I'm sure there are people who have looked into this . I just did some basic testing but because of my total lack of skill with blender I don't if I achieved anything at all. Anyways btb can export directx (*.x) files and blender can open them. And blender can output kn5 files. And fbx files for the ac editor as well. But when I open the directx files in blender I get the track shape (not any objects or textures or terrain, just the road). Apparently I would need to add the textures manually? I figured that I'd probably need to edit someting about the materials anyways and blender seems just uber mega confusing. Have some of you done this and is it possible to do it (export your track from btb in directx format, then open it in blender, do some black magic in blender and then finish it off with the official editor)?