Graphics Programs Reference
In-Depth Information
an extensive library of lookup tables is installed that can be referenced by
families.
Lookup tables
are CSV files that work like a type catalog. They provide
values for dimensions based on other dimensions within the family. The
data in lookup tables can be driven by design codes or manufacturing
standards to ensure the graphical accuracy of your components. Pipe
fittings, for example, have a nominal diameter that is used to identify the
size, but the actual outside diameter is slightly different, especially for
different pipe materials. A lookup table can provide the outside diameter
dimension for each nominal diameter that exists in the table.
Since Revit 2014, content creators have had the ability to embed lookup
tables directly into the family. In fact, the majority of families that are
installed by default already have lookup tables embedded. This greatly
reduces the issue of having to ensure that the table travels with the family
(within a project) not only when being issued to external sources but also
when your IT department is reluctant to place additional files into your
lookup table folders on a protected network drive or into folders distributed
to each computer on the network. With the lookup table embedded into the
family, you will always get a correctly sized family regardless of where that
family is loaded.
The Lookup Table Name parameter is used to identify which CSV file the
family is referencing. The location of your lookup tables is defined in your
Revit.ini
file. When you type in the name of a lookup table, you do
not need to include the full path to the file, only the name and filename
extension. As with parameter names, referencing a lookup table name is
case and context sensitive.
Once you have referenced the lookup table with the Lookup Table Name
parameter, you can access the data in the table by using a formula for the
value of a parameter. The formula using lookup table data is as follows:
text_file_lookup(Lookup Table Name, ″Column Name″,
Value if not found in table, Value found in table)
The result of this formula will apply the value found in the table to the
parameter, or it will apply the defined value given in the formula if none
is found in the table.
Figure 6.15
shows the formula used to determine the
value of the Fitting Outside Diameter (FOD) parameter of a pipe-fitting
