I replied via PM to a nice guy from the forums some days ago, regarding track creation. So I'll copy&paste my reply and add a couple of new things I know about it.
So for the track, I'm not very well informed on the graphics part of the program I'll tell you guys just some basic information and I'll have to ask you to wait for the official documentation.
As with cars, you can create your track in any 3D editor you like, as long as it exports in .FBX format. Then you import that FBX file in our 3D editor and you can assign shaders in there, looking at your track as it will appear in the game, because the editor uses the same gfx engine with the game.
So first of all, in AC we have 2 meshes. One is for the graphics part and it is everything you visualise. There is no real limit on the number of polygons you can create, but obviously it depends on the RAM of the PC. So generally, our track artist, uses around 2 million polygons, but you will need LODs if you use such a high number, to be sure that the track will have decent frame rates also on lower PC configurations.
The other mesh is the one where the cars physically drive. It is invisible and it is needed that way because it is the correct way to reproduce the tarmac of Laser Scan tracks. For laser scan tracks in average we use about 1 million polygons for this invisible mesh, but obviously if you don't have a laser scan track, you don't need to make it that dense.
You can use either dds or png textures, better dds I'm told. Limit of textures is in the Video RAM. I've been told that multitexturing is a bit difficult to explain here so wait for the official documentation, but it is not similar to rf2...don't know what this means.
From what I understand, in rF you need to have a high density because every vertex can have a different specification and infinite texture levels both graphically and physically. That means that every vertex can have specific texture, shader, grip, bumpiness, FF effect ecc ecc. Please forgive me if I'm too generic or made big mistakes in this, not an expert about it.
In AC you can mix textures with a mask and we can have max 4 levels in the shader for asphalt and grass. Then we control everything from the texture without need to have big density of vertices. Again, just referring what I've been told, with our system you need some more knowledge in photoshop, handling the masks, but on the other hand in just one polygon and 4 vertices you could design a whole simple circuit with asphalt, grass and sand so to give an extreme example.
Technically if you learn a bit how to make tracks for nKP then it's not difficult to take that knowledge and apply it for AC tracks. So probably you could study a bit how textures work in netKar Pro, although I'm aware that both the documentation and the editor for nKP track creation are not very good. This will change in AC for sure.
That's all I know for know, sorry if I can't help you with more details, but if I learn more, I'll share it with you, again sorry for any inaccuracies and errors, not my cup of tea.
