Research:Combat

Attack swing
Swing is the amount of time the weapon is held back for attack. The damage range of a weapon is directly related to how long the attack key is held. An instant click will result in minimum stated damage, while waiting until the attack wind-up animation is fully complete will result in maximum stated damage.

For the player:

For NPCs and creatures:

Comments
Weapon strength scaling does not use existing scaling GMSTs, and hand-to-hand does not exhibit any strength scaling. MCP uses fDamageStrengthBase + 0.1 * fDamageStrengthMult * actor.strength for weapon scaling.

Comments
The unaware check is only calculated correctly for projectile attacks. Due to either a design decision or bug, it doesn't apply to melee attacks, but it seems likely to be an design bug. It is recommended to implement it for all cases.

Elemental shield
Elemental shields are similar to a thorns effect, causing damage to the attacker.

Elemental shields do not stack, each effect instance is rolled separately.

Blocking with a shield
On enemy hit

Comments
The enemySwing variable is effectively how much the enemy has charged their attack. It seems to be uniform random and is not based on weapon damage. The other thing of note is the playerTerm bonus. The fBlockStillBonus GMST is not used in vanilla Morrowind (the multiplier is hard-coded), but is used in OpenMW. Unexpectedly, this bonus is still given if the player is moving backwards or strafing, only moving forward will negate it.

Bodypart hit chance
Note that you still take unarmored class hits to the shield arm if you don't have a shield equipped. This includes when the actor is holding a 2-handed weapon.

Comments
Note that projectile attacks cannot crit, but they do make the critical hit sound, as the sound code is separated.

Comments
It appears that the volume of the armour hit sound is proportional to the enemy attackSwing.

Comments
Hitstun is the actor state, with accompanying animations (Hit1-5 or SwimHit1-3) and movement restriction that occurs when the actor is hit. Hitstun prevents movement during its animation, while still allowing turning, crouching and jumping. It also prevents initiating new attacks or casting, but allows attacks (including releasing the attack button to strike) or casting to complete.

Comments
This occurs on the same conditions that cause the weapon "miss" sound, as well as hits. Uses rawDamage, not mitigated damage. Should be evaluated after the attack is complete, as it may break the weapon.

Determining armor class
Item armor class:

Armor rating
For NPCs or the player:

For creatures:

Comments
Without fixes, if an actor has no armour equipped at all the game would return an armour rating of 0, ignoring any unarmored skill. Similarly, creatures would always have zero rating, even ones that have active shield spells. Note that elemental shield spells do not contribute towards armor.