1.1. Starting CFX-Pre

Note: When starting CFX-Pre for the first time:

A dialog box appears that enables you to choose a GUI style (theme). When a GUI style is selected, it is stored as the GUI Style user preference for future sessions. In future sessions, if the selected GUI style is not recognized, the dialog box reappears for selection of a recognized style.
The default system font is obtained and, if it is deemed inappropriate for CFX-Pre, a dialog box appears that enables you to choose a new font. When a font is selected, it is stored as the Font user preference for future sessions.

For details on the GUI Style and Font user preferences, see Appearance.

You can start CFX-Pre in different ways:

From within Ansys Workbench choose Fluid Flow (CFX) from Toolbox > Analysis Systems or CFX from Toolbox > Component Systems. In the Project Schematic, right-click the Setup cell and select Edit.
From the Ansys CFX Launcher: set the working directory and then click CFX-Pre 2026 R1.
From the command line. The basic command is:
```
<CFXROOT>/bin/cfx5pre
```
The command line options are described in Starting CFX-Pre from the Command Line.

To start CFX-Pre from a command line, you must either:

Specify the full path to the executable (<CFXROOT>/bin/cfx5pre)
Append the path to the Ansys CFX executables (<CFXROOT>/bin/) to your PATH.
- On Windows, right-click the My Computer icon and select Properties. Click the Advanced tab, then click Environment Variables. In the System variables section, edit PATH to include the path to the Ansys CFX executables; typically this will be something like:
```
C:\Program Files\ANSYS Inc\v261\CFX\bin;
```
- On Linux, edit your .<window_manager>rc file to include the path to the Ansys CFX executables.
Once the PATH has been updated, the basic command is:
```
cfx5pre
```
Run the executable from the launcher Tools > Command Line (which has the path to the Ansys CFX executables built-in).

There are a number of optional command line flags, some of which are summarized in the following table:

Argument	Alternative Form	Usage
`-batch <filename>.pre`		Starts CFX-Pre in batch mode, running the session file you enter as an argument.
`-display <display>`	`-d`	Displays the graphical user interface on the X11 server `<display>` instead of using the X11 server defined by the DISPLAY environment variable.
`-gui`		Starts CFX-Pre in graphical user interface (GUI) mode. This is the default mode.
`-line`		Starts CFX-Pre in line interface mode.
`-def <file>`		Loads the named CFX-Solver input file after starting.
`-session <file>`	`-s`	Plays the named session file after starting.
`-cfx <file>`		Loads the named case file after starting.
`-cgns`		In order to enable importing of CGNS files into CFX-Pre, start CFX-Pre from the command line using the command line argument: `-cgns`. This command line argument is not supported, might cause problems, and is not recommended, when loading other types of files into CFX-Pre that depend on HDF5, such as CFF.
`-verbose`	`-v`	Specifying this option may result in additional output being sent to the standard output.

To view a full list of command-line flags, execute:

cfx5pre -help