v0.31:Combat

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v50.12 · v0.47 · v0.34 · v0.31.25 · v0.28 · v0.23 This article is about an older version of DF. More Info · V

(This page will cover the mechanics of combat - once they're figured out. For now, you may want to refer to Template:Ls, Armor or Weapons)

Combat in Dwarf Fortress is unlike that in most strategy and role playing games. Rather than having hit points, units have a collection of body parts, such as limbs, head(s) and a torso. These have sub parts: limbs have skin, fat, muscle, tendons, bones, nerves and arteries; heads have brains; and torsos have internal organs. Damage to these parts and sub parts causes various negative effects, such as fainting, vomiting, loss of mobility due to bone fractures or nerve damage, and eventually leading to death from organ failure or blood loss. The combat system tries to present a fairly realistic depiction of combat, with several important consequences.

First, combat is very random. Almost anything can get lucky and damage an enemy's vitals, or open an artery causing massive blood loss. Numbers seem to matter, defending against multiple opponents can be difficult even for a decent warrior. Weapons cause damage appropriate to their type. You will often see creatures attacked with impaling weapons such as spears or crossbow bolts die of asphyxiation when their lungs are pierced, while slashing weapons are more likely to open an artery or lop off a limb, and blunt weapons will cause fractures. Some weapons may become stuck in the enemy, if the weapon wielder can maintain control he can continue to do damage and immobilize the enemy, but if the enemy gains control of the stuck weapon, the weapon's wielder will be disarmed.

Reading the combat 'r'eports will give you a gruesome blow-by-blow of the fighting, telling you exactly what each strike did. It is important to note that while most natural creatures have the same sorts of vulnerabilities due to their similar collection of body parts, procedurally generated creatures such as Titans, Megabeasts and Demons may lack these vulnerabilities entirely. Killing a shambling pile of refuse may prove to be a very, very long process due to the fact that it has no vital parts, and killing an adamantium creature may prove impossible using normal means due to the fact that its parts are nearly impervious to damage. When all else fails, a cave-in means certain death for anything caught underneath.

As in real life, combat in Dwarf Fortress is usually chaotic, deadly, and gruesome. Your warriors will not suffer loss of generic hit points, and can not simply rest to regain them. Injuries must be dealt with in an appropriate fashion for healing to occur, broken bones must be set, wounds must be cleaned and stitched up, and for some things such as concussions, you can only wait and hope the victim eventually regains consciousness.

General Observations

• Blunt weapons seem to use density for material strength
• Blunt weapons probably use "contact area" and weapon mass for relative strength

• Edge weapons seem to use the progression Silver->Copper->Bronze->Iron->Steel->Adamantium for material strength
• Edge weapons probably use "penetration size" for relative strength

Mechanics

Based on information in the RAWs and in-game, Toady seems to use real-world physics and material properties for in-game behaviour. Using this as a starting point, we can roughly estimate some of the combat damage mechanics for both blunt and edged weapons.

General Terms

Stress - Force per area = F/A

Strain - Deformation of a solid due to stress = Stress/Young's Modulus

Yield Strength is the amount of stress required to permanently deform (bend) a material (plastic deformation)

Fracture Strength is the amount of stress required to permanently break (rupture) a material

Elasticity (or IMPACT_STRAIN_AT_YIELD in RAWs) is the amount of deformation (bending) that occurs at the yield point

Implications to Dwarf Fortress Combat

Armor Properties

• Material Properties

• Blunt Protection

• Impact yield
• Impact fracture
• Impact elasticity

• Edge Protection

• Shear yield
• Shear fracture
• Shear elasticity

• Item Properties

• Armor Level: Layer number in which armor is worn. Lower numbers will be equipped first, and later numbers equipped if space is available.
• 'Coverage: Some armor covers more of the body than others.

Weapon Properties

• Material Properties

• Common

• Contact Area: Determines the surface area hit by the weapon. Likely in mm².
• Velocity Multiplier: Effectively increases the velocity of the weapon swing.

• Blunt Weapons

• Blunt weapons are all about weapon mass, contact area, and velocity. Apply a large force to a small area for bone crushing goodness.
• Mass is likely material Density times weapon Size
• Momentum is Mass times Velocity
• Any impact must have a conservation of momentum, and thusly, impart the weapon's momentum to the target
• Stress is the Force of the strike divided by the Contact Area

• Material Impact Yield determines the Stress required to dent the armor (likely not used)

• Edged Weapons

• Edged weapons rely on a combination of size, mass, impact area, penetration depth, and velocity

Arena Test Results

• Forthcoming...