The idea is that the diagonals are strongest loaded in tension.
So if you know which direction the loads are coming from,you can design to suit.
Sometimes a space frame will be made not as strong as possible,
on the ends,to absorb energy in a crash.The closer the structure
gets to the driver,the stronger it gets.Progressive stiffenss.
In a serious crash,the car will bend.If it bends a little more
in the right places,it can save the driver from injury or death.
Bending too much in the wrong place,only makes the situation worse.
Other people just build everything heavy,
rather than understanding what is really needed.
