Opening an MDL File

The MDL file type is primarily associated with Half-Life Model Viewer.

MDLFile Extension MDL
 File extension: MDL
File type:  model file

What is an MDL file?

MDL files mostly belong to Half-Life Model Viewer. MDL files are files that store various types of model data used in different fields.
For instance, one common use is to hold 3D models for video games. The Half-Life model file used with the Half-Life Model Viewer contains data for characters and objects in a game engine. More details are available at the Valve Developer Wiki.
Other MDL files serve different roles:
  • 3D Modeling: Some MDL files store geometry, textures, and animations used in programs like Microsoft Flight Simulator X (which may use a RIFF structure) and Autodesk 3ds Max.
  • Simulation Models: Certain MDL files are created by simulation tools. For example, MATLAB’s Simulink and Vensim use MDL files to represent simulation data. You can refer to MATLAB and Vensim for more info.
  • Garment Patterns: Some MDL files are used in the fashion industry to store garment pattern designs, as seen with Lectra Modaris (Lectra).
  • Machine Learning Models: In rare cases, MDL files may contain trained machine learning models, sometimes packed using ZIP compression.
    • Despite sharing the same MDL extension, these files vary greatly in structure and content. To open or view an MDL file, it is critical to know its origin since each type requires the proper software or viewer.
    FilExt.com note: Understanding the file’s source and checking accompanying documentation can help in choosing the right application.

    How to open MDL files

    You need a suitable software like Half-Life Model Viewer to open an MDL file. Without proper software you will receive a Windows message "How do you want to open this file?" or "Windows cannot open this file" or a similar Mac/iPhone/Android alert. If you cannot open your MDL file correctly, try to right-click or long-press the file. Then click "Open with" and choose an application. You can also display a MDL file directly in the browser:. Just drag the file onto this browser window and drop it.

    Online MDL File Viewer

    Choose your .mdl file to view this image
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    How to convert an MDL file to JPG, PDF, HTML, DOC, ...

    If you want to convert or edit an MDL file, you can use our free Online MDL File Converter (powered by Convert.Guru):
    1. To do so, click the "Choose your .mdl file to view this image" button above.
    2. Your MDL file will then be displayed in the browser.
    3. Now click on "Save as..." at the top of the page.
    4. Then click the file format (e.g. PDF, JPG, DOCX, TXT, ...) you want.
    5. Your file will be converted and downloaded.

    Programs that open and convert MDL files:

    1. Half-Life Model Viewer
      See the previous paragraphs to learn more about the main application. MDL files are often referred to as Half-Life Model Viewer games because this type of file is primarily created or used by this software.
    2. 3D Design Plus Model
    3. 3D GameStudio (Model Entity) by Conitec Datasystems, Inc
      Gamestudio is an authoring suite for 2D and 3D multimedia projects; especially computer games. Generally used for actors and vehicles.
    4. Animation:Master (3D Model) by Hash
    5. ASTi Model Builder
    6. CA-Compete! Spreadsheet
    7. Digitrakker Music Module
      (by n-FaCToR)
    8. Flight Simulator (3D Model File) by Microsoft Corporation
      This file format has been used for all Microsoft Flight Simulators including Microsoft Combat Flight Simuators. The file contains 3D information of the models used. The file format is similar to the BGL format. Utility programs to produce add-ons for Microsoft Flight Simulator can convert .DXF to .MDL as does G-Max. Microsoft has a MDL conversion tool to convert the MDL header of pre-CFS2 aircraft models to the new CFS2 format. The identifying characters used for this association are - Hex: 52 49 46 46, ASCII: RIFF. This file format is classified as CAD/CAM. Related links: The MDL Converter Tool
    9. Half-life Model
      The identifying characters used for this association are - Hex: 49 44 53 54, ASCII: IDST. Related links: XnView
    10. MapShots Software
      (Crop recordkeeping software) [XML-based database files]
    11. Mighty Draw (DOS Library) by theliquidateher Software, An MCS Investments, Inc. Company
      Mighty Draw is a drawing program. It does not run on Windows versions higher than Windows 98/ME. The identifying characters used for this association are - Hex: 00 44 00 44 00, ASCII: .D.D..
    12. Moray (Wireframe Model) by SoftTronics
      (wireframe modeller supporting POV-Ray 3.1) The identifying characters used for this association are - Hex: 4D 44 4C, ASCII: MDL.
    13. Quake Model File
    14. RapidForm (Proprietary Format) by INUS Technology, Inc.
      RapidForm is an application that enables users to generate a digitally duplicated model from 3D scan data. Related links: RapidForm File Viewer
    15. Rational Rose (Object Design Model) by IBM
      Model-driven development tool.
    16. Simulink (Simulation Model) by The MathWorks, Inc.
      Simulink is a platform for multidomain simulation and Model-Based Design for dynamic systems. The identifying characters used for this association are - Hex: 4D 6F 64 65 6C 20 7B, ASCII: Model.{.
    17. Steam (Source SDK Model Content File) by Valve Corporation
      The Source engine technology, the same used to power Half-Life 2 is available to Steam subscribers. It provides enhancements in several key areas including character animation, advanced AI, real-world physics, and shader-based rendering to allow you to create game MODs. This file compiles to a .VTX file.
    18. Symbian OS MIME Type Library

    MDL file extension format:

    The file format determines how the data is stored in the file. The file format can be determined based on the file extension and the signature (the first few characters of a file). If the file extension or signature does not match the file format, errors will occur when opening or editing the file. Exact knowledge of the format is therefore important in order to solve problems occurring in files. Below you will find our evaluation of the MDL files:

    MDL is a very widely used file extension. The file type is used by a few programs, each with its own file format. However, the following two file formats are common:

    All the rest of the MDL files (45%) have different formats, the following 16 formats can be found: Simulink Model, Microsoft Flight Simulator 3D model, MoRay 3D Model, Source, ZIP, object, UTF, UMD, mdl and TransitionModel. The category is model, interior, class, base, state or case. Just click the "Choose your .mdl file to view this image" button on this page to find out what your MDL file is.

    Technical Data for MDL File Extension

    File classification:
    Game
    Identifier:
    Hex: 49 44 53 54, ASCII: IDST (provided by TrID database)
    Related files:
    max, blend, lwo, c4d, gltf, vvd, mld, vtx, phy, 2mdl, zip, m, ztmp, mcz, vtf, vmt, msh, qc, rar, plx, mdlold, slx, smd, mmdl, szp, obj, fbx, 3ds, dae, stl
    Related links:
    XnView
    Mime type:
    text/plain, application/octet-stream

    The following listing is compiled from the database produced by the 'Associate This!' program, selected data from the main FILExt database and file extension information submitted by users.

    ProgramID: AshampooMediaPlayer.AudioFile, FileType: Ashampoo Media Player+ audio file, AppName: Ashampoo Media Player+
    ProgramID: GraphicsConverterPro.mdl, FileType: Half-Life Model, AppName: GraphicsConverter-reg
    EXEFile: GraphicsConverter.exe
    ProgramID: Rose.ModelPicture, FileType: Rose Model, AppName: Visual Modeler
    ProgramID: MDLFile
    EXEFile: %ProgramFiles%\JetAudio\JetAudio.exe %1
    ProgramID: mdlfile
    EXEFile: %ProgramFiles%\MatLab7\bin\win32\matlab.exe -r open('%1')
    ProgramID: ModPlugPlayer
    EXEFile: %ProgramFiles%\ModPlug\Player\MODPLUG.EXE %1
    ProgramID: Rose.ModelPicture
    EXEFile: %ProgramFiles%\MIAF9D~1\Common\Tools\VS-Ent98\vmodeler\MSVM.EXE -dde
    ProgramID: Rose.ModelPicture
    EXEFile: %ProgramFiles%\MICROS~1\Common\Tools\VS-Ent98\vmodeler\MSVM.EXE -dde
    ProgramID: Rose.ModelPicture
    EXEFile: %ProgramFiles%\MICROS~3\Common\Tools\VS-Ent98\vmodeler\MSVM.EXE -dde
    ProgramID: Rose.ModelPicture
    EXEFile: E:\Rational\RATION~2\rose.exe -dde
    ProgramID: mdlfile
    EXEFile: C:\MATLAB7\bin\win32\matlab.exe -r open('%1')
    ProgramID: Rose.ModelPicture
    EXEFile: %ProgramFiles%\MICROS~2\Common\Tools\VS-Ent98\vmodeler\MSVM.EXE -dde
    ProgramID: XnView.Image
    EXEFile: %ProgramFiles%\XnView\xnview.exe %1
    ProgramID: mdlfile
    EXEFile: m:\MATLAB6p5\bin\win32\matlab.exe -r open('%1')
    ProgramID: Rose.ModelPicture
    EXEFile: %ProgramFiles%\Rational\Rose\rose.exe %1
    ProgramID: quick3D.mdl
    EXEFile: %ProgramFiles%\quick3D Geo\quick3D.exe %1
    ProgramID: Rose.ModelPicture
    EXEFile: J:\MICROS~1.0\Tools\VS-Ent98\vmodeler\MSVM.EXE -dde
    ProgramID: SDDocuments.Atomistic3dDocument.1
    EXEFile: %ProgramFiles%\Accelrys\MS Modeling 3.2\Studio\MatStudio.exe
    ProgramID: mdlfile
    EXEFile: F:\MATLAB6p5\bin\win32\matlab.exe -r open('%1')
    ProgramID: mdlfile
    EXEFile: %ProgramFiles%\MATLAB6p5\bin\win32\matlab.exe -r open('%1')
    ProgramID: mdlfile
    EXEFile: %ProgramFiles%\MATLAB701\bin\win32\matlab.exe -r open('%1')
    ProgramID: mdlfile
    EXEFile: %ProgramFiles%\MATLAB\bin\win32\matlab.exe -r open('%1')
    ProgramID: Rose.ModelPicture
    EXEFile: %ProgramFiles%\MICROS~4\Common\Tools\VS-Ent98\vmodeler\MSVM.EXE -dde
    ProgramID: Magos.War3ModelEditor.mdl
    EXEFile: %ProgramFiles%\WoW Extracted Models\War3ModelEditor\War3ModelEditor\War3ModelEditor.exe
    ProgramID: mdlfile
    EXEFile: %ProgramFiles%\MATLAB704\bin\win32\matlab.exe -r open('%1')
    ProgramID: mdlfile
    EXEFile: %ProgramFiles%\MATLAB\R2006a\bin\win32\matlab.exe -r open('%1')
    ProgramID: AdvancedSimModel
    EXEFile: %ProgramFiles%\Dxp.exe
    ProgramID: mdlfile
    EXEFile: %ProgramFiles%\matlabR14\bin\win32\matlab.exe -r open('%1')
    ProgramID: Rose.ModelPicture
    EXEFile: %ProgramFiles%\Microsoft Visual Studio\Common\Tools\VS-Ent98\vmodeler\MSVM.EXE -dde
    ProgramID: CognosTransformer.Model.Source.cer1
    EXEFile: %ProgramFiles%\Cognos\cer1\bin\Trnsfrmr.exe
    ProgramID: Diagramme de modÅ le Rose
    EXEFile: %ProgramFiles%\MICROS~4\Common\Tools\VS-Ent98\vmodeler\MSVM.EXE -dde
    ProgramID: mdlfile
    EXEFile: %ProgramFiles%\MATLAB\R2006b\bin\win32\matlab.exe -r open('%1')
    ProgramID: Vensim.Model
    EXEFile: %ProgramFiles%\Vensim\Venple.exe -N
    Show all 33 listingsTo Top

    an mdl model file is a special file format and should only be edited and saved with the appropriate software.

    How to solve problems with MDL files

    • Associate the MDL file extension with the correct application.
    • Update your software that should actually open model files. Because only the current version supports the latest MDL file format. Search, therefore, e.g. on the manufacturer website after an available Half-Life Model Viewer update.
    • To make sure that your MDL file is not corrupted or virus-infected, get the file again and scan it with Google's virustotal.com.
    • Click here to open your .MDL file online - secure, fast, and no downloads needed.
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