These settings are displayed whenever a material is edited, usually by clicking on a material image in the draw task page, the volume visualisation page or the material creation dialog.
The first choice provides a list of pre-defined materials, which you can add to by setting new material properties and using the 'save' button to store them with a specific material name. By default, new materials are stored in the 'materials' sub-directory of the application data folder. These materials will be available whenever you run Stradview. The selection in this list will be blank if the current material parameters have been changed since the last material was selected.
Clicking on the material image will allow you to change the colour of the material. The other three sliders control the material roughness, how metallic it is, and the level of anisotropy. The effect of changing each of these properties can immediately be seen in the material image.
Clicking 'OK' will apply the current properties to the item which caused this dialog to be shown in the first place.