Bibliography

(eng): 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.