C.A.T.S.Crunchy Automated Tactical System

Hit Location by Body

Human and mech hit locations from all four facings, derived from presented area.

Presented area, not surface area

Hit location follows the silhouette a shot actually sees. That is not the same as surface area, and confusing the two is the standard error.

The medical rule of nines gives the head about 9%, but it measures skin over the whole body. A roughly spherical head projects far less than its surface implies, so from the front it is nearer 5%. Every figure here is presented area.

Facing is not cosmetic

Turn a target side-on and the table changes twice over:

The clearest single case is a foot. From the front you see its width and it is 1.1% of the target. From the side you see its length, and it becomes 4.1% — several times larger. Torso share falls from 34% to 39% over the same turn.

Front and back present the same silhouette, so their percentages match — but they are different facings, hitting different armour and different things underneath. The tables name locations accordingly.

Human

Human, front view, with each location's share of the presented silhouette.Frontboth limbs presentedHead: 5.4%Neck: 1.5%Chest: 18.4%Abdomen: 16.1%Left thigh: 10.3%Left shank: 7.4%Left foot: 1.1%Right thigh: 10.3%Right shank: 7.4%Right foot: 1.1%Left upper arm: 4.7%Left forearm: 3.3%Left hand: 2.6%Right upper arm: 4.7%Right forearm: 3.3%Right hand: 2.6%5%18%16%10%10%1.5%4.7%4.7%3.3%3.3%2.6%2.6%7.4%7.4%1.1%1.1%Human, back view, with each location's share of the presented silhouette.Backboth limbs presentedHead: 5.4%Neck: 1.5%Upper back: 18.4%Lower back: 16.1%Left thigh: 10.3%Left shank: 7.4%Left foot: 1.1%Right thigh: 10.3%Right shank: 7.4%Right foot: 1.1%Left upper arm: 4.7%Left forearm: 3.3%Left hand: 2.6%Right upper arm: 4.7%Right forearm: 3.3%Right hand: 2.6%5%18%16%10%10%1.5%4.7%4.7%3.3%3.3%2.6%2.6%7.4%7.4%1.1%1.1%Human, left view, with each location's share of the presented silhouette.Leftfar limbs are occludedHead: 10.7%Neck: 2.5%Chest: 20.4%Abdomen: 18.2%Near thigh: 17.0%Near shank: 13.0%Near foot: 4.1%Near upper arm: 7.2%Near forearm: 5.1%Near hand: 1.8%11%20%18%17%4%2.5%7.2%5.1%1.8%13.0%Human, right view, with each location's share of the presented silhouette.Rightfar limbs are occludedHead: 10.7%Neck: 2.5%Chest: 20.4%Abdomen: 18.2%Near thigh: 17.0%Near shank: 13.0%Near foot: 4.1%Near upper arm: 7.2%Near forearm: 5.1%Near hand: 1.8%11%20%18%17%4%2.5%7.2%5.1%1.8%13.0%

How facing changes the answer

FacingHeadTorsoArmsLegs
Front6.9%34.4%21.1%37.6%
Back6.9%34.4%21.1%37.6%
Left13.2%38.7%14.1%34.1%
Right13.2%38.7%14.1%34.1%

Front — hit location table

d100LocationShareTrue areaErrord66
1–5Head5%5.35%-0.3511, 12
6–7Neck2%1.54%+0.4613
8–26Chest19%18.35%+0.6514–24
27–42Abdomen16%16.06%-0.0625–34
43–47Left upper arm5%4.65%+0.3535
48–52Right upper arm5%4.65%+0.3536
53–55Left forearm3%3.32%-0.3241
56–58Right forearm3%3.32%-0.3242
59–61Left hand3%2.57%+0.4343
62–64Right hand3%2.57%+0.4344
65–74Left thigh10%10.33%-0.3345–52
75–84Right thigh10%10.33%-0.3353–56
85–91Left shank7%7.43%-0.4361, 62
92–98Right shank7%7.43%-0.4363, 64
99Left foot1%1.05%-0.0565
100Right foot1%1.05%-0.0566

Worst error 0.65 points against measured presented area.

Back — hit location table

d100LocationShareTrue areaErrord66
1–5Head5%5.35%-0.3511, 12
6–7Neck2%1.54%+0.4613
8–26Upper back19%18.35%+0.6514–24
27–42Lower back16%16.06%-0.0625–34
43–47Left upper arm5%4.65%+0.3535
48–52Right upper arm5%4.65%+0.3536
53–55Left forearm3%3.32%-0.3241
56–58Right forearm3%3.32%-0.3242
59–61Left hand3%2.57%+0.4343
62–64Right hand3%2.57%+0.4344
65–74Left thigh10%10.33%-0.3345–52
75–84Right thigh10%10.33%-0.3353–56
85–91Left shank7%7.43%-0.4361, 62
92–98Right shank7%7.43%-0.4363, 64
99Left foot1%1.05%-0.0565
100Right foot1%1.05%-0.0566

Worst error 0.65 points against measured presented area.

Left — hit location table

d100LocationShareTrue areaErrord66
1–11Head11%10.69%+0.3111–14
12–14Neck3%2.49%+0.5115
15–34Chest20%20.42%-0.4216–26
35–52Abdomen18%18.23%-0.2331–36
53–59Near upper arm7%7.21%-0.2141–43
60–64Near forearm5%5.14%-0.1444, 45
65–66Near hand2%1.77%+0.2346
67–83Near thigh17%16.99%+0.0151–56
84–96Near shank13%12.99%+0.0161–65
97–100Near foot4%4.07%-0.0766

Worst error 0.51 points against measured presented area.

Right — hit location table

d100LocationShareTrue areaErrord66
1–11Head11%10.69%+0.3111–14
12–14Neck3%2.49%+0.5115
15–34Chest20%20.42%-0.4216–26
35–52Abdomen18%18.23%-0.2331–36
53–59Near upper arm7%7.21%-0.2141–43
60–64Near forearm5%5.14%-0.1444, 45
65–66Near hand2%1.77%+0.2346
67–83Near thigh17%16.99%+0.0151–56
84–96Near shank13%12.99%+0.0161–65
97–100Near foot4%4.07%-0.0766

Worst error 0.51 points against measured presented area.

Heavy mech

Heavy mech, front view, with each location's share of the presented silhouette.Frontboth limbs presentedSensor head: 2.8%Upper hull: 24.5%Lower hull: 15.1%Left upper leg: 7.5%Left lower leg: 6.7%Left foot: 2.5%Right upper leg: 7.5%Right lower leg: 6.7%Right foot: 2.5%Left weapon mount: 5.3%Left arm: 6.7%Right weapon mount: 5.3%Right arm: 6.7%3%25%15%7%7%3%7%7%3%5%7%5%7%Heavy mech, back view, with each location's share of the presented silhouette.Backboth limbs presentedSensor head: 2.8%Rear hull: 24.5%Engine deck: 15.1%Left upper leg: 7.5%Left lower leg: 6.7%Left foot: 2.5%Right upper leg: 7.5%Right lower leg: 6.7%Right foot: 2.5%Left weapon mount: 5.3%Left arm: 6.7%Right weapon mount: 5.3%Right arm: 6.7%3%25%15%7%7%3%7%7%3%5%7%5%7%Heavy mech, left view, with each location's share of the presented silhouette.Leftfar limbs are occludedSensor head: 4.4%Upper hull: 26.7%Lower hull: 17.6%Near upper leg: 12.5%Near lower leg: 11.2%Near foot: 6.6%Near weapon mount: 9.9%Near arm: 11.2%4%27%18%12%11%7%10%11%Heavy mech, right view, with each location's share of the presented silhouette.Rightfar limbs are occludedSensor head: 4.4%Upper hull: 26.7%Lower hull: 17.6%Near upper leg: 12.5%Near lower leg: 11.2%Near foot: 6.6%Near weapon mount: 9.9%Near arm: 11.2%4%27%18%12%11%7%10%11%

How facing changes the answer

FacingHeadTorsoArmsLegs
Front2.8%39.6%24.1%33.5%
Back2.8%39.6%24.1%33.5%
Left4.4%44.2%21.1%30.2%
Right4.4%44.2%21.1%30.2%

Front — hit location table

d100LocationShareTrue areaErrord66
1–3Sensor head3%2.82%+0.1811
4–27Upper hull24%24.53%-0.5312–24
28–42Lower hull15%15.06%-0.0625–34
43–47Left weapon mount5%5.33%-0.3335, 36
48–52Right weapon mount5%5.33%-0.3341, 42
53–59Left arm7%6.73%+0.2743, 44
60–66Right arm7%6.73%+0.2745, 46
67–73Left upper leg7%7.49%-0.4951–53
74–80Right upper leg7%7.49%-0.4954–56
81–87Left lower leg7%6.70%+0.3061, 62
88–94Right lower leg7%6.70%+0.3063, 64
95–97Left foot3%2.54%+0.4665
98–100Right foot3%2.54%+0.4666

Worst error 0.53 points against measured presented area.

Back — hit location table

d100LocationShareTrue areaErrord66
1–3Sensor head3%2.82%+0.1811
4–27Rear hull24%24.53%-0.5312–24
28–42Engine deck15%15.06%-0.0625–34
43–47Left weapon mount5%5.33%-0.3335, 36
48–52Right weapon mount5%5.33%-0.3341, 42
53–59Left arm7%6.73%+0.2743, 44
60–66Right arm7%6.73%+0.2745, 46
67–73Left upper leg7%7.49%-0.4951–53
74–80Right upper leg7%7.49%-0.4954–56
81–87Left lower leg7%6.70%+0.3061, 62
88–94Right lower leg7%6.70%+0.3063, 64
95–97Left foot3%2.54%+0.4665
98–100Right foot3%2.54%+0.4666

Worst error 0.53 points against measured presented area.

Left — hit location table

d100LocationShareTrue areaErrord66
1–4Sensor head4%4.39%-0.3911, 12
5–31Upper hull27%26.66%+0.3413–26
32–49Lower hull18%17.57%+0.4331–36
50–59Near weapon mount10%9.93%+0.0741–44
60–70Near arm11%11.21%-0.2145–52
71–82Near upper leg12%12.48%-0.4853–56
83–93Near lower leg11%11.17%-0.1761–64
94–100Near foot7%6.59%+0.4165, 66

Worst error 0.48 points against measured presented area.

Right — hit location table

d100LocationShareTrue areaErrord66
1–4Sensor head4%4.39%-0.3911, 12
5–31Upper hull27%26.66%+0.3413–26
32–49Lower hull18%17.57%+0.4331–36
50–59Near weapon mount10%9.93%+0.0741–44
60–70Near arm11%11.21%-0.2145–52
71–82Near upper leg12%12.48%-0.4853–56
83–93Near lower leg11%11.17%-0.1761–64
94–100Near foot7%6.59%+0.4165, 66

Worst error 0.48 points against measured presented area.

How to roll it

Roll d100. The number rolled is the percentage, so the table reads as what it is: how much of a target each part represents.

Why percentile, when the engine is d6-only

Because the assistant rolls location, not the player. The d6-only rule exists so a person at a table needs nothing but ordinary dice. Location is computed, so it is free to use whatever resolution reads best — and percentages are what a designer actually reasons in.

The d66 column is the fallback for play without an assistant: two ordinary d6 read as tens and units. It is coarser, and the error column says by how much rather than hiding it.

A summed table cannot do this job at all. On 3d6 the centre is 27 times likelier than the tail, so a hand at 2.6% is either unreachable or it distorts everything near it. Whatever indexes a location table has to be flat.

This is the lateral axis only

QuestionAnswered by
FacingWhich side is exposed?Position — it selects the table
LateralWhich part?d100, from presented area
DepthHow far in?Explosions — see Hit Location

So a hit resolves as front facing, left forearm, tier 2 — through the armour into the limb structure beneath. One roll answers the last two.