Each material definition has the following display components that determine the appearance of object components to which a material has been assigned:
After you have specified display components of an object to be By Material, then you can no longer change the display component properties of that object.
The material components correspond to groups of object display properties or to display property types. For example, the material Linework component determines the appearance of linework components in 2D plan views, such as wall shrinkwraps, mass element boundaries or door frames. Surface Hatch determines the appearance of all surface hatching on objects in model and elevation views.
When you specify that the component of an object is displayed by material, the component uses the display properties of the associated material, instead of the display properties of the object. Only object components that correspond to a physical component of the object can be assigned material definitions.
Material definitions cannot be assigned to a custom display block, but objects that are within custom display blocks may have material definitions assigned.