README.md

File formats

Byte layouts of the game files modkit reads and writes. The code is the reference: every format below round-trips each file the games ship byte for byte, and each page names the class that does it.

Format	Page	Read and written by	What it is
DATA.BIN	databin.md	mhp_formats.databin, mhp_formats.iso	The encrypted archive that holds every game file
PAC	pac.md	mhp_formats.pac.Pac	The container: monster models, stages, collision
PMO	pmo.md	mhp_formats.pmo, mhp_formats.p3rd.pmo, mhp_formats.psp	Models: meshes, materials, bone palette, GE display lists
TMH	tmh.md	mhp_formats.tmh.Tmh	Texture banks
Skeleton, animation	animation.md	mhp_formats.skeleton, mhp_formats.anim, mhp_formats.fu.anim, mhp_formats.p3rd.anim; mhfu_port.fk	Bone trees, bind poses, clip packs, and how the engine plays them
Stage	stage.md	mhp_formats.fu.stage.Stage; mhfu.stage; mhfu_studio.stage	st<NNN>.pac: terrain, textures, collision, and the rules for editing a map

Conventions

• Byte order is little-endian everywhere.
• Offsets are hex and count from the start of the structure the table describes. Where a format counts from somewhere else (a HITS chunk, a PMO's geometry region), the page says so.
• Types: u8/u16/u32 unsigned, s8/s16/s32 signed, f32 IEEE single, char[n] bytes. T[n] is an array of n. Sizes are in bytes.
• File ids: file_NNNNN is the name mhp-formats extract gives a file; the engine asks for it as id NNNNN + 1 (mhfu.files.ENGINE_SKEW). The functions in mhfu.files map species and stage numbers to file ids.
• RAM addresses are named by their key in packages/mhfu/src/mhfu/addresses.toml, which also holds the layouts of runtime structures.
• Games: MHFU is the EU release ULES-01213, MHP3rd is ULJM-05800. A table that does not name a game holds for both.