Thomm has it right While it is absolutely true that CMx1's armoring modeling is far, far more detailed and scientific than other games to this day (CM:SF excepted), it still basically boiled down to abstracted "dice rolls". The difference between CMx1 and other games is that the values going into the "dice rolls" were very carefully calculated based on scientific formulas, broad ranges of variables, and lots of situational input. The early Steel Panthers, for example, was more-or-less rock/paper/scissors. If you had a gun with a value of 9, and you hit a tank with an armor value of 5, you had x chance of damaging and y chance of killing.
A really good example of the difference is in the modeling of damage. Here's how the two games work:
CMx1
A hit is registered (probability based decision which part of vehicle struck) and it is determined if the round does any damage based on conditional circumstances (relative angles, armor type, armor thickness, etc.). If damage is achieved then it is determined based on the strength of that hit (amount of HE in the shell, kinetic energy, etc) and some other factors (e.g. a vehicle might be tagged as being prone to brewing up, while another one prone to catastrophic armor shattering). This assessment may be quite detailed, but in the end it basically amounted to dice rolls.
CMx2
The shell trajectory, including the angle of the shell at the time of impact, is tracked in detail. Where it hits in the 3D representation is where it hits in the underlying data for that vehicle. Shell looks like it hits the front left corner of the front of the mantlet? That's exactly where the hit is registered. The exact angles of the shell compared to the armor are taken into account, the properties of that specific portion of the vehicle (thickness, resistance level, type of armor, etc.) are used for detailed scientific calculations to determine what sort of damage, if any, is achieved. Damage is assessed based on what could possibly be damaged by that hit. A hit to the engine compartment isn't going to knock out the bow MG, for example. A hit to the right side that doesn't penetrate may in fact knock off the radio antenna, thus disabling the radio, but a hit to the front right track wouldn't, though it would disable and/or damage the right track. For modern warfare it means a hit that clears off a specific block of ERA (explosive armor) is now free to be hit again, but the subsequent shot must hit that same place. Likewise, a hit that strikes the armor next to ERA blocks isn't affected by them. That sort of thing.
To put it another way... CMx1 makes a pretty good, but abstracted, guess as to what should be damaged while CMx2 instead figures things out very precisely.
Now, what's the difference between the two, one might ask, in terms of gameplay? Well, if you don't care about realism then the answer is "not much". If you do care about realism then the difference is rather significant. Perhaps not quite as much of a difference between CMx1 and CMx2 as there is between CMx1 and Panzer General, but still there is a noticeable difference. It also is MUCH easier from our standpoint because we don't have to go around fudging code when game results appear unrealistic. We had to do that a lot on CMx1 (remember the raging debates about Tiger 1 mantlet thicknesses, anybody?), but haven't had to so any of that stuff for CMx2.
Steve
