The cross mark it means you hit something(something active like solder,vehicle),in this mode is turned off.
There are several ways to test the armor:
-the simplest-start the game by creating your game(map with vehicles).Move two tanks/apc somewhere,jump into one
and shoot the other (in the areas you want to test,front armor, rear armor,hull...).Then go into another tank and see type of damage(stuck tank,turret,alarm activated..).So you can test the types of ammo,how many hits in some areas of the tank and more..It's a long process,but it always takes time to test something.Better still if there are 2 players in the game on the opposite sides.
-tough way but more precise.In Predit mode put armor bar to the vehicle.Then when you hit vehicle you can see how many dashes vehicle is losing when it's hit.This requires a bit of knowledge about BF2editor.
!warning: this only work in Predit mod not in PR!
As far as I know,game engine only recognizes type of material which is hit,not the part of the vehicle that is hit.Which means if you hit the tracks,the vehicle will not stop...
greeting
There's no real flame on your screen, it's just magic
