I recently
replied to a question about type catalogs at RevitForum with this stream of consciousness set of comments. I thought it made sense to drop them here too since they mostly work outside of that of context too. I have altered (and added) a bit here and there to make more sense outside the context of that conversation. Here we go:
Many people like to use Excel to edit type catalogs though it is not required to do so and I usually don't bother. You can just edit the information in a text editor, Notepad ++ is a cool free one.
A Type Catalog does not technically need all the parameters that are part of the family, only the ones that vary from type to type. Values that are not in the Type Catalog will be passed on to the family from the default family type. For example you could put height, width and depth in the type catalog only if those are the only values that really change for each type. A type catalog can be quite simple to manage (without involving CSV files) when you only include the necessary values.
The new export family types feature is quite nice to make sure you have the parameters and units properly defined, especially for MEP content. It does not put parameters in a logical order, at least not one that I find satisfying. It also exports all the parameters in the family types dialog and I don't always want them all but it is easy to remove the ones I don't need.
A Type Catalog can include instance parameter values, these are the default value assigned to the parameter, the user can still change them once they are in the project, like any other instance parameter.
If 24 inches is a more useful input value than 2'-0" a type catalog will allow that even if the units in the family or project are assigned to feet and fractional inches. Just change the ##units from Feet to Inches.
Earlier I wrote that Excel is not necessary and that I don't usually use it. I do use Excel (and CSV files) to change column order because that IS a lot easier to do with it. A friend says that we can see the "matrix" when we look at the .txt file, so we don't need Excel. I save the work as a CSV file and then change the extension to .TXT. You have to delete the older txt file first. I don't bother to keep the CSV around. If I need a CSV again I just open the TXT type catalog file directly with Excel and set the delimiter options. Revit only cares about the .TXT file so no point confusing others with a pile of "irrelevant" files in the library folder.
I put the parameters (reorder them) that match the family type name in front of the list (first columns) in the catalog in the order of the naming in the type name, like 600H 800W 150D. So 600,800,150 are the very first values after the type name. I only include values that we want to set during loading and put dimensional values before informational values (text).
Related Family Interaction Advice
A family using a type catalog must be loaded properly, either with Load Family while placing a component or via Load from Library, or using a right click > reload in the Project Browser.
Do not use Edit Family (from inside a project) with families that have type catalogs, it puts all the loaded types from the project in the family. A family that has a type catalog really ought to only have one "default" type. Lately I have settled on using the name: "This family uses a Type Catalog". If I find that type in a project I know it has been loaded at least once improperly. That type will never appear in the project if the catalog is used.
Do not use Load into Project while working on the family, it does not look for or offer the type catalog.