MikuMikuDance PMX model MIME Type

What does model/x-pmx identify?

Poly uses model/x-pmx to identify MikuMikuDance PMX model files with the .pmx extension. This is a Poly-recognized media-type label, not a claim of IANA registration. The format of the bytes still determines whether a file can be opened.

A .pmx file is commonly a MikuMikuDance model. It combines geometry with character-oriented data such as bones, morphs, materials, and physics-related records. PMX model files start with PMX , including the trailing space, and declare their text encoding in the header.¹

File structure and background

PMX belongs to the MikuMikuDance model ecosystem alongside the earlier PMD format. A model and a motion file serve different purposes: PMX describes the model, while a separate motion asset can animate it.²

A signature helps identify a candidate file, but does not validate its contents. Header values and the rest of the data must agree. Changing a filename or media-type label does not convert an unrelated file into this format.

Opening and working with the file

Blender can import and export PMX through the MMD Tools add-on. The add-on also works with PMD models and VMD motion files.² Install a compatible add-on version and use its import command; ordinary Blender installation does not imply native PMX support.

Preserve the model's original texture folder and any accompanying usage terms. When moving the asset to another application, inspect material appearance and the model's pose before editing. A visually similar converted mesh can still have different rigging behavior.

Support in Poly

Poly lets you orbit, pan, and zoom around supported geometry. Find the file by name, or use visual similarity once its visual content is available. The details panel shows available mesh, material, vertex, triangle, and other scene counts.

Poly previews supported mesh content. MMD-specific physics, constraints, morph behavior, and shader effects should be checked in an MMD-aware application; a visual rendition is not a promise to reproduce the full character setup.

An optimized rendition of the 3D object or scene is provided to the agent, allowing compact yet information-rich multimodal interaction with 3D files. You can ask about the object's visible shape or compare assets, while retaining the original for authoring work.

Conversion choices

Use glTF when exchanging a supported character with a modern viewer, or OBJ when only its static geometry is needed. Keep the PMX original for further character editing, and test exported poses rather than assuming that every MMD feature transferred.