I tried this quite a while back in UDK, but it turned out impossible because of a native engine stall whenever the vehicle was upside down. UE4 does not seem to have this limitation anymore so I successfully implemented driving on the ceiling, albeit in a quite hacked manner.
Disabling gravity makes the tires lose all grip ( https://answers.unrealengine.com/questions/3400/question-custom-gravity-with-wheeled-vehicle.html ) so I add force to counter act that and then additional force to achieve a custom gravity direction.
The biggest hurdle however was to get the tire’s suspension to actually go in two directions. I do traces to check for ground contact and then rotate the vehicle actor accordingly. Additionally I use the Anim Blueprint to rotate the vehicles root bone 180 degrees, which makes the flip almost unnoticeable.
As always the Lego brick models are based on exports from http://leocad.org/
UE4 Not quite Rollcage - YouTube
@Litruv:
I can’t promise that there will be any updates, this thread is mostly for proof of concepts and one-nighters.
greetings,
FTC