Probably the language barrier prevents us from understanding each other correctly.
Сonverting a car 3D model from ACC - is possible.
Probably some modders know something that others do not know, and this allows them to make such conversions.
For example, until recently, it was believed that the conversion of the Dirt rally - is impossible. However, at least one car and one track are already available.
The very same Graturismo - GT6 and GTsport cars are not uncommon in AC, and the first track (Tsukuba) from GTsport has recently appeared.
There are some sites on the internet, where you can learn, how to extract 3D models from some type of games. Some modder know it, but the lot of isn't.
You can find programs or scripts on that sites, which can convert the models to usable formats like: obj, fbx, dds textures etc.
(They are not the genenreal 3D model rippes like 3dripperdx or ninja, you don't need to run the game, it extracts the models from files.)
But these programs are not working 100% correct. There is a lot of bugs.
You can even rip models from Xbox or Playstatiton games!!
And there is a lot of video on youtube, how to use these programs.
You can extract all tracks and cars from Codemasters games a lot years ago. I don't know why anybody thought, that it is impossible. You can open with 3DSimed or pssg editor(textures), and there was importers for 3DSMax. You only need to open the .nefs files, but there is a special program for it. The track conversion is heavy because all the movable parts is in the center of the track, but I think the tracks converted for AC is not contains these models, or it is repositioned to their original place.
For ACC track conversion:
(I haven't got the game, I didn't tried...)
It is technically possible, because it using Unreal4 engine. There is a model viewer, which you can extract the all models and materials. I used it for GRAVEL game. We need a car for RichardBurnsRally, and we can extract from the files, open with Blender, and the convert to a common 3D format,then we can start converting into RBR. I didn't tried to open tracks from GRAVEL.
And some word for the new Dakar cars on assettorally site:
I think AC is not good in gravel. On that surface I think the best is still the RichardBurnsRally. The DirtRally 2.0 is good, but it has a lack of track (without DLCs). And than LFS, and AC is only after that...
Despite these, thanks for the cars, I will try them!!
These cars are converted from Codemasters Dirt Series, the Dakar18, and from GRAVEL game.