Revit families – Thinking outside the parametric box

Most of us can create a simple box that we can flex with dimensional parameters to control size. In my latest webinar – Revit Families – Thinking outside the parametric box – I looked at three aspects of family functionality that go beyond the basics covered by most introductory Revit training.

Nested families, the Family Type parameter and Line Based families. The session wasn’t intended to be a comprehensive tutorial but more of an introduction to the potential benefits these easy to understand tools could have on your efficiency when creating families, productivity when documenting projects and consistency of models and documents alike.

When you create a family in Revit, whether it’s a piece of casework, a structural base plate for a column or an air handling unit, you may find yourself recreating geometry that appears in numerous versions of these families. Anytime you see this happening you might want to consider creating these sub-components and nesting them into a more complex family.

To illustrate using the examples cited above consider the casework. You may have a type of pull or knob that you use on a variety of casework pieces. A D pull could be used on a closet door, a drawer or a kitchen cabinet door. On the base plate there may be anchor bolts that could also be used for steel or wood columns or as sill plate tie downs in wood frame construction. The AHU may use a fan coil, a fan and a motor that are also used in other mechanical equipment.

Elements can be added to a model as view specific linework, (not recommended), families containing only 2D or 3D linework, individual families or nested families.
Elements can be added to a model as
view specific linework, (not recommended),
families containing only 2D or 3D linework,
individual families or nested families.

If these sub-elements are created as separate families not only can they be used in multiple families but they can be independently tagged, keynoted and scheduled in your projects. To take it one step further you could create an entire washroom layout out of nested plumbing fixtures, casework and washroom accessories. Each sub element could be scheduled or tagged under its own object category.

If you take nested families to the next level you can select the family once it is nested into the ‘host’ family and then add a Family Type parameter. This will allow you to create a variety of options for which nested family you want the host family to use.

A Family Type parameter added to a nested family allows you to control what nested family will be used in the host family.
A Family Type parameter added to a nested family allows you to control what nested family will be used in the host family.

For example, a door could have a D pull, a knob or a lever handle as hardware options. The structural base plate could have different sizes of anchor bolts or different types. The AHU could swap out different options for the sub-elements.Revit provides two line based family templates. One to create 2D detail components and one to create model line based components. Both start out belonging to the Generic Model category and you can change them to your required family category. Line based families allow you to place elements with an instance based length by clicking a start point and an end point. Although you can create a similar family with an instance parameter for length the two click functionality is only available if you use the line based templates a as starting point.

A Line Based Generic model family allows you to place model elements along a straight path with two clicks. Similar functionality is available for detail components. - See more at: http://www.bimblog.ca/2015/04/revit-families-thinking-outside.html#sthash.LiDm66D5.dpuf
A Line Based Generic model family allows you to place model elements along a straight path with two clicks. Similar functionality is available for detail components.

So remember, if you are recreating the same ‘parts’ in multiple families consider nested families. If you want to tag, keynote and schedule those sub-elements they must be shared so Revit can find them nested in the host family. If you want multiple options for which nested family you need, look at adding a Family Type parameter. Any shared sub-component families of the same category loaded into the host family will available as an option in the project where the host family has been placed.

For ‘two click’ placement of linear or arrayed elements consider starting the family with a line based template file.

Dimitri Harvalias

About

Dimitri is a Senior Technical Consultant and Revit Guru at Summit Technologies. He draws on over 35 years of practical experience in the AEC domain. His education as a building technologist and hands-on experience in all facets of design, construction contract administration and CAD management gives him a unique perspective on the integration of BIM technology solutions to the design and project delivery process.

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