Part Modeling > UDFs and Groups > Placing a UDF > About Placing a UDF in a Model
About Placing a UDF in a Model
When you place a UDF, you copy the features it includes into your model. The copied features become a group that can be independent or dependent on the UDF file.
A group that is placed as independent does not update when changes are made to the UDF file. All the required UDF values are copied into the part, along with the group.
A group that is placed as dependent is changed whenever the non-variable dimensions of the UDF are altered and an update is performed.
When a UDF is created as subordinate and placed as a dependent group, it is indirectly driven by the original model of the UDF. When you retrieve the part with a dependent group, the changes from the original model are reflected in the group.
* Dependent groups update dimension values only if the features included in the UDF have not changed since the UDF was placed. If features are added to, or removed from a UDF, updating the UDF in a model does not add or remove the features. To add or remove features to or from a UDF, make a copy of the old UDF, rename it, and then recreate this new UDF in all models in which the old UDF was placed.