Unity MMD Tools (UMT)

UMT is a toolkit for maximally reproducing MikuMikuDance (MMD) behaviour in Unity. It supports drag-and-drop import of PMX models, converts VMD motion to AnimationClip assets and runs Physics for MMD rigid bodies on a native Bullet solver.

What it does

• Imports PMX models: skinned meshes, materials, bones with bind poses, and vertex-morph blend shapes, all as sub-assets of the .pmx.
• Solve the MMD transforms for transform order, append/inherit constraints, and IKs.
• Physics simulation for rigid bodies and joints. Based on Bullet 2.75 (matches MMD's version).
• Converts Character VMD motion to AnimationClip : runtime-solved (sparse curves plus IK toggles) or baked to FK with optional physics baking.
• Converts Camera VMD motion to AnimationClip.
• Builds a humanoid Avatar (optional).
• Romanizes CJK material, bone, and morph names to ASCII.
• Builds lilToon materials (optional).

Supported MMD features

PMX import

• PMX 2.0 (2.1 read compatibility; no 2.1-exclusive features)
• BDEF1, BDEF2, BDEF4 skinning
• Vertex morphs (as blend shapes)
• Group morphs (resolved to their referenced vertex morphs)
• Bones, bind poses, humanoid avatar
• IK (CCD) with iteration/angle limits and per-link axis limits
• Append/inherit rotation constraint
• Append/inherit translation constraint
• Local-axis and inverted constraint influence
• Materials: diffuse color, main texture, double-sided, edge/outline color and width
• Sphere texture (mapped to lilToon matcap)
• Transparency detection
• Textures: PNG, JPG, BMP, TGA
• Up to 4 additional UV channels (parsed)

MMD physics

• Rigid bodies: sphere, box, capsule shapes
• Rigid-body modes: kinetic (bone-attached), dynamic, dynamic + bone-aligned
• 6DOF joints (spring 6DOF / generic 6DOF)
• Ground collision
• Live physics (play mode) and physics baking (VMD)

VMD conversion

• Bone animation (runtime-solved sparse curves or baked FK)
• Morph (vertex blend-shape) animation
• IK on/off toggles (stepped curves, sparse mode)
• Camera track (two-node camera rig)

TODO

• Bone morph
• SDEF deformation (currently imported as BDEF2)
• iOS, Mac OS and Linux support

Not planned

• Legacy PMD model support
• VPD pose data
• Other morph types
• PMX 2.1 soft body and other exclusive features

Requirements

Unity 2022.3 or newer, built-in render pipeline or URP. Materials build against lilToon when it's installed, otherwise URP Unlit or built-in Unlit.

Native physics builds for Windows x64 and Android arm64-v8a. On other platforms you can still import models and convert non-physics motion, but live and baked physics need the native plugin.

Dependencies

UMT Native Plugin

UMTNativePlugin is a C++ based library wrapping Bullet 2.75 behind a small, flat Cdecl ABI that the managed P/Invoke calls into.

Unity packages

The Package Manager pulls these in automatically:

• com.unity.burst
• com.unity.collections
• com.unity.mathematics
• com.unity.nuget.newtonsoft-json

lilToon (github.com/lilxyzw/lilToon, 2.0.0+) is optional. It isn't bundled; when it's missing the importer falls back to URP Unlit / built-in Unlit.

Installation

Add the package through the Unity Package Manager (Add package from git URL, or edit Packages/manifest.json) and let it resolve the dependencies above.

Usage

Import a PMX model

Drop the .pmx and its textures into the project and the scripted importer handles it. The generated meshes, materials, bones, avatar, and any converted VMD clips become sub-assets of the .pmx — there's no separate output folder or prefab, and re-importing the .pmx re-runs the whole pipeline.

Select the .pmx for importer options: Create Avatar, Generate Debug Data, and the VMD Animations list. With debug data on, the importer also writes .metadata.json, .string-map.json, and .import.log sidecar files.

Convert a VMD motion

The cleanest path is to convert during PMX import, which keeps each motion tied to the model it was made for:

1. Add the .vmd file(s) to the project (they import as VMDAnimation assets).
2. Select the imported .pmx and open its importer inspector.
3. Add the .vmd assets to the VMD Animations list and set the frame rate and bake options (Bake IK To FK, and when baking, Bake Physics To FK with a warm-up duration).
4. Apply to reimport. Each clip is added as a sub-asset of the .pmx.

To convert against a model you didn't just import, use the standalone window at Tools ▸ UMT ▸ VMD Clip Converter: pick a Motion (needs a PMXModel) or Camera target, choose IKRuntimeSolved or IKBakedToFK (baked mode can also bake physics to FK), and write out a standalone .anim asset.

License

MIT (see LICENSE). Bundled third-party components ship under MIT / zlib / NAIST licenses; see Third Party Notices for the full attributions.