Advanced Material Rendering in Blender

Abstract

Physically correct and realistic visual appearance rendering or analysis of material surface visual properties require complex descriptive models capable of modelling material dependence on variable illumination and viewing conditions. The recent most advanced representation of visual properties of surface materials is a Bidirectional texture function (BTF). BTF is 7D function of planar coordinates, spectral coordinate, and viewing and illumination angles, respectively. Unlike smooth textures, it specifies their altering appearance due to varying illumination and viewing conditions. This BTF visual appearance dependency on viewing and illumination conditions significantly complicates not only its acquisition, representation, and modelling but also makes its rendering noticeably more demanding. BTF textures are acquired by costly measurements of real materials and their subsequent nontrivial processing. While several techniques for measurement or processing of BTF textures have been described already, there is no environment allowing BTF texture rendering. This contribution describes novel Blender texture plugin for the purpose of BTF texture mapping and rendering. The plugin benefits from our previously developed BTF Roller texture enlargement method which is the integral part of its implementation. The presented plugin allows creating realistic computer animations with additional BTF textures of any required size mapped onto an object surfaces while the other functionality of Blender retains