MDL File Format (.mdl)
An MDL file is most often id Software's original Quake model, a small vertex-animated mesh with a single texture, or an unrelated 3D GameStudio model that happens to share the same extension, so the extension alone never says which format a given file actually is.
MDL at a glance#
| Full name | Quake / 3D GameStudio model |
|---|---|
| File extension | .mdl |
| Category | 3D Models |
| Compression | Varies from file to file |
| FileFlip support | FileFlip reads this format but does not write it |
What a .mdl file can hold#
These are the things a MDL file either supports or does not, and they are what decides whether a conversion keeps everything or quietly drops something.
| Animation | Yes |
|---|---|
| Textures and materials | Yes |
Strengths and limitations of MDL#
What MDL does well
- Quake's original MDL needs only a header, one texture and a list of frames, which is why writing a loader for it is a common exercise even now
- 3D GameStudio kept extending the same extension through later versions, up to MDL7, adding a real bone hierarchy on top of what started as pure vertex animation
Where MDL falls short
- The .mdl extension is heavily overloaded: 3D GameStudio's models and Valve's studiomdl-compiled GoldSrc and Source models are both unrelated formats that also use it
- Quake's original MDL has no skeleton, only per-frame vertex snapshots and a single low-resolution texture
- Effectively obsolete outside Quake source ports and 3D GameStudio's own legacy content
Use MDL only when working directly inside the specific pipeline that produced it, whether that's Quake modding or 3D GameStudio, since the two formats aren't interchangeable despite the shared extension.
Convert an MDL file to a modern interchange format once its origin (Quake, 3D GameStudio, or something else entirely) is confirmed, since converting the wrong format's loader against it will simply fail.
How to open a .mdl file#
A .mdl file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts MDL into a format your machine already opens, and it does it in the browser tab rather than on a server.
| Platform | Programs that open it |
|---|---|
| Windows | Noesis, MilkShape 3D, QuArK, Quakespasm |
| macOS | Quakespasm |
| Linux | Quakespasm |
| Web | FileFlip |
MDL questions people ask#
What is an MDL file?
Most commonly, an MDL file is id Software's original Quake model format from 1996, a small vertex-animated mesh with one texture, identified internally by the magic bytes IDPO. The same extension is also used by 3D GameStudio's unrelated model format and by other software entirely, so the name alone doesn't guarantee which one you have.
Is every MDL file a Quake model?
No. 3D GameStudio's model format uses the same .mdl extension across several incompatible versions, and Valve's studiomdl compiler also writes its compiled GoldSrc and Source engine models as .mdl. None of these read as a Quake model, so the file has to be checked before assuming which format it is.
What software still opens Quake's MDL format?
Modern Quake source ports like Quakespasm load the original MDL models directly, and tools such as Noesis, MilkShape 3D and QuArK read them for inspection or conversion outside the game.
Converting MDL files#
Convert MDL to another format
FileFlip does not write .mdl files, so nothing on the site converts into this format. It works as a source only.
Every conversion runs inside your browser. The file is read from your disk, the work happens on your own machine, and nothing is uploaded. How FileFlip works names the engine behind each family and how to verify that for yourself.