To make aircraft gameplay feels like real, it’s important to have true physics of the flight-model and realistic controls. To make tank gameplay feels like real, it is most important to have true physics of the damage model. That’s why we start to reveal details of the tank gameplay in War Thunder from the tank damage model (or DM). To destroy the ground force unit, you have to hit vital components or crew. Armour prevents instant damage to internal components, until it could resist the power of a shell.Ground Forces Damage Model  has the same principles as aircraft DM. Machine is destroyed when key modules or crew members are hit. If armor is hit it will hardly ever destroy the unit.

Here is the collision model of T-34 mod. 1941

KV-1 with it's track destroyed

All armor plates have correct constructive angle of slope and repeat the geometry of the visual model. If several plates had same thickness they can be modeled as one armor group (front and rear turret armor in the given example). Each armor group has its own characteristics (thickness, material, structural strength value )  but all armor is modeled in such a way that it requires high number of penetrations (several dozens or even hundreds) to be completely destroyed. After that the plate will not be taken into account in the DM but usually such number of penetrations will cause destruction of the tank anyway.

Currently all armor has one material - analogue to rolled homogeneous armor  - RHA.

Internal modules simulate all significant machine parts of the tank, their destruction causes the destruction the machine.

Currently tank can be destroyed if :

Ammo rack is destroyed - it can be destroyed by several hits or one hit with a very high damage - usually it means that the shell sill has high penetration capacity after penetrating the armor. In this case there is a high chance of ammo rack explosion - 90% and more.  

fuel tank is destroyed - the conditions are same as above, also fire is possible if the hit brought less damage fire also causes destruction of the tank.

Engine destroyed - the terms are the same, but explosion is not possible, only fire may occur  

Besides that there are several conditions when several important modules are destroyed.:

• tank crew is wounded, no visual effects
• engine/transmission and breach part of a gun are destroyed. Visual effect - fire.

For running gear only tracks are critical, when they are destroyed  tank remains immobile for a period of time.   

Also there are certain penalties  when following modules or crew  members are damaged.

• Engine - reduces power
• Transmission - max speed is reduced
• Train drive -  rotation is slower, if train drive is destroyed turret cannot rotate.
• Gun elevation mechanism - partial damage - lowers gun elevation speed. Destruction - blocks the ability of gun's vertical movement
• Gunner wounded - guidance speed and accuracy are reduced
• Loader -  reloading time is increased
• Driver - slower reaction while driving

Damage model improvements in progress:

• Crew damage model improvements, temporary penalties on certain functions (like killing a driver will cause the vehicle to stop for some time). Crew replacement system
• Weapon damage model detalization (shell self-explosions inside the breech of a damaged weapon, impossibility of shooting in case of damage to the breech part of the cannon etc.)
• Tank machine guns
• Modifications from the ‘defence’ category are being improved for their effects to become more vivid.
• Tank fire extinguishers are being implemented
• Armour protection modifiers depending on its type (rolled or cast steel, medium or high hardness etc.)
• Structural differences in shell types (caps, shapes etc.) and corresponding differences in ricochet angles, ballistics, normalization etc.

We’re sure, that this info was interesting to read even for those players, who prefer aircrafts. Soon we will publish another issue of the Tank Diaries - we have tons of interesting facts to tell!

Tank Marathon will be continued, stay tuned!