Quake / 3D GameStudio Model .mdl
Where id’s model lineage starts, and 3D GameStudio’s too.
What an .mdl file holds
MDL is Quake’s original model format, storing vertex-animated frames against a single skin texture on a compressed integer grid. The same extension was later reused by 3D GameStudio for its own unrelated format, and both are recognised here.
Commonly seen in: Quake, 3D GameStudio, Half-Life tooling, retro engines.
| Data | Stored in MDL |
|---|---|
| Geometry | Yes |
| Materials and colour | Yes |
| Texture maps | Yes |
| Animation and rigs | Yes |
| Scene hierarchy | No |
| Read here | Yes |
| Written here | No |
Tested against a real file
The last sweep loaded minigun.MDL from Assimp test models with its 1 sidecar files through the viewer on this site: 576 triangles across 1 meshes and 1 materials, in 2.8 seconds. Every format's result is on the test results page, run 2026-09-08.
Convert MDL to another format
Every pairing has a page saying what survives the trip.
Other things to do with an .mdl file
Questions about MDL
How do I open an .mdl file?
Drop it into the viewer on this site and it opens in the browser, with the scene tree, the materials and the mesh statistics. Nothing is uploaded. If you want it in another program instead, convert it to GLB, which almost everything reads.
Is MDL a good format to archive in?
MDL carries geometry, materials, textures and animation, so an archive copy keeps nearly everything. The usual caveat applies: a format is only as future-proof as the readers that exist for it, and .mdl is well served.
Does converting MDL lose quality?
Geometry is copied vertex for vertex, so the shape does not degrade. What gets lost is whatever the target format has no field for: convert to STL and the materials go, convert to OBJ and the animation goes. The comparison table on each converter page says exactly which.
Formats that hold the same things
Or go back to the full format reference.