Family basics

An IMPACT standard in Revit consists mainly of Revit families in a folder structure. Revit families are separate Revit specific files that are placed separately and can be imported into the project. Revit family consists of parameters for different shapes and types. 

In this section templates, family anatomy, flexing reference planes, formulas and types will be presented. As these are relevant creating/editing any family.

Selecting the right template

Figure 1. Different folders with families in IMPACT 

When starting a new family, you are prompted to select a family template: 

Figure 2. Templates for new families

In the folder ../Common/1100/1100/revit/templates/Family templates you will find ready-made family file for the following types prefilled with IMPACT parameters. Simply copy and save them to the proper folder location with a specific name. 

The files are based on the following Revit family template types:

• Beam families - Metric Structural Framing, Beams and braces template
• Column families - Metric Structural Column template
• Hollow core families – Metric structural hollow core template
• Cast-in material families - Metric Generic Face-based template
• Modifier families - Metric Generic Face-based template
• Connection families - Metric Generic Face-based template 

So if you would like to create a new modifier or connection, use Metric Generic Model face based template and save the copy to the right folder location. 

Anatomical analogy

It can be helpful to look at the creation of Revit families according to the anatomical analogy. 

• Bones = Reference Planes
• Muscles = Dimensions and parameters
• Skin = Solids, Voids & symbolic line work

Figure 3. Revit family anatomy

Start by creating the bones of your family (reference planes). This will be the scaffolding to which muscles and skin is attached. Next, the muscles that drive the family behavior and movement (dimensions with parameters) are added. Lastly, the geometry itself is laid out and connected to the reference planes. 

Flexing

When working with your family, it is important that you continuously try different values for your parameters (flexing the model). This is done to make sure that all necessary constraints have been locked and so that changes do not break any previously made constraints.

 Figure 4. Flexing symbol is a padlock 

For easier flexing “Align” tool can be used. Make sure that at the end you have main parameters flexed (locked) with mail reference planes as indicated in the picture on the left. Flexing is done when padlock is "closed". That means, while changing e.g length parameter to 200mm (original 100mm), locked border moves together with a parameter.

References 

Make sure that the object is aligned with the default center reference planes in the center. These are used for aligning the analytical model. It is very important DO NOT delete those two reference lines as they indicate the origin point for placement.

Figure 5. Origin lines that are pinned and cannot be delete

Reference lines or planes before creating a family are drawn using Revit functions under tab "Create":

 Figure 6.  Revit Create - Reference lines and planes

It is important to know the difference between thr ref. plane and ref. line: 

• Reference lines - changes only visible on one view (symbol ----)
• Reference plane - visible throughout the whole project, new elements can be drawn on this plane (top ribbon or dialogue appears) (symbol ___ )

Because a reference line has logical endpoints (as opposed to a reference plane which does not) you can lock the end points into position and you can use angle types of parameters on them. Therefore, reference planes should be used for creating parameters. 

Figure 7.  Symbols for references

Formulas

Revit parameters have more functionality by using Formulas. See separate document Revit Formula Tips & Tricks. Formulas are used for more specific functions in Family and project. Many more function you can also find online.

Figure 8. Advanced formula for void calculation

Formulas are created after all parameters are created, as formula usually includes relevant measurements. 

Types

Create types for any variants of the family needed. If many types are used, consider using a Type Catalog. A Type Catalog is created by R > Export > Family Types. This creates a text file that can be edited to add multiple new types.

The import text file must be from a family of the same category as the family you are importing into. For example, you cannot import a text file with door types into a window family. If types in the existing file have the same name as types in the import file, you are prompted to choose whether to overwrite or keep the existing types. 

Types for the family can be added by going to the family Parameters and adding new types: 

They will be visible in your product type drop list once you have selected to draw this item.

Figure 9. Different types in one family

Type is basically a size difference in family parameter. Do not create many different families, use "New types":

Figure 10.  New type and new parameter 

Tip: To switch between different objects in Revit (select one exact object), use TAB button.