Block Attributes can be used to include object data with Entity marks. When you create the Block Attribute, type the name (tag) of the attribute in the following format:
<Name_of_PSD><:>Name_of_Proprty_Definition>
For example, if the PSD is called 'LineData' and the name of the Property Definition is 'Length' the Tag would be LineData:Length. When the attribute appears in the inserted mark on a line the line's length will be shown in the mark. The values shown in the displayed attribute will update if the associated object is modified.