Modelling armour in RPG’s is a finely balanced affair. At once the mechanics have to support what’s known about armour and yet remain playable. For instance:
- Armour doesn’t slow one down like to the degree that fictional films portray lumbering knights
- It does make one tire far quicker since heat cannot escape the body as efficiently
- Heavy mail and plate will turn aside almost all slashing attacks
- Targeting the less armoured points will likely require called shots, or a greater abstraction that leads to less distinctive effectiveness between armour ‘suits’
- Massive cost of armour
- Full metal armour either includes, or requires, full under-padded suits which are themselves light armour
Taking into account just the above considerations necessitates a choice:
Detail & crunch,
or Abstraction & vagaries.
Armour is also inextricably linked to the damage mechanics of an RPG rule-set.
To use the DnD armour system as a benchmark, all it really does is make it a bit harder to have a chance to inflict random damage. It slows the character and with the heavy armours a dextrous character is actually better off without. This makes armour pretty much a waste of metal. However, if character dexterity’s stay in the average to above average range (+0 to +3) then heavy armour will remain somewhat effective – however armour doesn’t make it harder to have a chance to inflict damage. It flat out reduces the ability of an attacker to inflict damage at all. That’s where the main challenge comes in.
In simple systems this is all just abstracted away. For crunch this needs detail. If you want to actually have a functional difference between a double-mail hauberk and a suit of half-plate and mail then you require an armour & damage system that has enough granularity to reflect the difference.
A double mail hauberk is very heavy, has fantastic slashing protection, good puncture protection and good crushing protection. To penetrate this armour an average attacker would have to deliver a near perfect blow with a dedicated armour piercing weapon. However, the hauberk does not cover the feet, ankles, lower leg, hands, face, throat, etc. So most attackers will be trying to strike these areas. The defender in the hauberk will realise this and it will give them a tactical advantage in that they need not defend with full energy their entire body because the risk of damage is only significant enough to defend the face, hands and feet. Tactically and systemically it makes the combat a little more different than attack, defend, attack, with a tempo like an old kung-fu movie. Knowing that your attacker can only really injure you in three places means you have a lot more energy to move towards offense than, say, you were wearing only a leather cuirass protecting your torso.
Given these ideas of how fighting in and against armour functions it means any abstractions need to weigh these details in to the final decision. The final litmus test is that armour is actually worth wearing – because if it’s not, then it would never be kept and sold past the realisation of it’s ineffectiveness.
The only real exception to this is the armour that is culturally more significant than it is utilitarian. And that kind of armour is very rare throughout history.
Now in particularly stagnant cultures, like traditional fantasy elves, they’d have very fine armour that a craftsman could spend a century making but has not been improved in design since they so rarely war. Against cultures whose armour is tested every summer for the same duration they elves would be far behind in terms of design. It’d be like the most gorgeous suit of armour from the iron age is suddenly compared to the most recent but ugly development from the late 14th century Milanese armourers (who’d tempered the metal like spring-steel). Pressures of constant war push technology further than placid supposed superiority. This concept means that the classic elves would have beautifully made and functioning armour that is ‘antiquated’ in design and likely materials – luckily they can magic their way out of it in most settings.