CGL File

What are CGL files and how to open them

Are you having problems opening a CGL 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 CGL files.

What is a CGL file?

CGL files have multiple uses, and Cabri 3D Language is one of them. Read more about the other uses further down the page.

Cabri 3D Language

Cabri 3D Language files define all of the textual user‐interface messages used by Cabri Geometry II (also known as Cabri II Plus), including menu labels, dialog box prompts, tool‐names, error messages and other visible text. Such a language module allows the software's menus, messages and labels to be translated into different human languages without changing the program logic.

These files are created by Cabri-Geometry II / Cabri II Plus and are loaded at runtime when a user selects a language via the Options ▸ Language menu. Once a language file is installed, the program immediately displays all interface text in that language. After installation, the software may ask whether this language file should be used routinely on startup. It is also possible to drag a language file into the program to install it.

Files begin with a specific ASCII header identifying them as this language format, namely the string LanguageCabriIIvers. at the very start of the file.

How to open CGL files

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

While we have not verified the app ourselves yet, our users have suggested a single CGL opener which you will find listed below.

Last updated: August 31, 2026

All known file formats using extension .CGL

While Cabri 3D Language is a popular type of CGL-file, we know of 2 different uses of the .CGL file extension. Different software may use files with the same extension for different types of data.

Creative Graphics Library Driver

Creative Graphics Library Driver files are binary driver modules produced by Creative Technology Ltd in the mid-1990s for use with their 3D Blaster line of graphics cards. They implement the company's proprietary CGL (Creative Graphics Library) API, which games and demos call upon to render 3D graphics using these drivers. These files supply hardware-specific routines such as texture loading, buffer swapping, rendering control, and other low-level graphics operations.

These driver files are not standalone 3D models or scene descriptions. An application that supports the CGL API loads them to translate generic graphics calls into hardware commands specific to a particular GPU. They are produced during the driver development process by Creative's SDK tools and are consumed by compatible DOS or early Windows games or demos that include a CGL driver load step.

Each file begins with an ASCII header starting "HotLink CGL Rev 2", followed by notices such as "Copyright (C) 1995-1996 Creative Technology Ltd. All rights reserved." Internal symbols inside the file include names like CGLSELECTRENDERBUFFER, CGLCOPYDISPLAYBUFFER, CGLSETLOGICALOPSMODE, CGLSETSTIPPLEPATTERN, and others reflecting the available API functions. At offset 0x77 the file holds a driver type byte that encodes whether the driver uses fixed-point or floating-point math and whether it uses a register-based or stack-based calling convention.

Various apps that use files with this extension

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

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