A keynote parameter is available for all model elements (including detail components) and materials. You can tag each of these elements using a keynote tag family. The keynote value is derived from a separate text file that contains a list of keynotes.
If an element already contains a value for a keynote, it displays in a tag automatically. If not, you can select the keynote value directly. Revit provides 2 sample text files for keynoting.
Keynotes assigned in a project are linked to their source keynote table. When the keynote table is changed, keynotes in the project will reflect the changes when the project is closed and reopened.
The default keynoting data provided in Revit is based on the 1995 Construction Specification Institute (CSI) Master format system, which uses 16 divisions to organize construction process and materials. This system is widely used in the United States. A more recent version of this system is based upon 50 divisions and was introduced in 2004. Revit supports both versions of the CSI system.
This system is most effective when objects that are used throughout a project are already assigned their respective keynote values. When these values are not supplied, you can assign a value as you place a keynote tag. Materials, system and component families, and detail components can have keynote parameters entered in advance.
Keynote placement tips
For example, if a door panel is not visible in plan view, you will not be able to keynote the material of the panel. The same door family can have a keynote or tag attached to the door panel's material in an elevation view, because the solid geometry is visible in the view.