Warning: Parameter Doesn't Exist in the Family. It Will Be Ignored.

Many Revit users and manufacturers creating content are taking advantage of the ability to include a Type Catalog with their loadable families.  In short, a Type Catalog is a text file that contains parameters and specifies values for mutiple family types.  This is most useful when a family contains several types, such as a light fixture.  Instead of having to create each individual type within the family and fill out the parameters, the Type Catalog supplies the values from the text file.  The other advantage is that it allows a user to only load the types that they want in the project.  You'll know that the family you are loading is using a Type Catalog when you see a dialog that looks like this:

 
  
(For more information on creating Type Catalogs, you can download the Revit MEP Families Guide here.) 

The purpose of this post is to address an issue that sometimes occurs when a user attempts to load a family with a Type Catalog.  The following warning may appear after selecting one or more types:

  

You'll notice that the warning specifies the name of the parameter that is being "ignored":  Description.  If you expand the warning dialog, any other parameters that have this same problem will also be listed.  In this example, there are two parameters that are covered by the warning, Description and URL.

 
  

If you close the warning, the family still loads, but what does this warning mean?  First off, this error is somewhat misleading.  If you open the family and open the Types dailog, you'll see that the parameters do indeed exist.  So what is this warning really saying?

Recall that the Type Catalog is supplying values for parameters in the family based on the associated text file.  So when you select one or more types from the Type Catalog when loading the family, the text file is read and Revit attempts to place the values in the respective parameters.  However, Revit "expects" that there is a default value specified for each parameter that is in the Type Catalog.  If a default value was not included for these parameters when the family was created, Revit ignores the parameters and does not place any values for them.  This is what you'll see when you open the family and look at the parameters:

 

The fix?  Simply edit the family and supply a default value for any parameter listed in the warning dialog, save the family and reload it into the project.  Now the warning will not appear and the values will be placed in their respective parameters based on the Type Catalog text file.

Comments

[Erik]

In an effort to control (or at least recognize cases of) users modifying contents, we have toyed with the idea of a nonsensical default value. Then if a user creates a new type (since it is not in the type catalog) it will use that value and either not be able to make the type or at least give the user pause to think whether or not they should be doing that.

With over a hundred users of all different skill levels it can be hard to trouble shoot if they all modify content "willy-nilly."

You can see a blog post that shows something similar at http://whosafraidofthebigbadbim.blogspot.com/search?q=type+catalog

[Jeremy]

Erik, thank you for the feedback and providing the link to the related blog article. Great concept regarding the use of default values that would jump out to a user. I'm sure our readers will find this information very valuable. Thanks for visiting the Revit Clinic.

[Jeff S.]

Erik,

I am having trouble envisioning a nonsensical default value. Would this be like 'John Doe' as a text value for manufacturer, instead of 'Generic Manufacturer'. I personally just put a "-" in as the default value, and let my type catalog (TC) do the rest. If a user needs a type not available from the TC, then I have them duplicate an existing type, rename & modify those parameters. I have 7-9 door families, each with 180+ different types (sizes, door panel, frame information, etc.), so chances are they don't need to do much in the way of type creation.

Good article, and I'll be referring people to this, when they start building families with TC's.

[Top Grade Acai]

very informational... educative as well, i read and felt like reading over and over again....good job!