Physical constraints between grids. Rotors. Hinges. Pistons.
Paw paw. Well now.. Constraints is too weak. They are so unstable and so..
Any time ive trying to build multigrid vehicles, it is even do not need to start moving, it can explode by itself even if it locked with landing gears..
Any extra percent of force and wheels, rotors, hinges, even pistons, any kind of movably attached grid will just torn out from connections and like elastic will pull back sometimes destroying any of its way.
Is it possible to make for example Hinges have literally fixed relative positions? Not that weird elastic pull silly physical constraints. It shall not break out from its axis, positions of subgrids should be hardly limited or just gets relative zero.
When constrained grid collides with other grids, for example wheels should not that easily get moved beyond their axles even if the suspension force is set to 0. Wheels should easily move only within its limits, but now any such connections under the influence of external grid are simply pulled far beyond their positions. Even that new hinges can well limit vi angles of rotation, but when one part of the hinge moves from other in ten meters away and still trying to work, it is really annoying.