CON File

What are CON files and how to open them

Are you having problems opening a CON 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 CON files.

What is a CON file?

CON files have multiple uses, and ArtCAM Post Processor Configuration is one of them. Read more about the other uses further down the page.

ArtCAM Post Processor Configuration

ArtCAM Post Processor Configuration files are plain-text scripts that instruct Autodesk ArtCAM (formerly Delcam ArtCAM) how to translate toolpaths into the specific NC (numerical control) code format required by a particular CNC machine control. They enable users to customize the syntax, layout, units, line numbering, and other formatting of the G- and M-codes that ArtCAM outputs, so that machines with different controllers, or that use different conventions, can be supported.

These configuration files are written in a simple ASCII format and use human-readable statements. The settings include a DESCRIPTION field (how the post processor appears in ArtCAM's menus), FILE_EXTENSION (what file extension the output NC file will have), UNITS (millimeters or inches), and formatting rules for motion lines, feed rates, spindle speed, etc. They can also define START-of-file and END-of-file header/footer lines, rapid and feed move formats, and numeric output styles (number of decimals, signs, field separators). Users can modify or write new configuration files by copying an existing one, editing with a plain text editor, placing it in ArtCAM's postp folder, and restarting ArtCAM or triggering it to reload the post processor.

Internally these files often start with ASCII signature text such as the word DESCRIPTION at the very beginning (offset zero), followed by defined keywords like FEED_RATE_MOVE, FILE_EXTENSION, FORMAT, START, UNITS, and LINE (or LINE_NUM_START, LINE_NUM_INCREMENT etc.).

How to open CON files

Important: Different programs may use files with the CON file extension for different purposes, so unless you are sure which format your CON 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 CON openers which you will find listed below.

Last updated: September 2, 2026

All known file formats using extension .CON

While ArtCAM Post Processor Configuration is a popular type of CON-file, we know of 3 different uses of the .CON file extension. Different software may use files with the same extension for different types of data.

Train Simulator Consist

Train Simulator Consist files are human-readable definitions used by Microsoft Train Simulator (MSTS) to specify a train consists (a locomotive plus vehicles) so the simulator knows how a train is made up and behaves in scenarios. A consist file is created when building or editing activities in MSTS using the built-in editors or external tools. The file defines what engines and wagons are in the train, what their configuration is, what limits the consist has (like speed and durability), and assigns unique identifiers to each part so MSTS or compatible software can load and display it properly. These files are stored in the TRAINS\CONSISTS folder of the MSTS installation.

The simulator reads consist files when loading services or activities involving player-controlled or AI trains. They tie together to other configuration files: the service (.srv) file will refer to a consist (.con) by name, then the consist file refers to engine and wagon definition files (.eng, .wag, etc.). Consists are also listed in MSTS editors and by community tools that read or write MSTS files. Users often edit consist files manually (in Unicode text) or via utilities like Activity Editor, Consist Builder, ConBuilder, or Open Rails tools. The file must match MSTS's syntax and must be saved in the correct folder to be recognized.

The format begins with a fixed header ("SIMISA…" etc.), followed by nested tags like Train, TrainCfg, Engine, Wagon. Keywords like Serial, MaxVelocity, NextWagonUID, Durability appear. Names are in parentheses and often quoted when containing spaces. Unique IDs (UiD) assign identifiers to each engine and wagon. If the header or keywords are not correct, MSTS reports errors or fails to load the consist properly.

Virtual Vector Configuration

We know that one CON format is Virtual Vector Configuration. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Various apps that use files with this extension

These apps are known to open certain types of CON files. Remember, different programs may use CON 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 CON file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.