Another Attempt to Fix Throwing

[Pursuivant]

For various reasons, the GURPS throwing rules are crocked.

While they get throwing speeds approximately right, assuming that maximum distance is achieved in just one second, the damage results compare very badly as compared to the damage the same missile would deliver at the same speed if it was dropped.

That is, a 5.5 oz baseball (~3 or 6 HP in GURPS terms) delivers just 1d-3 HP of damage when hurled at 100+ mph (49 yps) by a ST 12, Throwing skill DX+2 human, but 1d or more damage when dropped at a speed of 49 yps.

There is also the fundamental fact that anything that boosts a missile's speed also increases the damage it inflicts. Assuming an optimal launch angle, you cannot increase a missile's range without increasing its speed and you can't increase its speed without increasing the damage it inflicts. Even so, air drag will eventually slow missiles to terminal velocity; even missiles which start off fast will, assuming they don't hit the ground first, eventually inflict no more damage than they would if they were falling at terminal velocity.

This means that GURPS rules that just boost throwing distance without boosting throwing damage are wrong. This is backed up by plenty of evidence that trained throwers can throw harder and farther than untrained people.

After crawling through kinesiology papers, books on sports physics, and sports training web sites, and after comparing weight vs. distance ratios for world record throws, I've discovered that throwing distance decreases linearly as a function of mass. Punch & Pulver almost got the GURPS 4E throwing rules right, but they made the mistake of using a power curve rather than a linear function.

This is my proposed fix.

1) Make Throwing damage another special form of Collision. Those rules deliver relatively accurate results as compared to KE predicted by Doug Cole's formula.

Assuming 3+1 or 6+2 HP per pound makes it easy to multiply speed in yards/sec x HP x /100, at least for objects from 1-10 lbs.

2) "Basic Throw" in yards is equal to BL/2. This represents the maximum distance you can throw an item on a relatively flat trajectory without any special skill or effort.

Note that this is the combat throwing speed in yards/sec for quick, flat trajectory throws which still allow you to defend yourself. It can be improved with Extra Effort, skill, various forms of Committed Attack and All-Out Attack, and various sports or hobby skills.

3) Increases to ST increase BL to determine Basic Throw. That is, every +1 to ST boosts BL by n+1^2/5 lbs which boosts Basic Throw by +(n+1^2/5)/2 lb.

4) Humans get the greatest distance when throwing an object which weighs approximately 0.33 to 1.5 lb. Conveniently, that's the weight of most balls used in throwing sports.*

5) BL Ratio to Basic Maximum range is as follows:

BL Ratio	Basic Maximum Range
x0.017	1
x0.025	0.8
x0.038	0.65
x0.05	0.55
x0.075	0.5
x0.10	0.4
x0.13	0.35
x0.25	0.25
x0.38	0.2
x0.75	0.15
x2	0.1
x6	0.05

The exception is that objects with a mass of less than 1/3 lb, or a density of less than 1 g/cm^3 (i.e., anything that would float on water) have limited throwing range regardless of ST. Likewise, very bulky or inconveniently-shaped objects (e.g., open umbrellas) also have reduced range as determined by the GM. No hard rules are possible given the complexities of air drag vs. velocity. GURPS Critical Reynolds Numbers would be about as popular as cholera.

As an example, these are the modified maximum ranges for missiles thrown by a person with ST 10.

	

Pounds	Yards
0.33	20
0.5	       16
0.75	13
1	        11
1.5	       10
2	         8
2.5	         7
5	        5
7.5	        4
15	       3
40	       2
120   	1

6) Allow lots of optional rules to boost range by throwing at a higher trajectory in order to achieve range rather than speed. T-Bone's Games Diner and his GULLIVER rules are a great place to start.

7) When throwing for pure range with a throwing sport (e.g., Combat Sport (Javelin)), allow critical successes with a skill roll to give an additional +1 to ST (+3 total).

Additionally, the player can roll the dice again. Success means that they get another +1 bonus to ST, or +2 if they their margin of success is 4 or better. Another natural critical success gives another +3 bonus and allows yet another roll, and so on.

This means that there's a ~1:50K chance of hitting a second critical success, a ~1:10M chance of getting a third, and so forth. These bonuses to skill only improve range, not damage and represent luck, favorable atmospheric conditions, tailwinds, and other factors which contribute to world record throws.

This gives realistic characters with realistic skill levels only marginal chances at approaching or beating world records while not crippling super-strong cinematic characters who should be able to throw objects at the speed of bullets.

Using these rules, a ST 12-13 person with Throwing DX+2 or better can consistently fire baseballs at 80-90 mph, while a ST 10 untrained person can only manage an anemic 50-60 mph hurl.

With a bit of Extra Effort and a high Sport (Baseball) and Throwing skills, major-league level pitchers can regularly manage 95+ mph fastballs. Unless the GM allows extreme levels of ST and very generous Extra Effort rules, they also have trouble getting past 105 mph, which appears to be the approximate physiological limit for how fast humans can throw.

8) These rules add an extra calculation to already complex rules, but they make it very simple for a GM to "run and gun" by just eyeballing throwing distance. Without all the chrome and blinky lights, it's just 1/2 BL x some fraction = maximum throwing distance.

With the BL table and a homebrewed speed/damage table for the sort of weights that characters are likely to drop or hurl, it gets even easier.


* Not so coincidentally, it also matches up with the preferred mass of rocks used by Paleolithic hominids for hunting. Throwing ability, along with superior endurance running and color vision, allowed our distant ancestors to survive on the hostile East African savannas. By comparison other primates suck, managing just 30% of human throwing force.

Humans are hard-wired to throw, and there's some evidence that throwing ability led to brain growth, social skills**, and language. That's something to keep in mind the next time you see a toddler flinging their Spaghetti-O's at the dog. Don't call it "making a mess," it's predator practice!

It's also worth mentioning that pound for pound female humans can throw just as hard as males as long as they get proper training. So don't say "you throw like a girl," say "you throw like a chimpanzee".


** This might explain why jocks tend to be popular and most nerds can't throw.

[kirbwarrior]

Originally Posted by Pursuivant

assuming that maximum distance is achieved in just one second

I don't think that's an actually assumption but a gamism thing so that a throw can be done in combat. Bullets and arrows don't travel their full distance in a second, either, yet you can shoot anyone on your turn.

[Pursuivant]

Originally Posted by kirbwarrior

I don't think that's an actually assumption but a gamism thing so that a throw can be done in combat. Bullets and arrows don't travel their full distance in a second, either, yet you can shoot anyone on your turn.

It's a simplification, but it's also the only way to get anyplace close to real throwing speeds. With a few house rules on long-distance throws the RAW rules could sort of work to get realistic distances, although damage based on kinetic energy would still be off.

If you still wanted to base damage based on a character's Thrust, it would make sense to just use thrust unmodified by weight/BL ratio and assume that differences in actual missile velocity vs. weight are evened out by reductions in range. Heavier missiles don't fly as far or as fast, so extra damage from their increased mass is canceled by their reduced velocity.

It doesn't work that way IRL, but unless you have a character flinging missiles at ballistic speeds the disparity between mass and velocity wouldn't be that unreasonable.

[kirbwarrior]

Originally Posted by Pursuivant

It doesn't work that way IRL, but unless you have a character flinging missiles at ballistic speeds the disparity between mass and velocity wouldn't be that unreasonable.

Maybe it was back in 3rd but I distinctly remember rules for converting high enough velocity throws into piercing, letting you literally throw bullets.

As for thoughts on your proposed fixes, I absolutely agree that increases to throwing range should boost damage and vice versa (I don't remember if Throwing Art lets you throw further). Also, some of it seems focuses on 'realistic humans' and like my comment above, I don't know if it applies well to supers, giants, pixies, etc.

[Pursuivant]

Originally Posted by kirbwarrior

Maybe it was back in 3rd but I distinctly remember rules for converting high enough velocity throws into piercing, letting you literally throw bullets.

GURPS 4E gives the GM the option of converting crushing damage from thrown objects to other types of damage.

For characters with ST 15 and above, it wouldn't be unreasonable to convert damage from small, dense missiles into the appropriate form of piercing damage.

Originally Posted by kirbwarrior

I absolutely agree that increases to throwing range should boost damage and vice versa (I don't remember if Throwing Art lets you throw further).

In RAW, Throwing Art works like a super-version of Throwing. If I read it right, it not only substitutes for Throwing and all Thrown Weapon specialties, but also allows you to effectively hurl very light or oddly-shaped missiles.

As an optional rule, Throwing Art could allow you to ignore the effects of air resistance, turning normally harmless objects like playing cards or ping-pong balls into lethal weapons.

Originally Posted by kirbwarrior

Also, some of it seems focuses on 'realistic humans' and like my comment above, I don't know if it applies well to supers, giants, pixies, etc.

Giants and supers do very well under these rules since their massive ST allows them to hurl heavy objects long distances. Giants can easily throw boulders and brick-type supers can easily toss cars.

Since damage from thrown objects is based on collision damage, big heavy objects can inflict massive damage. In fact, unless you scale up weapon and unarmed damage for such characters, throwing a heavy object might be their most damaging attack.

At the other end of the scale, tiny creatures suck at throwing, which is realistic.

When I was researching this mod I was able to get info on throwing distances for grade school kids at almost all ages from K-12. Using a GURPS mass to ST conversion, U.S. CDC mean weights for boys, and expected performance levels by age from travel league baseball sites and biokinematics/biometrics journals, I was able to work GURPS ST for your average kid at various ages as well as how far they throw. Even assuming slightly better ST and skill levels for top-performing kids the data still worked out. All that gave me very good data for ST 7-10. (If I really wanted to, I could write house rules for GURPS Little League Baseball, but I imagine that it would be about as popular as GURPS Reynolds Numbers.)

From there, it was easy to extrapolate upwards for maximum human performance based on KE required to loft a baseball at a given velocity. (FWIW, for relatively untrained and young lifters, BLx6 isn't a bad measure of how much you can bench press.)

Realistic critters of ST 6 and below will have Size -3 or smaller and weights of 30 lbs. or less. They can only lift and throw very light objects so air resistance is a big factor at this level. That makes sense. Not a whole lot of small animals use projectile attacks as defenses. Those that do use very short-ranged attacks delivering small masses of toxic or caustic material (e.g., just 2-3 m range in the case of a spitting cobra).

For example, a ST 1 flower fairy is only going be be able to chuck 0.6 lbs. max. and only get maximum range from an object with a mass of 0.0017 lbs (~0.8 g). Basic Throw range is just 0.1 yards. So, they might be able to fling a tiny handful of fairy dust but not lethal elf darts.

If you want fantasy or comic-book pixies capable of hurling darts at normal combat ranges, give them limited version of Lifting or Striking ST which just apply to BL to determine Throwing speeds and distances. Alternately, treat any object with a mass of less than 1/3 of a pound (approximately 150 g/5-5.5 oz = baseball or cricket ball) as it had the same air resistance.

[kirbwarrior]

Originally Posted by Pursuivant

8) These rules add an extra calculation to already complex rules

This is probably my biggest issue with this, looking it over more carefully. I'm not entirely certain how to use the rules as they are written up and despite the continuation of the above sentence it looks even harder to use in play.

[Pursuivant]

Originally Posted by kirbwarrior

This is probably my biggest issue with this, looking it over more carefully. I'm not entirely certain how to use the rules as they are written up and despite the continuation of the above sentence it looks even harder to use in play.

In play, the only real fix is for the GM to have pre-generated range and damage tables, especially if you're working with a range of different ST and thrown object weights.

The same could be said for collisions and falling damage as well.

For characters in the 8-12 ST range the rules are easy: assume that a 1/3 to 1 lb. missile will travel 1/2 of BL in yards. At that level, collision damage is approximately the same as Basic Thrust damage, with perhaps -1 for missiles of less than 1 lb.

For longer throws, you get BL x 2 yards for in a Committed Attack and BL x 3 yards for All-Out Attack.

[kirbwarrior]

Originally Posted by Pursuivant

In play, the only real fix is for the GM to have pre-generated range and damage tables, especially if you're working with a range of different ST and thrown object weights.

Just having those tables in a clear and concise manner would be what I would want.

I personally think that Basic Throw being based on BL is super cool. Considering that distance is then based on what you can carry and damage is based on Striking ST, I think the calculations still make sense.