Interface-oriented user defined functions (UDFs) are UDFs that are meant to correspond to a custom graphical user interface (GUI). They provide an advantage in the ability to change data values whenever you need to without re-compilation. Furthermore, constructing a polished user interface to correspond to a UDF will create a consistent look and feel between Ansys Fluent and your UDF. This part of the manual will guide you through the process of creating a custom interface in Fluent that will allow you to edit and store data for later use by your UDF. Possible data types that are usable on your interface include integers, real numbers, Booleans (toggle buttons), strings, and lists. Throughout this part of the guide, you will be instructed in the process of creating an interface with each of these features, and learn how to save their values in a manner that can be accessed by your UDF.

The fundamental way in which you will create your custom interface is through the use of Fluent macros. Macros are Scheme constructs that are created by Ansys and are used in the development of the Fluent interface. Macros can have a variety of purposes in Fluent, including the use of RP Variables, the creation of Interface Elements, and the gathering of information from a mesh. As you read through this part of the guide, you will learn how to use a variety of Fluent macros as you learn to build a customized GUI.