Revit Family Level of Detail

The level of detail that goes into families in Revit is very important and must be thoughtfully considered when using families in projects.  The level of detail must be balanced to get the achieved results of the model, but not too much detail to bog down the model.  A family that has a great deal of 3D modeled detail can greatly affect the speed of the model and bloat the model unnecessarily.  A model that uses families with very little detail creates more work in developing sections and elevations and will not give good renderings or walkthroughs.

An excellent method of providing balance to your model is to use the family replacement procedure.  This process involves placing a basic family component for general usage in the model, and then replacing this family component with a more detailed modeled component as needed.  This may include times when a rendering or walkthrough is required.

A basic family component may use either 2D linework or basic 3D massing.  Basic 3D massing components can often be utilized throughout the project, as Symbolic Lines can be drawn on the faces of the massing so that they appear detailed in elevations and sections.  This is usually preferential to using heavily detailed families.

When creating a basic family component, it is imperative that the family contains all of the same parameter fields that will be used in a detailed family.  This allows the “information” in the BIM file to be consistent whether the model contains families with basic detail or complex detail.  If the parameters in both detail versions are consistent, it is easy to replace the families as needed for visual purposes.  Make sure that the parameters are identical in names, spelling, and case.

There are some good websites on the internet for obtaining content for your model without the necessity of creating the family component content yourself.  These sites are a good source of content, but carefully review the content before utilizing it in your model.  Some of these families are extremely modeled with very detailed 3D components and have very large file sizes.  Make sure that you really need the detailing that is contained in the model.  For example, do you really need to have the bulbs modeled in an enclosed fluorescent light fixture?

A model that is extremely detailed can cause the file to load slowly and make views regenerate very slowly.  Even if a component is not visible in a view, if the component is within the specified view clip depth, the component must be analyzed by the software for the view.  In these situations, make sure that your view clip depth is only as far as necessary.  In Revit, you can adjust this in plan view by highlighting the section (or elevation) marker and moving the arrows at the back of the clip outline.  It can also be adjusted in the View Properties in the Far Clip Offset parameter.

This same process applies to creating multi-view blocks in AutoCAD  Architecture or similar components in other software packages.


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