Autodesk 256B1-05A761-1301 - AutoCAD Revit Structure Suite 2010, User Manual

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Categories, Families, and Types
Revit Architecture classifies elements by categories, families, types, and instances.
Category : A category is a group of elements that you use to model or document a building design. For
example, categories of model elements include walls and beams. Categories of annotation elements include
tags and text notes.
Family : Families are classes of elements in a category. A family groups elements with a common set of
parameters (properties), identical use, and similar graphical representation. Different elements in a family
may have different values for some or all properties, but the set of properties—their names and meaning—is
the same. For example, six-panel colonial doors could be considered one family, although the doors that
compose the family come in different sizes and materials. Structural members (such as w shapes) are another
family. See
Revit Families on page 415.
Type : Each family can have different types. A type can be a specific size of a family, such as a 30” X 42”(A0)
title block or a 32" x 84" (910 x 2110) door. A type can also be a style, such as default aligned or default
angular style for dimensions. A family can have several types. For example, a table may be available in several
sizes. Each size table is a different type within the same family.
Instance : Instances are the actual items (individual elements) that are placed in the project and have specific
locations in the building (model instances) or on a drawing sheet (annotation instances). Each instance
belongs to a family and, within that family, a particular type.
Element Properties
In Revit Architecture, most elements have two sets of properties that control their appearance and behavior:
■ Type properties are common to many elements in a family. A type property affects all instances (individual
elements) of that family in the project and any future instances that you place in the project.
■ Instance properties apply to individual instances (elements) of a family type in the project. Instance
properties tend to vary with the location of an element in a building or project. An instance property
affects only one selected element, or the element that you are about to place. For example, suppose that
you select a beam, right-click, and click Element Properties. You change one of the instance properties
and click OK. Only that beam is affected, even if the project contains other instances (individual beams)
of the same type.
For example, the dimensions of a window are type properties, while its elevation from the level is an instance
property. Similarly, cross-sectional dimensions of a beam are type properties, while beam length is an instance
property.
120 | Chapter 4 Revit Essentials