genBSDF Tutorial

genBSDF Tutorial

complete Tutorial GenBSDF

This tutorial demonstrates how to use genBSDF to create a BSDF for a fenestration system component from a 3D model of the system. Three examples are provided, a venetian blind, an arbitrary shading system, and a prismatic daylight-redirecting device. A Bidriectional Scattering Distribution Function (BSDF) describes the way light interacts with a material including the amount and direction of reflected and transmitted light. You may have heard of BTDF (transmission) and/or BRDF (reflection), well a BSDF is essentially the combination of a BRDF and BTDF.

The LBNL format BSDF file contains angularly resolved transmission and reflection data that simulation software can use to determine how to distribute light incident on a surface. It is particularly useful for simulating daylight transmitted by a complex fenestration system (CFS). A CFS, which transmits light in non-specular directions, is differentiated from a simple glazed façade which only transmits light in the specular direction. A BSDF file can describe an entire fenestration system, including several layers of specular and scattering components or a BSDF file can describe a single component of a fenestration system. A BSDF for a scattering fenestration component can be combined with specular glazing layers and other scattering layers to create a system BSDF using LBNL WINDOW.