Friday, November 1, 2013

Better Fantasy Armor: Locations, Types, and Bulks

GURPS Low-Tech introduced a new set of rules for pre-modern armor, based on much more comprehensive research than the previous rules. Metal armor became much more expensive and much lighter per point of DR; non-metal armor became somewhat cheaper and much, much heavier. At the same time, a new set of rules for buying armor by location and adding sub-locations like the elbow or shin were added.

I like the new system in concept, but the execution always bothered me. It may be realistic that even minimally protective leather armor weighs a great deal, but it isn't fun. The Low-Tech system is also a bit of a pain to work with: armor weights are given for the torso armor, and head, neck, and limb armor weighs a percentage of the total armor. But fully armoring a character gives an armor weight of 305% of the torso armor weight, which is an annoying number.

So I'm proposing a new Armor Locations Table, a new Armor Table (with the base weight being for the full suit of armor), and new rules on armor bulk to help with armor scaling.

Armor Locations Table

Armor locations in italics are sub-locations of the previous location, and do not need to be purchased separately if the main location is purchased. Sub-locations can also be purchased separately. For example, buying head protection at 10% of the total armor weight includes the skull, face, and neck protection, but a skullcap could be bought for 5% of total armor cost.

LocationCost and 
Hit LocationNotes
Head8%3-5, 17-18
Torso32%9-11Vitals are hit on a 1 on a d6
  Chest(20%)9-10Vitals are hit on a 1 on a d6
  Abdomen(12%)11Vitals are hit on a 1 on a d6
Includes groin
Arms20%8, 12
  Shoulders(6%)8, 12*Roll 1d; on 1-2 this location is hit
  Upper Arms(4%)8, 12*Roll 1d; on 3 this location is hit
  Elbows(4%)8, 12*Roll 1d; on 4 this location is hit
  Forearms(6%)8, 12*Roll 1d; on 5-6 this location is hit
Legs24%6-7, 13-14
  Thighs(12%)6-7, 13-14*Roll 1d; on 1-3 this location is hit
  Knees(4%)6-7, 13-14*Roll 1d; on 4 this location is hit
  Shins(8%)6-7, 13-14*Roll 1d; on 5-6 this location is hit

This is pretty close to the Low-Tech armor table with all values divided by 3 and rounded to make nice values. Some of the values were adjusted to make them a little less painful: per the by the low-tech rules, long gauntlets that fully cover the forearm end up weighing an absurd amount.
I made a big edit to this table, after realizing I'd rather have the numbers be multiples of 4 than multiples of 5. There's a lot of halving and quartering in the math, and all those 1.25% values were getting untidy. Even so, I'm keeping the face at 3%, since it makes the math for the face sublocations tidy. There's always trade-offs.  

Simplified Face Sub-Locations

There are 6 sub-locations on the face: jaw, cheek, ears, nose, eyes, and brow. Each one can be separately protected at the cost and weight of 0.5% of the base armor. Eye protection gives No Peripheral Vision. Ear protection gives either Hard of Hearing or removes -2 in penalties to target the armor gaps in the head. If the face is targeted and the target is wearing partial face protection, roll 1d: if the roll is less than the number of protected locations, the armor protects.

Armor Table

The following table shows armor cost and weight, per point of DR, for a full suit of armor.
Armor TypeLbs/DR$/DRNotes
  (Cloth, Silk)
-2 DR vs Impaling and Piercing
  (Leather, Hardened Leather)
-2 DR vs Impaling and Piercing
  (Wood, Straw, Paper, Cane)
  (Lamellar, Brigantine)
10$250-2 DR vs Crushing
-2 DR vs Crushing
  (Segmented Plate)

Any type of armor can theoretically have any amount of DR, but see the limits on bulk below. Individual variations of an armor type (such as scale versus lamellar versus brigantine) should have modifiers to their cost and weight that I've covered in another post.

Using these two tables should be pretty simple: choose an armor type, an amount of DR, and coverage, and multiple them together. For instance, a long-sleeved mail hauberk that covers all of the arms and torso (55%) and provides DR7 costs ($400 * 7 * .55) $1540 and weighs (6 * 7 * .55) 23 lbs. A head to toe suit of iron plate that provides DR9 costs ($500 * 9) $4500 and weighs (7 * 9) 63 lbs. A horn helmet that covers the face and skull and provides DR4 costs ($150 * 4 * .08) $48 and weighs (12 * 4 * .08) ~4 lbs.

Historically, armor wearers tended to optimize their armor: putting thinner armor on the inside of the arms or neglected the back of the armor. As two quick guidelines, armor with the weak limbs modifier halves the armor DR on the back of the arms and legs, reducing the total cost and weight by 11%. Armor with the weak back modifier halves the DR on the back of the torso, reducing the cost and the weight of the armor by 8%. Another arguably real-world optimization would be reinforcement over the vitals. Doubling DR for hits to the vitals only increases armor cost and weight by 6% (3% each for the front and back).

Armor Bulk

Thicker armor is bulkier armor, and bulky enough armor imposes a DX penalty. Larger creatures can tolerate more bulk; smaller creatures can tolerate less bulk. So while a pixie is strong enough to lift enough bronze to make a suit of 2mm thick plate armor, armor that thick wouldn't give him space to bend his elbows (being roughly equivalent to armor that is 12mm thick on a human).

The maximum thickness of armor that a person can wear without a DX penalty depends on their SM, and is shown on the table below. Similarly, a larger creature can wear a thicker layer of armor beneath another piece of armor without having their DX penalized.


So an SM-6 pixie can only wear the thinnest of armors; a normal human can wear Heavy armor and layer it over Thin armor; and a SM+2 Ogre Barbarian isn't penalized by jousting armor and could wear a suit of thin mail under it.

Each armor type has its own maximum DR for each category of bulk. The DX penalty for wearing armor that is too bulky is -1 per level of bulk: an SM-4 leprechaun wearing jousting plate is at -3 DX.
The bulk penalty only applies to locations that are at least 50% covered by armor, just like the layering penalty.

ThinLightMediumHeavyJousting Massive

Again, this should be straightforward. DRs are intentionally increased from normal GURPS ranges because the armor is generally lighter per point of DR and because (in my experience) dungeon fantasy games tend to be high lethality, so increasing DR is really helpful. A knight or samurai in heavy armor (with padding beneath) has DR in the 9-13 range, and is basically immune to sword blows from attackers.

Joints and Heavy Armor

As an optional house rule, anyone who wears the thickest safe armor on their joints (shoulders, elbows, knees, abdomen, and neck) suffers a -1 penalty to DX, which can be mitigated by leaving big gaps in the armor - attacks through the armor chinks in those locations get at +2 bonus. Wearing thick armor on the hands gives the Ham-Fisted 1 and Bad Grip 1 disadvantages.

Design Notes

Cloth armor, at low DRs, is affordable for both weight and cost. It rapidly becomes too thick to wear, well before it becomes good for anything other than avoiding knives and incidentally damage.

Bone armor is always bulky. It's not desirable armor for metal-working cultures, but that models historical trends.

Mail is lighter than plate per point of DR, which makes sense, because almost all metal armor should be equivalent. Mail's flexibility and vulnerability to crushing damage mean that plate is still better armor for those who can afford the expense and weight.


  1. SJ Games official errata now states that the neck is part of the head:

    So I'm in good company there.

  2. I think the SM +0 line of the bulk table must be wrong, as it is inconsistent with your text elsewhere.

    "Each armor type has its own maximum DR for each category of bulk. The DX penalty for wearing armor that is too bulky is -1 per level of bulk: an SM-4 leprechaun wearing jousting plate is at -2 DX."
    -3 per the table.

    It should probably be easier to underlayer flexible armor, at least around the joints.

    More generally, bulk *assumes* that there are joints. If on has a breastplate, helm, and greaves (to pic an arbitrary example), there are no joints for the bulk to foul up, only excessive weight.

    Tangentially, I think if GURPS is going to move towards heavier DR values for the sake of realism, it needs to open up the chinks and joints hit location a bit.

  3. Good catch on the table; I'll fix the text.

    Bulk does assume there are joints, which is normally a reasonable assumption. I'd modify the Low-Tech layering rule and say that bulk doesn't count if you have less than 1/2 the armor location covered. If you have your chest covered with 10mm of steel, your arms are still constricted in their range of motion even if there isn't another 10mm of steel rubbing against them.

    You can only ever underlay flexible armor. At some point I'm going to add rules for arming garments and voiders, with some kind of note that (at least for SM0 cases), having thin flexible armor at the armor voids doesn't count as layering or increasing bulk. I want there to be rules for what happens when someone wears a Giant Spider Silk arming doublet with mithril voiders, and it's vaguely annoying to me that Low-Tech doesn't provide the rules for that though it should have been able to.


Note: Only a member of this blog may post a comment.