How about all the AIW lines, start lights, lods, checkpoints, car positions, collisions, horizons, what else... Can you do that with 3dSimEd?
I will react as if your being genuine.
Aiw, you use the rfactor aiw editor, Just like we had to do before the aiw was added to btb.
http://www.racedepartment.com/bobs-track-builder/16976-beginners-guide-making-rfactor-aiw-file.html
Startlights, you can either make them yourself in Blender or copy the ones out of an existing isi track (you can export them out of simed as 3ds and import them into Blender)
Lods, you do that in smed.
Checkpoints you add in Blender, then set the values in simed.
Car positions is done with the rfactor aiw editor ^^
Collisions, as is with all object values this is all accessible in simed.
Horizon, use Krunch skybox, you copy sky.mas from out of an existing btb export, then copy the scn instance from an existing btb exported scn file and paste it into the new one. (don't forget to include the credit)
Or you can make your own in blender.
If you don't have an existing btb exported track, then just ask someone.
what else,,, everything you can think of can be done this way, even custom shaders.
It's not easy doing it this way, there is no magic press of the button and hey presto. But you will benefit from doing it this way, you will learn other things about building tracks for the game, important things that you take for granted with BTB.
If it helps you to understand that it is possible, the Camaro I made for NAGT was built in Blender and exported to rfactor using simed.
Here is a video of it,
So,, all things are possible, it just takes a few extra steps
[ED] I knew I made this video for a reason,
If you don't want to watch the whole thing, skip forward to about 2:30, I show some brief parts of using notepad and simed to set it up for rfactor.
It's not a track i know, but the principles are all the same.