Should be obvious from names, actually.

If bullet is hitting structure, then structure's ubArmour is modified by structureImpactReductionMultiplier/structureImpactReductionDivisor.

Multiplier/Divisor pair was used probably because someone couldn't use float type tags.

If you need more details, open BulletImpact in Weapons.cpp and HandleBulletStructureInteraction in LOS.cpp in the game sources.

Interesting. According to the old Wiki article (and the file comment), "structureImpactReduction" is the modification of a bullet's efficiency after going through solid objects. Has that changed?

if (PreRandom( 100 ) < pStructure->pDBStructureRef->pDBStructure->ubDensity)
{
	iCurrImpact = pBullet->iImpact;
	iImpactReduction = gubMaterialArmour[ pStructure->pDBStructureRef->pDBStructure->ubArmour ];
	iImpactReduction = StructureResistanceIncreasedByRange( iImpactReduction, pBullet->iRange, pBullet->iLoop );

	iImpactReduction = (INT32) (iImpactReduction * AmmoTypes[ubAmmoType].structureImpactReductionMultiplier / max(1,AmmoTypes[ubAmmoType].structureImpactReductionDivisor));
		
	pBullet->iImpactReduction += iImpactReduction;
...
}

here's the code where it is used in LOS.cpp, HandleBulletStructureInteraction()

sevenfm wrote on Sun, 27 September 2020 15:39

here's the code where it is used in LOS.cpp, HandleBulletStructureInteraction()

Well as I already said this is Chinese to me, so I'll take your word for it.

It would seem this has changed since 3356. Maybe when the "anti-material ammo blows holes in walls" change was introduced?

Anyway.
My problem is that I want to recreate the effect I had in 3356, where 12.7 x 108 mm ammunition went through walls, like in real life.
Now it is stopped by anything, which I'm sorry to say is rather ridiculous: Arulco's brick walls (and even thin concrete) shouldn't be any better than silk paper against such a round. In real life you can even punch through lightly armored vehicles (0.5 cm steel) with it, so obviously body armor shouldn't protect you from that caliber.

So, I've made a new AmmoType and tried to play around with settings I thought would give me back that behavior, but nothing does, anything stronger than a glass pane keeps stopping my bullets. Best thing I can achieve with it is to blow 2x2 m holes in walls, which is kind of over the top, and, till eventually a hole is made, the shooting doesn't affect the people behind the wall either.