FRED Technical Support FAQs


What is the recommended computer configuration?

While we don’t recommend a specific manufacturer or model, the following items should be considered when selecting a computer to run FRED:

  • FRED only runs on Windows and we recommend Windows 7 or newer (XP is no longer supported).
  • FRED Standard will perform multi-threaded calculations on up to 4 threads while FRED Optimum supports up to 63 threads.  Any number of threads beyond the limit for your version of FRED will not be used.
  • Many components of FRED are not multi-threaded (ex. BASIC scripting calculations, model updating, etc.) and so fast CPUs are advantageous.  In many scenarios, performance will be better for a smaller number of fast CPUs compared to a larger number of slow CPUs (ex. 16 cores at 3.2 GHz vs. 24 cores at 2.4 GHz).
  • For large raytraces, RAM usage is heavy.  We recommend between 16 and 48 GB of fast RAM so that buffering operations to the hard disk is limited.
  • In some cases buffering to disk cannot be avoided (i.e. you have traced too many rays to fit into the available RAM) and it is beneficial to have a fast disk for read/write operations.  A solid state drive is recommended.
  • While FRED does not leverage GPUs for computing, the user experience and model editing is much improved with a quality graphics card.  Photon Engineering has had reliable performance from the NVIDIA NVS series graphics cards.

Do I need to upgrade to run FRED Optimum?

In general, FRED Optimum will run on the same system that FRED Regular runs on.  However, FRED Optimum can take advantage of multi-threading operations on a maximum of 63 threads while FRED Regular can only use a maximum of 4 threads.  Therefore, in order to achieve the best possible performance it may be advantageous to upgrade your computer to leverage the FRED Optimum maximum thread limit.

My graphics are behaving poorly. What can I do?

Photon Engineering has adhered strictly to the OpenGL standard, but problems may persist depending on the drivers supplied by the graphics card vendor.  The following solutions to graphics cards problems are recommended:

  1. On the Visualization tab of the FRED Preferences dialog (Menu > Tools > Preferences > Visualization), set the Pixel format to “Safe”.  This will enforce a software rendering mode.
  2. Use the GLView.exe utility included with your FRED installation to determine an acceptable OpenGL hardware rendering mode using your graphics card.  Please see FRED’s online help topic entitled “Adjust the OpenGL pixel-rendering mode” for a detailed description of how to use this utility.  In general, you want to find a pixel mode in which the “letter cube” of the GLView.exe utlity rotates without flickering (but not necessarily the fastest).  Please note that settings entered in the Preferences dialog will not take effect until the following re-start of FRED.
  3. Download and install the latest video drivers from your manufacturer’s website.

My computer crashed and I didn't save my FRED file. Anything I can do?

FRED keeps *.fru Undo files and a copy of the latest *.frs script in a user-definable Undo directory.  The Undo directory can be set in the File Locations tab of the Preferences dialog (Menu > Tools > Preferences > File Locations) by scrolling through the file list and editing the entry for “Undo directory”.  By default the Undo directory will be “C:\Documents and settings\<username>\Local Settings\Temp\Fred Undo”.  Changing the extension of the latest *.fru file to *.frd will allow the document to be recovered.

Automatic saving of the latest script for recovery purposes occurs in three instances:

  1. Execution of the command “Script > Run”
  2. Execution of the command “Script > Debug Run Start”
  3. Execution of the command “Script > Debug Step Into”

Why don't I see the expected speed improvements with my multi-core computer?

If the computer uses “Hyperthread” technology, the expected linear speed scaling does not apply.  Hyperthread technology creates virtual cpu-cores and does not offer the same functionality as having an equivalent number of physical cpu-cores.  Performance scaling can also be dependent on the specific construction of the FRED model.

Installation and Licensing

Where do I enter my license authorization? How do I update my license codes?

If the current license authorization codes have expired a license authorization dialog will be automatically opened upon starting FRED.  Otherwise, you must navigate to Menu > Help > License Authorization in order to manually open the authorization dialog.  Upon renewal of a FRED license, Photon Engineering will send new authorization codes to the registered user with instructions on entering these codes into the dialog.

Do I need to uninstall older versions of FRED in order to install a newer version?

No, you do not need to un-install older versions of FRED.  The new version will be installed into a separate directory with a path name corresponding to the version number.  However, you should be aware that FRED files are not forward compatible – after saving a FRED file in a newer version you will not be able to open the file in older versions of FRED.

Where can I get the USB key drivers?

Although the FRED installation should automatically install the necessary USB key drivers there may be instances in which the standalone key driver installation is needed.  This installer is included in the FRED installation directory at <install directory>\Utilities\Sentinel Protection Installer.exe.  Please make sure to remove all USB dongles during installation.

Can I use multiple network USB dongles on the same computer?

Yes, multiple network USB dongles can be used on the same computer.  Available licenses are the sum total of the network keys and licenses will be checked out from USB keys in the order they were plugged into the computer.  A network license monitor is available on the license server by navigating in a web browser to the address: http://localhost:6002.

I recently upgraded FRED and my network license stopped working.

Upgrading a network license to the  most recent version of FRED is a two part process that includes installation of the FRED software on the local PC as well as upgrading the Sentinel License Server on the server computer.  The Sentinel server software can be downloaded from their website at:  Also, see FRED’s Online Help topic entitled “Safenet Hardware Key – Network Setup” for more information.


How can I model a partially coherent source in FRED?

A partially coherent source can be achieved by simulating an extended source as a collection of point sources emanating from different locations (for finite conjugates) or directions (for infinite conjugates).  Each individual source will be coherent but incoherent respect to all other sources (in FRED this is achieved by using different wavelengths).  An example of implementing a partially coherent source can be found in the FRED sample files in the folder <installation dir>\Resources\Samples\Tutorials & Examples\examplePartialCoherenceDiffractometer.frd

How can I model a solar source?

The method for defining a solar source in FRED will vary depending on the required accuracy of the model.  Parameterizing the source will depend on the time of year, time of day, longitude and latitude, weather conditions, etc.  In its simplest form, the procedure below can be effective:


  1. Create a plane source with randomized ray positions and directions into an angular range (the subtense of the solar disk, about 0.5o).
  2. Add the wavelengths and weighting appropriate for a blackbody source such as the sun.  This can be accomplished by creating a blackbody spectrum. See FRED’s Online Help topic entitled “Spectrum – Blackbody” for details.
  3. Scale the wavelength weights by the atmospheric transmission values to account for weather or regional conditions.
  4. Set the power of the source in the Power tab appropriately for the solar irradiance value and the size of the system aperture.


More complex models can be achieved by using theory such as the Bird Model (   The diffuse radiance from the atmosphere can be considered isotropic and specific data can be obtained regarding the wavelength spectrum.


Why do my analysis results only show a single ray pass through my analysis surface?

For a discussion of this issue, please read FRED’s Online Help topic entitled “Analysis Planes Overview”. 

Is there any way to customize my chart view?

Custom chart views can be created by using the “Advanced” controls of the chart viewer and FRED’s Preference settings.  For a discussion on this application, please read FRED’s Online Help topic entitled “Chart Viewer – Chart Customization”.

I tried to display my analysis in the visualization view, but nothing was displayed. What's wrong?

The number of pixels that can be displayed as a texture map in the 3D view is limited by the graphics capabilities of each computer.  In the event that the texture map display fails when called from the chart viewer, only a gray surface will be displayed.  In the event that the texture map display fails when called from the Analysis Results Nodes, a warning message will be printed to the output window.  FRED uses the “Safe” pixel mode setting by default (see FRED’s Online Help Topic entitled “Preferences – Visualization” to change FRED’s default settings) and texture maps up to 1024 x 1024 pixels will typically be properly displayed.  Hardware accelerated modes should allow for proper display of texture maps with larger numbers of pixels.

Rays and Raytracing

How many rays can FRED raytrace?

FRED can raytrace and analyze up to 263 rays.

Why am I unable to write frame #a to page file #b...?

This error message indicates the likelihood that security software is interfering with with FRED’s read/write operations.  Please consult your IT department for information regarding recent updates to your security software.

Why am I unable to allocate memory for RayBuffer (RBV)?

The minimum free hard disk space is less than the amount required for the Ray Buffer pagefile.  Please read FRED’s Online Help topic entitled “Troubleshooting – Unable to allocate memory for RayBuffer (RBV)” for more information.

What should I do if I receive the error "Insufficient diskpace - unable to create another ray buffer pagefile"?

This error indicates the same problem as the “Unable to allocate memory for RayBuffer (RBV)” error, that the minimum free hard disk space is less than the amount required for the Ray Buffer pagefile.  Please read FRED’s Online Help topic entitled “Troubleshooting – Unable to allocate memory for RayBuffer (RBV)” for a solution.


How do I attach analysis planes to NURB surfaces?

The parametric construction of NURBs is fundamentally different than other native FRED surfaces, which can lead to difficulty in positioning or attaching analysis surfaces to NURBs.  Unlike the native FRED surfaces in which the origin is definite and known, imported CAD models can contain NURB surfaces of arbitrary shape, size and position.  This flexibility leads to a fundamental question, what point on the arbitrarily shaped NURB surface becomes the origin after import?  For a detailed description on attaching analysis planes to NURB surfaces, please read the NURB surface origin section of FRED’s Online Help topic entitled “File – Import CAD”.

How can I create some basic shapes in FRED?

Please see FRED’s Online Help topic entitled “Creating Basic Shapes”.

My surface doesn't look right, but I know I've entered the information correctly. What should I check?

If you are absolutely positive that the surface information is correct, the cause is most likely due to visualization settings.  Try increasing the tessellation (decreasing the tessellation scale size) for the selected entities.  For more information on the visualization attributes, please see FRED’s Online Help topic entitled “Visualization Attributes”.


I get the message "Error - Not enough storage is available to complete this operation". What should I do?

This message is encountered after having written a FRED document out to a *.frs file and attempting to run the script in v9.50 or earlier.  The solution to this error message is to remove the lines “Sub Main” and “End Sub” from the script file before running.

How do I manipulate the position/orientation of an object in script?

Manipulating the position and orientation of an object through the scripting language is accomplished by using the T_OPERATION structure and the linear transformation commands.  You can find a list of linear transformation commands in FRED’s Online Help topic entitled “FRED Commands by Usage”. For a detailed discussion and examples, please also read FRED’s Online Help topic entitled “Position / Orientation”.

Why aren't my script commands aren't being recognized by the editor?

In v9.50 and later, script commands are broken into application level and document level.  Application level script commands can be run without a FRED document open (i.e. math commands, file commands).  Document level script commands must be run with an associated FRED document or they will not be recognized by the script editor.  To identify document and application commands use the following procedure:

  1. In a script editor window, click on the “Browse Object” toolbar button.
  2. Under Library, select FREDLib.
  3. Under Data Type, select either Application or Document.