Keynoting in Revit offers a company the ability to standardize their labeling of elements, materials within elements and custom detail labeling. Users can construct their own keynotes.
The Key Value is an alpha-numeric field of variable length. It determines the sorting of elements, although it does not automatically determine the branch order of the keynotes (the Parent Key Code indicates this). The Key Value is also one of the values that keynotes can be set to display. It is a short code that references the description on a keynote legend.
The description is a text field that is applicable to a specific Key Value. It has no impact on the logical tree structure.
The Parent Key Code determines under which Key Code an entry is displayed
When a Keynote file is loaded into Revit, it does some rudimentary validation and generates some warnings if errors are encountered.
Here a Key Code has a duplicate
Below is the resultant keynote structure.
C21 shows that a non-existent Parent Key Code elevates the entry to a Division of its own. Child references to it may be made through its Key Code, and Division D was allocated as such. Note that Key Codes are case-sensitive.
C13 illustrates how the Parent Key Code determines the logical structure. It should be noted that if the decimal places after the period are of differing number the alpha-numeric numbering system breaks down.
A16 shows that duplicate Key Codes are collapsed into one entry.
C19 shows that a Parent Key Code that Refers to its own Key Code is excluded from the list.
If a 3rd party app were to be coded for this process, internal logic and an interface that validates the input is critical, as is a thorough understanding of the structure of the Key Code itself.