Provide the ability to create an instance parameter that contains a predefined list of selectable values in the Properties palette. Users could choose from approved options without creating a separate family type for every variation. This would reduce the number of family types needed to support common variations, improves consistency by limiting selections to approved values, while making families more flexible while remaining easy for users to modify. Would also help prevent data entry errors caused by free-text parameters.
I found it difficult to do this with nested types.
