Race Track Builder and AC: sinking cars

[formidable]

I bought RAce Track Builder, and some tracks, when the car touch the road, it sinks to an infinite loop.

I checked that the material had the suffix -AC, I exported then now, and I had the same issue,

Anybody knows how can I solve, please?

Thanks!

 

[Stereo]

AC object names (when you get to the kseditor) need to start with a "1" to have collisions.

 

[formidable]

AC object names (when you get to the kseditor) need to start with a "1" to have collisions.

The grass, some objects and road starts by 1.

I think that it can be due because I edited the sat image drawing the layout, and saving now.

This is the common step in RTB with the 2 track that "eat" cars.