After posting the thread about designing chases i thought i would post my rules on mass combat that i am designing and see what you all thought. Think of this system as melding individuals into a swarm that do automatic damage. This system involves a bit of upfront work on the part of the GM as they will need to calculate attacks/exchanges between all potential combat units and even PCs. PCs can also attack the swarm/unit but can only do as much damage as an individual contributes to the unit's HP. Also after mass combat has ended you can take the damage sustained to the unit and kill off a number of individuals equal to the number that would contribute that number of hit points.
Mass combat system basics:
*1 square on combat grid represents 20' X 20' on the tactical "traditional" map and can contain 16 small/medium creatures or 4 large = 1 unit
*All or nothing: For a group to be considered a "unit", they must be similarly equipped with the same arrangements of feats, hps, AC etc as this will really simplify the math (yes there is a fair amount of math involved here).
*Unit stats:
Unit initiative: A unit uses a group initiative
Hit points: Sum of all the hit points for all individuals in a unit, a unit is not dead/nor reduced in stats in mass combat until its HP reach 0 (think swarm)
Attack: (Calculated as follows using the bestiary stats, do not round)
= Average attacker damage X (1 - (Defenders static AC - Attackers attack bonus)/20) + Average attacker Critical damage X (crit range value/20) X (1 - (AC - Attack bonus)/20)
The above calculation is done for the main attack and recorded. It is then repeated for multiple attacks and can be done for specific circumstances like a charge or if the unit is under the effects of bardic music etc. This can become as complicated as you want it to be but i prefer to have at least stats for attacks against each potential defendant on the battlefield for a standard attack, charge and full attack.
note: Attackers crit range value depends on the specific weapon used and is calculated as follows: long swords crit range value = 2 because both 19 and 20 represent potential crits, A rapier would be 3 (18, 19 and 20 are crit threats) and unarmed strikes would be 1)
Unit damage per round: Attack value X # of attackers
Units can do the following in a round:
Move/move = unit moves 2 squares if speed is 20-35' or 4 squares if speed is 40-75' etc.
Move/attack = unit moves 1 square and attacks once (no sneak attack)
Charge! = unit moves twice and ends with an attack with normal charge bonuses but no usual penalties (no sneak attack)
Press-on = unit remains engaged and gets full attack and SA.
I have more rules for formations etc. but i think i have made this far too complicated for this forum already so i will just touch on a few points and end lol...
Cover acts to improve AC and prevents charge
Miss change is multiplied by the Unit's damage per round
units with smite evil or challenge can use these abilities and they have full effect accept that they last only one round.
Spells that remove individuals from combat (sleep fascinate etc) do damage to the unit equal to the number of fully affected members X the individual hit points they contributed to the total.
Anyways thanks for reading!