OME
OME is a model format used in Yakuza, Yakuza 2, and by extension, Ryu Ga Gotoku 1 + 2 HD Edition. It was phased out and replaced with GMD.
Format Overview
A typical OME file has the following order:
1) File header data
2) Object/physics data*
3) ODBP/MDBP block
MDBP is an earlier version of OME and is not supported by the game, attempting to load one may lead to a crash.
Within ODBP:
1) ODBP File header data
2) Mesh block (pointers, material ids etc.)
3) Armature block
4) File header data
5) Material group**
6) Mesh data (vertex info and face index table)
7) End block
*Unclear yet if this actually does contain physics, there seems to be coordinates for a collision shape in prop/stage object OME files.
**Doesn't seem to control anything related to actual materials, here like materials are grouped together.