There are times when nesting is not avoidable or when it is appropriate. Listed below are examples of when I would consider nesting as an option.
1. TAGGING TWICE
E.g. Dishwasher and height of CW outlet
2. WHEN YOU NEED TO DO A TRICKY ARRAY
Stacking door families as an example.I found that I had to nest one level deep to keep me from going in sane inside the family editor.
3.TO DISPLAY TEXT IN A FAMILY
E.g. An opening family. Place text in a Generic annotation family and nest into host family.
4. TO DISPLAY FILLED REGION IN A FAMILY
E.g. Slab depression or to indicate columns below floor slab. Place hatch in a Detail component family & nest into host family.
5. SCALING OBJECTS THAT WONT NORMALLY SCALE IN PROJECT
You can scale tree families that don’t normally scale in a project by nesting them into another family first.
6. TURNING A HOSTED COMPONENT INTO NON-HOSTED COMPONENT
If you have a family that works well but it won’t work in linked files then nesting can be used as a work-around. I recommend re-making the family if it is used often. Update the library with a more flexible component. I generally don’t create hosted components for this reason.
7. TOO COMPLEX IN FAMILY EDITOR
In Revit there is still no permanent hide option, or a hide by type option in the Family Editor.
In the Family editor it is not possible to switch off geometry or elements that belong to another type. This can be very frustrating! In instances where families have several types that are quite different I will use nesting. E.g. When creating this door family that automatically display access clearances I did resort to one level of nesting.
8. WHEN IT’S BETTER THAN USING GROUPS
E.g. Table and chair set. Nesting will actually have less of a negative impact on your project file than if you group a set of tables and chairs and copy them 20 – 50 times in your project file. In large projects consider nesting for such situations.