Importing 3D Models from Monster Hunter Frontier

Monster Hunter Frontier contains hundreds of unique monsters, weapons, armor sets, and entire game stages. To access their 3D models, I worked on a Blender add-on called MHFrontier Blender Addon, forked from a previous add-on by @AsteriskAmpersand. This fork brings compatibility with Blender 2.8 through 4.2+, stage import, and model export. It also reimplements in Python many of the core algorithms from ReFrontier’s C# codebase — notably JKR/JPK compression and decompression (Huffman + LZ77) and the recursive block packing format — making the add-on self-contained for round-trip editing without external tools.

This page walks through the full workflow: extracting game files, importing models into Blender, and rigging them with skeletons.

Prerequisites

You will need:

• Blender 2.80+ (any version up to 4.2+ works).
• ReFrontier to decrypt and decompress the game files.
• A copy of the Monster Hunter Frontier Z game files.

Installing the add-on

Download the latest ZIP from the releases page. Then in Blender, go to Edit > Preferences > Add-ons > Install... and select the ZIP file. Search for “MHFrontier” in the add-on list and enable it.

Once installed, new entries appear under File > Import and File > Export:

Locating game assets

The game files are encrypted and compressed. Before importing anything, you need to process them with ReFrontier. The relevant folders in the game directory are:

• dat/emmodel/ and dat/emmodel_hd/ for monster models (the _hd variant contains higher-resolution meshes).
• dat/motion/ for animation files.
• Stage .pac files for maps and environments.

Monster model files are named by enemy ID (e.g., em107 is Disufiroa). A full list of monster IDs is available in the ReFrontier repository. After decompression with ReFrontier, you get .fmod (model), .fskl (skeleton), and .mot (animation) files.

Importing a model

Go to File > Import > MHF FMOD and select a .fmod file. The add-on handles several things automatically:

1. Scale correction — Frontier models are 100x larger than Blender’s typical scale, so the add-on scales them down to 1/100th on import.
2. Axis remapping — Frontier uses Y-up while Blender uses Z-up. The Y and Z axes are swapped automatically.
3. Texture search — If DDS or PNG texture files are in the same directory as the model, the add-on searches for them and assigns them to the appropriate material slots (diffuse, normal map, specular).
4. Multiple meshes — A single FMOD file can contain several meshes (e.g., a weapon with multiple parts). They are all imported at once.

Importing a skeleton

Models on their own are static geometry. To pose or animate them, you need the skeleton. Go to File > Import > MHF FSKL and select the corresponding .fskl file.

This creates a hierarchy of empty objects in Blender, representing the bone tree. Each empty has a parent-child relationship matching the original skeleton structure. At this stage, the skeleton is not yet a Blender armature — it’s a tree of axis objects.

To convert it into a proper armature, select the root empty object and go to Object > Create Armature from FSKL Tree. This:

• Converts the empty hierarchy into a Blender armature with named bones.
• Automatically adds an armature modifier to the imported meshes.
• Links vertex weight groups to the correct bones.

The Disufiroa (ID 107) imported in Blender with textures and armature

Animations (experimental)

Animation import exists but is still a work in progress. With an armature selected, File > Import > MHF Motion (.mot) imports a .mot file as a Blender Action at 30 FPS (the game’s native frame rate). The add-on maps animation channels to bones and converts Frontier’s int16 rotation values to radians.

Not all animations import correctly yet — some may display incorrect bone rotations or missing channels. Contributions to improve animation support are welcome on the GitHub repository.

Importing stages

The add-on can also import entire game stages. Two modes are available:

• Container mode (File > Import > MHF Stage): Select a .pac stage container file. The add-on automatically detects and decompresses JKR-compressed segments, then imports all FMOD models found inside. Embedded OGG audio files are also extracted.
• Directory mode (File > Import > MHF Stage (Directory)): Select a folder containing multiple FMOD files to import them all at once.

Stage imports can optionally organize all objects into a Blender collection for easier scene management.

Exporting modifications

After modifying a model in Blender, you can export it back to Frontier format:

• File > Export > MHF FMOD — exports selected meshes (or all scene meshes) to the FMOD format.
• File > Export > MHF FSKL — exports an armature or empty hierarchy back to an FSKL file.

The export process reverses the coordinate transformations: scaling back to 100x and swapping the axes to Y-up. Because the add-on includes its own Python implementation of the JKR/JPK compression algorithms (ported from ReFrontier’s C#), it can produce compressed and packed files directly — no external tools needed for the model round-trip.

The FMOD format

Under the hood, FMOD files use a recursive block structure. Each block starts with a 4-byte type identifier. The main block types are:

Materials can reference up to three texture slots: diffuse/albedo, normal map, and specular/roughness. Textures are identified by image IDs and matched to DDS or PNG files on disk.

Conclusion

The Blender add-on makes Monster Hunter Frontier’s 3D assets accessible for preservation, fan art reference, and modding. Combined with ReFrontier for file extraction and FrontierTextHandler for text translation, these tools cover the full pipeline from encrypted game files to editable content and back.