Import a massing study from design software (such as SketchUp) to an in-place mass in a Vasari project when you intend to use the design in one project only. Import the design into an external mass family when you plan to use it in multiple projects. (See Importing a Design to a Mass Family Outside a Project.)
To import a design to an in-place mass
How to
For more information, see Importing or Linking CAD Files Using the Import CAD and Link CAD Tools.
The following settings are recommended:
See Import and Link Options for CAD Formats and Revit Models.
To see the mass, you may need to type ZF (Zoom to Fit) to adjust the drawing area to show the entire mass.