After extracted the files from UNITARY.dat, I found the models textures in there and I believe 3d data are also in the same file but I can't figure them out.
eg: in UNITARY_002.dat offset 0x00172a10 is the first texture(MS05.tga). Right after that at offset 0x00192e50 is the second texture(MS05a.tga). And then I believe 3d data follows.
You will see a similiar pattern appears and the name MS05.tga was there as well. But I have no idea how the 3d data format are? (Can't find any float data of verts etc)
Any suggestion?

 

Thanks in advance. 
 

OYW_Samples.rar

Seems it's vif tags in the .dat files, for example 03802F69, where 0x2F (47) is the count for parts (vertices for example) of a sub mesh. There might be 232 of them:

(using shorts, not floats)

 

Edited November 29, 2025Nov 29 by shak-otay
update

sorry I am still a bit lost. What is vif tag?

Could you tell me which file sample are you used and where exactly the location(offset) did you use in you picture?

Thank you once again. 

vif tags mark the start of blocks (vertices, uvs, etc). Simply search for them in a hex editor.

(All samples seem to be chainsaws so it doesn't matter which one you choose).

Edited November 29, 2025Nov 29 by shak-otay

so in this case. I use hex editor and search for "vif"? 

You search for 0380. Best would be to use these H2O files with hex2obj:

In hex2obj_0.25b.exe load the model UNITARY_103.dat
(you can load a single H2O file then and display a sub mesh)

To care for all H2O files
choose File "SaveAs Mmesh" (multiple mesh)
to create obj files from all contained submeshes.

After hex2obj processed the H2O files there should exist the same amount of obj files 
in the ob folder named from *_0.obj to *_xx.obj.

(Since the automated tri strips algorithm doesn't really fit for PS2 everything is rather ugly, extra faces, etc.)

UNITARY_103.dat_0391.zip