Revit Family Reference Planes IsReference Property

Creating families for use in the various Autodesk Revit software packages is an important aspect of implementing and effectively utilizing Revit within an organization.  While users that create Revit families are familiar with using Reference Planes to drive the geometry within the family, many users do not understand the purpose of the Is Reference property.  This article will look at the various options for the Is Reference property and their purpose.

The Is Reference property is pertinent to how the family will be dimensioned when it is loaded and placed in a project.  This property will dictate whether the associated Reference Plane is recogized as a dimensionable item in the project, and if so, how strong of a dimensional reference it is.  It is an often overlooked property of a family’s reference planes, but has a great impact on dimensioning to the family in a project.

To access this property:  After placing a Reference Plane, you can highlight the Reference Plane and go to the Is Reference option under the Other section of the Properties palette.  The available options are chosen from the dropdown list.

The options are as follows:

• Not a Reference
  • This option makes the reference plane seem as if it does not exist when the family is in the project.
  • When the family is placed in the project, you will NOT be able to dimension to this reference plane or snap to it in any way in the project.
  • This is a common option to use when the user should not “see” it in the project and only wants to use the reference plane within the family itself.
• Strong Reference
  • This reference plane will always be accessible to the user in the project.
  • When dimensioning, this will be a dominant plane and the mouse cursor will automatically jump to this reference plane.
  • Choose this option when this plane is a preferred dimensioning point.
  • A strong reference plane also works well when needing a plane to utilize for aligning the family with something else.
• Weak Reference
  • If a weak reference is far enough from a strong reference plane, then the mouse cursor will find this plane for dimensioning.
  • If the weak reference plane is very close to a strong reference plane, the user can use the TAB key to cycle between the strong and weak reference planes.
• Named Planes
  • The following are named planes that indicate the location of the plane in relation to the overall family model.
    • Left
    • Center (Left/Right)
    • Right
    • Front
    • Center (Front/Back)
    • Back
    • Bottom
    • Center (Elevation)
    • Top
  • There can only be one of each of these in the family.
  • These planes behave like Strong References.
  • Even if the reference plane utilizes one of these options, it can still be given any name that is desired.
  • An advantage to using these names is that when Left and Right are specified, a dimension will allow you to pick on the dimension grip and bounce between the Left, Right, and Center options.  The same applies to Front/Rear and Top/Bottom.

I hope that being aware of each of these Is Reference property options aids you in creating better families.

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