by Martha Hollowell
Instead of covering everything again in this blog post I want to answer a few of the questions and comments that came up.
Several people wanted more information about how to apply global parameters, so here are the slides from that part of the webcast. Global parameters are similar to family parameters but they are only used in the project environment, not in the Family Editor. Global parameters are not available in Revit LT.
Q: What is the main use of using shared parameters?
- Shared parameters can be used in schedules and in tags. They can also be used in other projects and exported to a database. Many companies also use them to keep parameter names consistent across all of the projects.
- Project parameters can be used in schedules, but not in tags.
Q: So then if one were to misspell a shared parameter name in one file, it would be misspelled in all files that use it?
- Yes, you need to be careful when first creating a parameter of any kind because the spelling and case of the letters is critical. If you have misspelled a shared parameter, I would recommend fixing it as soon as possible. Even if you are far along in a project before discovering it you would still be better off fixing it as shared parameters are used in multiple projects.
- Don’t forget that you need to have the fields setup in the schedule before you can create formulas from them. This includes both project and shared parameters.
Q: Can formulas use data from other schedules? i.e. Brick area - (window area + door area)
- Formulas can use any parameters that work with the category selected in the schedule. These parameters may or may not be used by other schedules.
- You don’t need to create the formula shown above because Revit automatically calculates the material area of a brick wall with the windows, doors, and other openings already extracted.
Q: Why do you have to divide some parameters by the unit to get the right number?
- When you create a formula, all of the results must have the same numerical unit type. Because there are a number of options for this I recommend that you look at the help file Troubleshooting: Formulas for Dimensions.
Q: I've made some parameters in the past that calculate values from a family. Is there a way to make them so they report the values (or calculate) from the family, and also have the user be able to override if necessary?
- Reporting parameters are instance parameters created in families. When you create a dimension and label it you can specify that it be able to report the information in the dimension to a formula or place it in a schedule. This is another situation where I recommend you look at the help file as there are multiple variables for how it is used. See About Reporting Parameters.
Parameters and Groups
Q: What is the difference between Values are aligned by Group Instance on the last dialog box below Type or Instance?
- Values are aligned per group type: (Instance Parameters only.) If an element that includes this parameter is part of multiple groups, the value remains the same for all of the groups. Changing the value in one group changes the value in all of the groups.
- Values can vary by group instance: (Instance Parameters only.) If an element that includes this parameter is part of multiple groups, the value can vary according to the group. Changing the value in one group changes the value for all other instances of that group, but does not change the value for instances of other groups that also include the element.
I hope you enjoy creating new parameters that will make your work go smoother and faster. Remember to check the full presentation out on the ASCENT YouTube channel here.