.FDF File Extension

Text file format used for data exported from .PDF form fields; typically smaller than PDF files, because they only contain form field data, not the entire form; can be created in Acrobat by selecting Advanced→Forms→Export Forms Data from the menu bar.

FDF files are commonly processed on Web servers by .CGI scripts.

An FDF file is a mathematical fitting function definition file used by Origin, a data analysis and graphing application used by various scientists and engineers. It contains all the properties about a fitting function, such as the function type, constraints, fitting parameters, a function expression, variables, and a description. FDF files may come included with Origin or be user-defined.

User-defined FDF files are created using the Fitting Function Builder in Origin. You can access the tool by selecting Tools → Fitting Function Builder.... Choose "Create a New Function" to create an FDF file or "Edit a User-defined Function" to edit an FDF file. You can also view your FDF files by selecting Tools → Fitting Function Organizer.... You can also open FDF files with a text editor since the fitting function definition is stored in plain text.

FDF files that come packaged with the program are located in the "FitFunc" subfolder of the Origin program folder. However, user-defined FDF files are typically saved in the "FitFunc" subfolder of the "User Files" folder in the Origin program folder.