Extracting models from Ever17 (Xbox 360), .vmx2 format

[Xatzimi]

A little background on the game: Ever17 is a visual novel which got a re-release on the 360 with 3D models instead of sprites. It was developed by 5pb and Cyberfront. I am intending to extract those character models, and so far I have managed to extract from an .afs archive, within which is .vpk files. I extracted those further with a program called AE and got to what appears to be the model proper: a .vmx2 (and textures) which I cannot figure out how to open.
This is my first post here, but it appears no one has asked about this before. Does anyone know what a .vmx2 file is and a way I might be able to open it?
I've attached a zip of what I extracted from the VPK, and placed the original vpk file inside for reference. Thanks for the help!

Also, while I am already in the files I am curious if a proof-of-concept English text insertion is possible. I believe the script to be one of these but cannot open these in a way that leads to any coherent Japanese text: https://puu.sh/Dv7mJ/ed9bc865ad.zip

[aluigi]

I see that the vmx2 file starts with the "VMX2" magic while vpk with "DYNAPACK" but I don't see a clear table with information for extracting the content.

[Hakkou]

I was looking through the game files and I found this thread. I am not sure how to open the .vpk file in the first place, so I would appreciate help on that. Also, judging by the header of the vpk file when opened in a hex editor, there seem to be more files in the archive than the ones in the ZIP file. The same header data appears in the .vmx2 file as well, and judging by the data, it's probably a mesh with some textures and seemingly animations as well. It would be interesting if this could be investigated further, as it seems like the file would not be too difficult to split it up into even smaller files, although I'm still not sure if it could be read by any regular program.

[AlphaKretin]

Apologies if necro-posting is looked down upon here, but it seemed like a waste to make a new thread for something this obscure. I have some relevant information for anyone else who stumbles upon this thread through Google and is interested in this same topic.

Firstly, the program "AE" mentioned by the OP is naturally hard to find because of its name. I'm not sure if it would be OK to link here, but if you search for "AE - VN Tools", that should get you what you need. That program can extract the ".vpk" archives.

Secondly, "DYNAPACK", the magic in the ".vpk" files, seems to be the name of a 3D model and animation compression algorithm developed by Lawrence Ibarria and Jarek Rossignac. These files do indeed seem to be an archive of 3D models and animations - if you open a ".vmx2" file in a hex editor you can see what look like paths to animations. So I think these files may have been compressed with this algorithm. Unfortunately I can't find an implementation of it anywhere and I don't have the skill or time to create one myself, but this may be the key to unlocking this strange format. The full name of the paper is "Dynapack: Space-Time compression of the 3D animations of triangle meshes with fixed connectivity".

I'll upload a ".vpk" archive and the extracted contents, including the ".vmx2" model, with this message as another sample, since I had issues downloading what the OP provided.

[aluigi]

Ok, the files in VPK are stored sequentially:

Code: Select all

idstring "DYNAPACK"
get FILES long
for i = 0 < FILES
    get SIZE long
    getdstring NAME 255
    savepos OFFSET
    log NAME OFFSET SIZE
    goto SIZE 0 SEEK_CUR
next i

[AlphaKretin]

Thank you for this! All of the VPK archives were unpacked flawlessly. I suppose the VMX2 format is still a mystery though.

There are some interesting folder names in the file paths for the VPK archives. Most of them are in a folder called "VPK0926_FIX", except MU1, the Lemur costume model, is in a folder called "VPK0902". Presumably these are dates, September 2nd and 26th, and there was some problem that needed fixing with either the models or the Dynapack format. "izutsu_sana" is unsurprisingly the name of someone who worked on this version of the game, Sana Izutsu, but I don't think it would be productive or respectful to chase them down. Most of the reason I'm mentioning this is so that anyone else who discovers this independently can find this thread and maybe contribute in the future.

I wonder what the best hope is for trying to figure out the VMX2 format. Would it be trying to reverse engineer the game to see how it does it?