You can add custom blocks for components, such as door hardware, to the display components, or to replace the default display components. For example, you can replace a simple door leaf with a custom six-panel door leaf in which the custom component is to appear. You can have a different custom block for each display representation.
When you add a custom block, you can specify rules for positioning and scaling the new component. Each custom block also appears in the display properties component list so that you can control its layer, color, and linetype.
If you create a custom block from mass elements, you can use the material assignments of the mass elements to determine the display properties of the custom block.
Be sure to set the properties of objects used to create your custom blocks to ByBlock. Otherwise, you cannot control these objects through the display properties.