A structural member consists of a number of components whose display properties can be determined by the materials assigned to each component. When you assign materials to a structural member style, you assign one material to each physical component of the structural member. You assign materials to components in each display representation where you want the materials to be used.
If you want to use the display properties of the structural member style, instead of using material display properties, you can turn off the material assignments in the display properties of the structural member style.
Material definitions consist of display components that correspond to component types of objects. For example, the Linework component of a material is used for all linework in plan view. The Surface Hatch component of a material is used to hatch all object surfaces in three dimensional (3D) model views and in elevations.