Virtual prototyping of BSDF measurements for materials with complex scattering properties

The objects with microroughness surfaces, heterogeneous media are widely used in modern optical devices, for instance in various light guiding devices, car dashboards and other illuminating systems as elements of scenes aimed to generate images with photorealistic quality. Surface or volume scattering of these objects can have very complex shape with pronounced picks, far from ideal specular or ideal diffuse ones and typically described with Bi-Directional Scattering Functions (BSDF). If model reconstructing BSDF measuring device contains inaccurateness, it can result in errors of parameters reconstruction for scattering objects and serious damage for entire optical simulation for scattering objects. In simulation model it is very preferable simulate optical parts maximally close to real measuring device. Another problem is calculation speed of model aimed for BSDF simulation. BSDF measurement devices have very high angular and spatial resolutions that results in a very ineffective from viewpoint of simulation. Moreover, BSDF functions is multidimensional, so many calculations are required to fulfill. These problems impose careful choosing of simulation model, its reasonable simplifications, selection of proper ray tracing engine. In the paper the virtual prototyping of different industrial measurement devices is considered. These devices are quite different and thus require different approaches in computer models design. The results of virtual prototyping for several samples with complex scattering properties are presented as in numerical shape of angular intensity distribution as well in qualitative as photorealistic images. All virtual prototyping simulated results are compared with measurements to prove reliability and reasonability of built models.