At the heart of the Maxwell material system is the BSDF (which stands for Bidirectional Scattering Distribution Function, - a set of algorithms that describe how light interacts with various material types).
The BSDF contains all the parameters needed to create many different types of materials, ranging from clear glass to sandblasted glass, plastics, metals and translucent materials such as skin, porcelain, and wax.
The most simple materials are created with one single BSDF, while others are a mix of several BSDFs, or even several Layers containing several BSDFs.
When a BSDF is selected in the material layer, its BSDF properties are displayed in the panel on the right hand-side. The controls are divided into 3 distinct areas: BSDF, Surface and Subsurface.
- BSDF Properties: The BSDF properties handle all settings related to the material as a whole.
- Surface Properties: The Surface properties handle all settings related to the surface of the material, such as the surface roughness and bump.
- Subsurface Properties: The Subsurface properties control the effect of translucency – or light that is scattered beneath the surface.
The following chapters go through the parameters in order, but it is important to understand that many parameters interact with each other to produce the final result.
The BSDF properties are available when the IOR parameter is set to Custom. If you set it to Measured Data you have to load an .IOR file which will provide the BSDF data from laboratory measured materials. See the IOR files page for more info about .IOR files.