Thank you for the interest and idea. For displacement support I would need to research some image file format that conversion to displacement would be possible. That would be a very challenge, which could well be the next level for conversion. I definitely am interested to try that.

I think that I might hit the goal on texture coordinates with splitted geometry, at least the resulting obj files looked very promising. I try first to get some base code done and then add selectable options. Now I have to test, how the (splitted) geometry texturing have been succesful.