CTL File

What are CTL files and how to open them

Are you having problems opening a CTL file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your CTL files.

What is a CTL file?

CTL files have multiple uses, and FaceGen Controls/distribution Densities is one of them. Read more about the other uses further down the page.

FaceGen Controls/distribution Densities

FaceGen Controls/distribution Densities files store the data that define how facial appearance varies across populations and how user-editable controls (sliders) behave in FaceGen's Statistical Appearance Models. They are generated by the FaceGen SDK's tools when building or editing the database of facial shape and texture variation. The main program that writes these files is the FaceGen SDK (specifically tools like "fg3t" or "fg3 controls") while the SDK's rendering or modeller components read them to know slider ranges, racial distributions, gender & age effects, caricature and asymmetry behavior.

Inside each file is a binary structure that is consistent for all models sharing the same geometry and texture basis ("BasisKey"). It includes version numbers for geometry and texture bases, counts of how many symmetric versus asymmetric basis modes exist, then lists of "linear controls" (directions in face‐space for sliders) for those basis subspaces. It also contains offset linear controls for age and gender, and linear offsets for race morphing (how different races morph from each other). At the end it stores density distributions per race group, including combined, geometry, and texture densities - sometimes split further by gender in newer versions.

Files begin with an ASCII signature "FRCTL001" at offset zero, followed by unsigned‐long fields for basis versions, counts for geometry symmetric/asymmetric and texture symmetric/asymmetric basis sizes, then numbers giving how many linear controls of each type. Then come the control definitions: for each control, float arrays matching the dimensionality of its basis ("GS", "GA", "TS", "TA"), a label string, then special sections for race and demographic controls, followed by the density distributions.

How to open CTL files

Important: Different programs may use files with the CTL file extension for different purposes, so unless you are sure which format your CTL file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested ten different CTL openers which you will find listed below.

Last updated: September 19, 2026

All known file formats using extension .CTL

While FaceGen Controls/distribution Densities is a popular type of CTL-file, we know of 4 different uses of the .CTL file extension. Different software may use files with the same extension for different types of data.

LabVIEW Control data

These CTL files contain the controls and indicators created in the Control Editor of LabVIEW, a virtual engineering workbench that is a system-design platform and development engine. You can change the size, color, and position of elements in your control editor. You can also import images.

Phoenix Visual Designer Third Party Control

Phoenix Visual Designer Third Party Control files store definitions of custom user interface controls used within Phoenix Visual Designer, a form design and code-generation add-on for the PowerBASIC Windows compiler. These files describe how a third party control (one not built-in) should appear and behave in a form layout and what properties it has, so that Phoenix can integrate it just like its native controls.

The creator of these control definition files is Phoenix Visual Designer. Once a third party control is defined in one of these files, Phoenix Visual Designer reads it to allow placement in the form designer, editing of its properties (such as size, style, bitmap appearance, window class), and generation of PowerBASIC source code that uses the control. The file is not a compiled binary control; rather it is a descriptive file used by the design environment and removed from source code once compiled into the final application.

Signature data near the start of the file helps Phoenix Visual Designer identify the format: for example the very first byte is 0x27, and byte 5 is 0x3D. Internal text strings that occur include ".BMP", "BEGIN VPB_", "BITMAP", "HEIGHT", "IDNUMBER", "IDSYMBOL", "INFO", "LEFT", "STYLE", "WIDTH", and "WINDOWCL". These keywords identify crucial fields that describe the appearance and metadata of the control.

Visual Basic user-defined control file

Visual Basic user-defined control files store the source of custom visual components built using classic Visual Basic (versions up to VB6). These files define a control's layout, properties, methods and events in plain text. They serve as part of an ActiveX control project: when compiled, Visual Basic bundles one or more such control definitions into a library (OCX file) that can be used in other Visual Basic projects.

Such a control definition file is produced by Visual Basic when a developer creates a UserControl object. It contains the text-form description of the control and its constituent controls (buttons, textboxes, etc.), including property settings, code for event handlers, and metadata attributes. If graphical resources (like images or icons) are used inside the control, those are stored separately in a parallel file with the same base name but a .ctx extension.

The text is human-readable and uses Visual Basic syntax: lines starting with keywords like Begin VB.UserControl, Property, Attribute VB_Name, Attribute VB_Exposed, etc. The file begins with a version declaration (e.g. VERSION "5.00") followed by sections for control layout and for its defining attributes. These attributes include VB_GlobalNameSpace, VB_Creatable, VB_PredeclaredId, VB_Exposed, VB_Name, and may include a USERCONTROL_INITIALIZE() procedure.

Various apps that use files with this extension

These apps are known to open certain types of CTL files. Remember, different programs may use CTL files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about CTL file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.