution function is converted into the calculation of the cosine space,and finally the calculation is substituted into the reflection equation.Through the comparison the actual results,time of the rendering and memory consumption,the proposed method in this paper improves the rendering efficiency and quality.(2)In this paper,a new layer material is proposed to simulate the visual effect of mixing metallic material with thin-film layer.Firstly,the bidirectional reflectance distribution function flaps of the material surface are pre-processed using atomic splitting into energy,variance and mean statistics and stored in a four-dimensional lookup table,and secondly,the total internal reflection between the layered materials is calculated and stored in a three-dimensional look-up table.Then,the refraction,reflectance and energy statistics data are remapped into corresponding roughness to approximate the distribution of light on the object surface.Finally,the new distribution function is introduced into the bidirectional reflection distribution function to obtain the rendering results,thus realizing a new iridescence layered material.In this paper,through the research on the rendering method of iridescence materials,two methods are proposed to solve two problems respectively for the problems of unnatural appearance and less variety,which improve the rendering quality and ensure the physical correctness,which has certain research value and practical value.