Is it possible to make available as many playable units as wanted ?

[CapZap1970]

Originally Posted by Mister_M

Ok. Interesting fact :

I've just open the NSS_Uboat9d2.dat and replaced the 3D model of the hull by the new one from Soviet Type C. With only this modification, I get instant CTD while loading a mission with the type IXD2...

Original 3D model : 9262 triangles.
New 3D model : 40424 triangles.

Is this the problem ? Is there a hardcoded limitation for the number of triangles of the hull's 3D model ?

There are mods out there for SH3 which gives extremly detailed playable submarines (Ahnenerbe, Wise), so I just don't understand...

I think the problem is more complex that just triangles....
I think the textures , the files ID's and in general all the files that belong to the new sub you are trying to use...
Also, there are lots of .cfg files involved in other folders, Basic.Cfg, Flotilla, Cfg, Library folder, Objects folder, and a looong etc.....
Those are the names of files and folders that come to my mind thinking hastily, I am sure that there are many more, and in this case, you can take Jeff-Groves's words very seriously, since he is one of the most highly qualified modders here, among many others....