MDC File Format (.mdc)
An MDC file is Return to Castle Wolfenstein's compressed variant of id Software's MD3 model format, storing most animation frames as small per-vertex byte deltas from a full base frame instead of complete positions for every frame.
MDC at a glance#
| Full name | Return to Castle Wolfenstein model |
|---|---|
| File extension | .mdc |
| Category | 3D Models |
| First released | 2001 |
| Compression | Lossy |
| FileFlip support | FileFlip reads this format but does not write it |
What a .mdc file can hold#
These are the things a MDC 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 |
| Skeletons and animation | No |
Strengths and limitations of MDC#
What MDC does well
- Delta-compressing most frames against a base frame shrinks animation data noticeably compared to storing full vertex positions for every frame the way MD3 does
- Keeps MD3's head, torso and legs split along with its tag system, so tools and pipelines built around MD3 carry over with minimal change
Where MDC falls short
- Delta compression is lossy, discarding sub-integer precision on every frame it compresses
- Effectively limited to Return to Castle Wolfenstein and the modified id Tech 3 engine it spawned, so tool support is far narrower than plain MD3's
- Inherits MD3's vertex-snapshot animation ceiling: no skeleton, so no blending or retargeting
Use MDC only when working directly inside Return to Castle Wolfenstein's modding pipeline, where the smaller animation footprint is the point.
Convert MDC to a modern interchange format when the model needs to leave that specific engine, since almost nothing outside its immediate tool ecosystem reads MDC.
How to open a .mdc file#
A .mdc file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts MDC 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 |
| macOS | iortcw |
| Linux | iortcw |
| Web | FileFlip |
MDC questions people ask#
What is an MDC file?
An MDC file is a model in the compressed variant of MD3 built for Return to Castle Wolfenstein in 2001, storing most of its animation frames as small per-vertex deltas from a base frame rather than full positions for every frame.
How is MDC different from MD3?
MDC keeps MD3's structure, including the head, torso and legs split and tag-based attachment points, but compresses most frames down to per-vertex byte offsets from a base frame instead of storing complete vertex positions in every frame. That trades a small amount of precision for meaningfully smaller animation data.
What still opens MDC files?
The open-source iortcw engine, a modernized rebuild of Return to Castle Wolfenstein's engine, loads MDC files from the original game data. General-purpose viewers like Noesis also read MDC for inspection or conversion outside the game.
Converting MDC files#
Convert MDC to another format
FileFlip does not write .mdc 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.