I'm guessing whatever Umberto managed to pull off relies very heavily on the Couatl engine.
Of course, but we would still need some kind of support from the sim itself, they all go together.
In this case, Couatl provides with an entirely new collision detection system that entirely replaces the FSX/P3D default one, which is very limited, and can only do crash "boxes". You might have a glimpse of it if you try to go very close to your plane in Avatar mode: you can't, because the crash box system is not precise enough.
It IS possible to increase its resolution when exporting the model using the normal SDK, but if you do that, the amount of data will grow so much that the memory consumption of the object will go to the roof, and the fps will collapse.
So, we made a new collision system based on an entirely different system, which allows us to define very precise boundaries that allows, for example, to walk inside a very narrow alleys, like the tower internal corridors or the elevator.
But we haven't done "just" that. Precise collision when walking it's just one usage of this technology, but we can also use colliders to trigger events. That's how some of the doors opens automatically when you get close, and how the elevator goes up/down as soon as you get inside.
And, we used this system to also create a new kind of dynamic scenery: by creating custom boundaries (with any shape), we can control the appearance of additional detailed animations only when the user is inside a certain area, with a way more precise control than the simple "distance from the viewpoint", which would waste memory when radius overlaps.
