Illusion formats

Looking at the games that illusion has released over the past decade, a pattern of changes can be seen.

The oldest games didn't pack any files into archives, and most of them used directx 32-bit or 64-bit format for their models. Most of the earlier des blood series and a couple games like dancing cats used this format.

Later on, binary formats started to be used, although they used the .x extension.
Biko2, Requiem hurts, and Brutish mine used files with headers OBJF, OBJI, OBJG, OBJX. Though, the files were still unpacked.

Games like des blood 4 used fpk + tbl files, which can be opened with IGFTool or khayyam.
All DB4 models used OBJN format, which can be read with khayyam.

Then when A-ga, des blood VR, biko 3, and artificial girl 2 came around, they started packing files in PP archives using tbl files for indexing (I think that's what they're for). All of the models were done in OBJM format, which can be read with khayyam or exported using JS2mesh (no bones)

Finally, battle raper 2 and oppai slider 2, and all games up to now, are packed in the familiar PP format which doesn't rely on tbl files. The xx model format began to be used, and is still in use even now. SB3Utility, PPextract, illusion wizard, and illusion morpher are the tools that are mainly used for these archives/models.

Will they continue to use this format? Or perhaps develop a newer format in the next release? Who knows.