A tool for constructing and visualising bidirectional scattering distribution functions

Abstract

The current state-of-the-art with regards to constructing and visualising bidirectional scattering distribution functions (BSDFs) for physicallybased rendering (PBR) is rather constrained, especially when wishing to employ the arbitrary light scattering models in a particular renderer. The primary interest lies with the positive hemisphere of a given BSDF representing light reflection, referred to as bidirectional reflectance distribution functions (BRDFs), with a focus on diffuse and glossy surfaces. In this final year project, the most important contribution is the implementation of a framework to construct arbitrary BRDFs. A visualisation tool is designed to complement the framework, offering an intuitive means of interfacing with it. BRDFs constructed within the framework are verified, ensuring that they are physically correct. A physically-based renderer is adapted to interact with the framework, producing an array of renders to determine whether the renders created using the framework’s implementations of BRDFs match those created using the renderer’s default implementations. Image quality metrics and a verifier built into the framework are used to evaluate the proposed tools across a variation of reflectance models. Results show physically sound implementations of the BRDFs with no difference in image quality when compared to images produced using the renderer’s standard models.