GURPS-to-ACKS: Unit Building

GURPS-to-ACKS: Unit Building

ACKS, including ACKS II, focus on advancing the characters from adventurers to conquerors and then to kings. The system devotes a lot of attention to domain management and mass combat, because how else would you do the C and K parts of ACKS? Despite GURPS and ACKS being built on very different frameworks, the underlying simulationism paradigm makes them surprisingly compatible when it comes to non-combat stuff, such as domain management. (Of course, you can remove the simulationism from GURPS, but why would you?) ACKS domain management rules seem to be usable almost without any changes in GURPS, but I will explore that topic in more depth in the future. However, mass combat as it is described in Domains at War: Battles and Domains at War: Campaign does require some changes. There are two ways to go about it: to work out how to derive ACKS unit statistics from GURPS stats, or to rework D@W:B to use GURPS resolution mechanics. In my opinion, the first option is the way to go here, even though you technically have to learn two systems, which is something many will balk at. However, D@W:B is actually rather simple, but at the same time deep and robust - learning it doesn't require that much effort. So, let's outline the work we have to perform here:

We have to derive the following:

- Unit Movement Rate/Formation

- Unit AC

- Unit Hit Dice

- Unit Hit Points

- Unit Attack Throw

- Unit Number of Attacks

- Unit Morale

Outside of the unit stats, we will have to think about statistics of officers - strategic ability, leadership ability, and morale modifier.

I will not touch the Battle Rating, at least not yet. If we cover all of the above, we will be able to resolve a GURPS mass combat using the rules from D@W:B. This covers only this basics - no heroes and no magic, but I will try to adapt these rules as well, if this effort is successful, of course.

Also, I have to clearly say something before I start just to avoid misunderstandings. This is not meant to be a 1-to-1 conversion of GURPS to ACKS or the other way around. If you apply these guidelines to normal combat, they probably will not work. Some things will get lost in translation, and I will have to abstract some GURPS stuff. This is going to be a conversion between two different abstractions, as D@W:B abstracts some ACKS stuff as well. Many of the minute details that GURPS combat may be concerned with just do not matter on the mass scale. The goal here is to be able to use D@W:B rules as a substitute for GURPS Mass Combat, because I'm not satisfied with the latter. This will only be useful for fantasy games - this will not work for modern or sci-fi games! The end result probably will differ from the existing ACKS stats - and that's okay, because if you make all your units using this approach, you will still have consistent stats. Just don't mix them together.

With the disclaimer out of the way, let's begin.

UNITS

Unit Movement Rate/Formation

Movement Rate is based on the creature's movement rate. A rate of 60' results in 1/2/3, a rate of 90' results in 2/3/4, and a rate of 120' results in 2/4/6. Formation depends on weapons used and, sometimes, on the nature of the creature itself.

120' seems to be the standard for a unencumbered human. I suggest doing the following:

Move 1-2 (after encumbrance): 1/2/3 - that's the 60' equivalent

Move 3-4 (after encumbrance): 2/3/4 - that's the 90' equivalent

Move 5-7 (after encumbrance): 2/4/6 - that's the 120' equivalent

Formations will remain the same as they are in D@W:B.

Unit AC

ACKS, unlike GURPS, doesn't have active defenses. Armor Class, according to ACKS II Revised Rulebook, "is a measure of how challenging it is to damage your character. An unarmored character of average attributes has an AC of 0."

Thus, this represents something of a combination of Active Defenses and DR, if we are to use GURPS terms. An unarmored character of average attributes in GURPS has no DR and has a Dodge score of 8. So, we will use this as a baseline. However, to get a sense of the various AC values, I will have to consult the ACKS armors.

There are five basic armor types: leather (+1 AC), scale (+2 AC), chain (+3 AC), lamellar (+4 AC), and plate (+5 AC). If we look at the extensive armor table in GURPS Low-Tech, we will see that this roughly corresponds to AC = torso DR/2, rounded up.

Shields in ACKS also add +1 to AC, and I think it's reasonable to keep it that way too.

But what about the active defenses? ACKS doesn't have Parry, but AC does benefit from high DEX. I suggest representing it with a function of Dodge. For example, AC gets a bonus of (Dodge - 8)/2, rounded down; minimum 0. You can't get a penalty from low Dodge.

Thus, the formula is the following: AC = torso DR/2, rounded up + 1 if shield + (Dodge - 8)/2, rounded down. Minimum 0.

I think this should work fine for human-sized creatures, but it may produce values that are a bit off for monsters. If that's the case, adjustment will be in order.

Unit Hit Dice

That's probably the most difficult one. Hit Dice are very abstract. This is something equivalent to a "character level." Hit Dice are used to determine hit points and attack throws for monsters. In GURPS, HP are based on ST, and to-hit rolls are all based on DX. Most humanoids in ACKS have 1 HD, sometimes with a modifier. What makes things even more difficult is that HP also are somewhat abstract. I don't think there's a way to properly translate the concept of Hit Dice, so I will come up with a different measure.

    HD = 1 + (ST - 10) / 5

This way, most of the humanoid creatures will have HD almost identical to those in ACKS. Larger monsters will have different values, but as long as we're using a consistent way to calculate everything, things should be fine.

Unit Hit Points

The ACKS formula for this is HD x number of creatures / 15. We keep it.

Unit Attack Throw

This is another tough one, because ACKS is a d20 system, while GURPS is GURPS. Probabilities just are not going to be the same, but that's not actually my goal. I just have to find some metric and approximate the attack throw value. In GURPS, to-hit rolls are based on weapon skill that is in turn based on DX. Most of the "regular" troops in ACKS hit on 11+ or in its whereabouts, while powerful monsters sometimes hit on 4+, or even -4+.

    Attack Throw = 17 - HD - (attack skill/2), rounded up

It seems like this should work.

Unit Number of Attacks

The ACKS formula is (number of creatures) x (creature’s number of attacks + creature’s cleave factor) x (average damage) / (size factor x 4.5)

GURPS and ACKS are quite different in this regard due to GURPS combat being played out in 1-second rounds. Thus, here we have to approximate how the creature would work in ACKS. The guidelines are as follows:

- If a creature has natural weapons (claws, horns, fangs, stingers, etc.), then creature's number of attacks is equal to the number of said natural weapons, if this is a creature "suitable for combat." For example, a griffon would have three attacks (2 claws + 1 beak), while a horse would have 1 hoof attack, because it isn't really a combat monster.

- If a creature uses manufactured weapons, then the number of attacks is equal to the number of weapons held. Thus, a regular human soldier would have 1 attack, while a four-armed bone golem would have 4 attacks.

Cleave factor is a mechanic unique to ACKS, and it works well there. GURPS has no such thing by default, but since the cleave factor is based on HD, we just leave it as is.

Size factor, obviously, depends on the creature's size. Fortunately, there is a Size Category table in ACKS that has real world measurements, so we can more or less easily convert the sizes. "More or less" is because the breakpoints between the categories are different. Thus, a SM+1 GURPS gnoll that is 7 feet tall is a Man-Sized creature in ACKS, but a SM+1 GURPS ogre that is 9 feet tall is a Large creature in ACKS.

Small: 2' or less

Man-Sized: 8' or less

Large: 8' to 12'

Huge: 12' to 20'

Gigantic: 20' to 32'

Colossal: 32' or more

Average damage probably needs no adjustment. For the sake of simplicity, let's ignore the wounding multipliers. Also, I have to remind you that by default, swing-based damage in GURPS can get ridiculous with high ST, so I highly recommend using the Reduced Swing Damage rules.

Unit Morale

Morale isn't a thing in GURPS as a stat. Just assign an appropriate value. In ACKS, morale ranges from -4 (for a monster that virtually never fights) to +4 (for a monster that virtually never retreats or surrenders). Mindless monsters never roll morale.

Examples

All right, let's try making an infantry unit of 120 spearmen. The relevant stats are here:

    ST 10

    Spear (10): 1d imp

    Light Scale Armor (DR 3)

    Medium Light Shield

    Move 4

    Dodge 7

    Unit Movement Rate/Formation: 2/3/4 (FF)

    Unit AC: 3

    Unit Hit Dice: 1

    Unit Hit Points: 8

    Unit Attack Throw: 11+

    Unit Number of Attacks: 120 x (1 + 0.35) x 3.5 / (60 x 4.5) = 2.1 = 2

    Unit Morale: -1

    We ended up with something between 120 Light Infantry B and 120 Heavy Infantry C. I guess this is medium infantry then. Also, using this approach, humans will typically have 8 uhp, not 6.

Now, let's try making 60 ogres. The relevant stats are here:

    ST 18

    SM+1 Round Mace (10): 3d+1

    Medium Leather Armor (DR 2) + DR 2 (tough skin)

    Move 5

    Dodge 8

    Unit Movement Rate/Formation: 2/4/6 (IF)

    Unit AC: 4

    Unit Hit Dice: 2+2

    Unit Hit Points: 10

    Unit Attack Throw: 10+

    Unit Number of Attacks: 60 x (1 + 0.65) x 11.5 / (40 x 4.5) = 2.1 = 6

    Unit Morale: +2

    These ogres, when compared to ogre light infantry from D@W:B, are faster, but have fewer HD and HP. They have 6 attacks that hit on 10+, while the ACKS ogres have 4 attacks that hit on 6+. Is that okay? I'm not sure, but it probably is.

OFFICERS

With units out of the way, we also need the officer statistics. In the most basic case, we need their strategic ability, leadership ability, and morale modifier.

Leadership Ability

In ACKS, this is equal to 4 plus Charisma modifier, and a +1 bonus for Leadership proficiency. The maximum leadership is 8. Monstrous officers without Charisma scores have leadership ability of 3 + 1 per 4 HD, rounded down.

I suggest the following approach:

    Leadership ability = Leadership skill / 2, rounded down

For monstrous officers, just give them at least a point in Leadership! Certain intelligent monsters would be able to get a decent leadership ability even when defaulting the skill.

Strategic Ability

In the context of battles, it seems to only affect initiative, but it also plays an important role in Domains at War: Campaigns. If I were shortsighted, I'd just say "use the Strategy skill", but if I want to adapt the Campaigns rules in the future, I have to bring things into the ACKS range of -3 to +6.

Strategy is a skill in GURPS that defaults to IQ-6.

I suggest the following:

    Strategic ability = Strategy skill / 2 - 3, minimum -3, maximum +6.

Morale Modifier

It seems that the morale modifier can also be based on the Leadership skill. I suggest the following:

    Morale Modifier = Leadership skill / 3, rounded down

And that's it. This should cover most of the basic stuff, but not heroes and magic - those concepts will require additional thoughts later.