Graphics Programs Reference
In-Depth Information
Offset vs. Elevation
Grant has created a lighting fixture modeled at 8′-0″ (2440 mm) above
the reference level in the family file. When he inserts the family into his
project, it has an Offset value of 0′-0″ (0 mm). In the lounge on the first
floor of the project, the lights need to be at an elevation of 10′-0″ (3050
mm), so he changes the Offset parameter value to 2′-0″ (610 mm) for
each instance of the fixture in the lounge.
Later that day, Grant's project manager, Lucy, is reviewing the Revit file
and selects one of the light fixtures to view its properties. She notices
the offset of 2′-0″ (610 mm) and, assuming that this is supposed to
represent the elevation of the lighting fixture, she changes the value to
10′-0″ (3050 mm). Concerned with quality control, she checks and
changes the properties of all of the fixtures in the break room area. It is
not long afterward that she receives an email from Grant wondering
why the lighting fixtures in the room are 18′-0″ (5490 mm) above the
first-floor level.
Of course, this is also a case where using multiple views such as
sections, elevations, or 3D views to examine the model would be
helpful.
If you do not want to use the Offset parameter of an instance when working
in a project file, you can control the elevation of a fixture by placing a
reference plane in the family. The plane can be dimensioned and associated
with an instance parameter to edit and manage the elevation of the fixture
easily. Draw a reference plane in an elevation view when working in the
Family Editor. Be sure to give the plane a name so that you can select it later
as the host for your fixture geometry.
You can set the reference plane as the current plane for modeling by using
the Set button on the Work Plane panel of the Create tab on the ribbon.
This lets you choose a plane, such as the one you just created, to model
yourgeometryon.Ifyouhavealreadycreatedthegeometryforyourlighting
fixture, you can select it and click the Edit Work Plane button on the Work
Plane panel of the contextual tab. In the Work Plane dialog box, click the
