Understanding Revit Parameters – Part 2, Family and Shared Parameters

By Dennis Collin

A Revit family is so much more than a graphical symbol. It certainly fills that role, however, it can also be scheduled and be linked to tags to provide complete coordination of position and annotation within the model and across to schedules and drawings. Done correctly this information can be accessed beyond Revit and be accessed from other products like Navisworks and the BIM 360 collection of tools.

Whilst training, I sometimes get questioned about a custom family that has several bespoke parameters set, but some of the bespoke parameters are not available to schedules despite being visible within the Revit properties palette.

E.g. In the image above, we can see ‘Cadline_Notes1’ available to a schedule but ‘Cadline_Notes2’ is missing from the list. Why is that?

To understand the omission the original component family needs to be investigated and the parameters checked within the family types dialogue.

Clicking on the second notes parameter and clicking on the edit button, highlighted, shows us why the parameter is not schedulable. In the image below we can see that the non-conforming parameter has been set as a Family parameter. This type of parameter cannot be used in schedules and is intended for controlling graphics only. A shared parameter can provide control of graphics AND be scheduled, tagged and exported out to external databases.

Both Family and Shared parameters can be set as bespoke instance, or style based, type parameters, but both types can be valid in a component and some care and time needs to be spent planning on what is the purpose of the component and what is required in the long term. If you are creating many families, then consistency is essential for the naming and setting of parameters. This is much easier if parameters are set as shared since all the parameter information can be held externally within a shared parameters file.

A shared parameter file is a simple text file held ideally on a shared network resource, perhaps in a similar location to the Revit project template(s). It is created from within Revit when working on a project or creating a component. For convenience sake I tend to advise on keeping just one file or have as few as possible. Think of a shared parameter file as a library of parameter name definitions will help in consistency of naming i.e. having a parameter name as ‘Length’ rather than length or ‘L’ will make for more consistent schedules, applications of formula, conditional IF statements etc.

Within this environment parameters can be grouped, defined and set, ideally before a range of component families have been created. Whilst its possible to edit a shared parameter file via a text editor like Notepad, it is NOT recommended unless you know what you are doing, as an incorrect edit may yield syntax errors. Therefore, any shared parameter edits should go through your local Revit expert and changes are ideally made via the Revit environment.

Shared parameters are also essential for labelling bespoke fields with Revit tags. Indeed, it is the only option when creating a tag family for display bespoke data within a drawing.

Once a tag family has been set to the appropriate parameter, it will then show the parameter value in the respective project, coordinated with all other views including schedules.

Parameter types, setting up project templates, content creation and even an introduction to formulae are topics on our more advanced Revit training course and ‘At Elbow’ days. For more details on upcoming training courses please visit https://training.cadline.co.uk/ or alternatively talk to one of our team on 01784 419922.