.MDL File Extension

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.

MDL files are saved in a plain text format and typically include a list of objects. Each object contains a set of properties and values that are delimited by line breaks.

NOTE: The MDL format was replaced by the .SLX model format with the release of Simulink 2012.

You can open an MDL file in MathWorks Simulink. If you do not have MathWorks Simulink, you can open an MDL file using any text editor, including:

• Notepad++ (Windows)
• TextEdit (Mac)
• Atom

If you cannot open an MDL file in MathWorks Simulink, you can try changing the file's extension to SLX. This will usually allow you to open the file in Simulink.

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.

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.

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.

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.

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.

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:

• .MID - MIDI File
• .IT - Impulse Tracker Module
• .WAV - WAVE Audio File
• .FLAC - Free Lossless Audio Codec File
• .AU - Audacity Audio File
• .OPUS - Opus Audio File
• .OGG - Ogg Vorbis Audio File
• .RAW - Raw Audio Data
• .MP3 - MP3 Audio 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.

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.