8 file types use the .mdl file extension.

What is an MDL file?

An MDL file is a simulation model created using Simulink, a simulation and model-based design application. It contains the block diagram and block properties of a simulation.

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How to open an MDL file

Category: Data Files

Warcraft 3 3D Model Text File

An MDL file may also be a model file used by Warcraft III, a real-time strategy game developed by Blizzard Entertainment. It stores a 3D model, including objects, meshes, and textures for buildings and units. MDL files allow text-based editing of model properties before generating a binary .MDX file used by Warcraft III.

MDL files use a nested structure to create model properties. For example, a material element may include a layer property which in turn defines a transparent property for the layer.

NOTE: MDL files are the text version of MDX 3D model binary files. They can be converted to the MDX format using the MDLX Converter program. From there, you can use several modeling tools to edit the model.

Programs that open or reference MDL files

Updated: October 27, 2010

Half-Life Model File

An MDL file may also be a three-dimensional model used for characters and creatures in the Half-Life video game. It is created using polygons and texture mapping for detail. MDL models can be seen from different views (wireframe, flatshaded, smoothshaded, and textured) using the Half-Life Model Viewer.

NOTE: QC files are actually used by Valve's Source game engine, so they are not restricted to Half-Life models.

Programs that open or reference MDL files

Updated: January 22, 2015

Flight Simulator Airplane Model

An MDL file may also be a three-dimensional model of an airplane or other aircraft used by Microsoft Flight Simulator. MDL is a standard model format used by multiple versions of the Flight Simulator series.

Programs that open MDL files

Updated: October 12, 2016

Rational Rose Model File

An MDL file may also be a diagram or model created by Rational Rose software. It is used for modeling software architecture and design, and creating business models that improve predictability and productivity.

Programs that open MDL files

Updated: December 20, 2006

DigiTrakker Module

An MDL file may also be an audio tracking module file saved in the DigiTrakker Module (MDL) format, a proprietary format used by the Prodatron DigiTrakker audio application. It contains sequences, note patterns, and sound samples that represent different instruments played back based on the notes. MDL files also store metadata about the module, including the version.

Prodatron developed DigiTrakker and released it in 1995 for MS-DOS. Its MDL format is one of many module formats audio tracker developers released in the 1990s based on the .MOD Amiga Module format introduced in 1987.

The last version of Digitrakker was 3.2. Prodatron discontinued the software in January 1997, but you may still encounter MDL files created by music enthusiasts using the original application or a third-party application that supports the MDL format.

You can open an MDL file with OpenMPT in Windows by selecting File → Open... . MODPlug Player (Windows) and CocoModX (macOS) also support MDL files but are discontinued.

OpenMPT can convert MDL files to the following formats:

Programs that open MDL files

Updated: June 14, 2022

Lectra Modaris Clothing Design File

An MDL file may also be a CAD file created by Lectra Modaris, a clothing design application. It saves the "cutter's must" list (or direction card) as well as the geometry for the pieces of the garment. MDL files are used for saving new fashion design's in men's, women's, and children's clothing.

When a design is complete, it can be sent to a machine cutter that cuts the designed patterns in a roll of fabric or another material.

Programs that open MDL files

Updated: October 12, 2016

Luigi's Mansion 3D Model File

An MDL file may also be a model file used by Luigi's Mansion, a Nintendo GameCube game. It stores 3D model data for characters, including Luigi, and objects that appear in the game.

Luigi's Mansion mainly uses the MDL format for its models but also uses the .BMD model format for some models in the game.

NOTE: The mdl2obj tool can open Luigi's Mansion MDL files and convert them into .OBJ files.

Programs that open or reference MDL files

Updated: October 29, 2014