[RQ-Rules] Unifying Knockback and Falling Damage

[Thomas M. Cantine]

>When a giant smahes you into the ground - The Spike - then leg damage is
>probably fair. We had two Great Trolls fighting and knocking each other
>through walls, once. The knockback didn't kill them but it knocked the house
>down.
>
>Simon

I think the problem with knockback as it's written in RQ3 is that it is
completely out of touch with the falling damage. You take way more damage
being shoved three meters into a tree than you would falling three meters
straight down onto solid rock. I have therefore written up the following,
my own treatment of knockback and falling damage:


Falling

The damage for falling can be left as it is in RQ3 (i.e. 1d6 per 3 m of
height). I agree that armour should not substantially affect falling
damage, which is primarily due to rapid deceleration on impact. However, a
tiny amount of incidental damage is from contact with the surface of the
ground itself, and armour should help against that, hard armour being
slightly more effective. Thus, for falling damage, allow soft armour (of
any type) to count for 1 armour point, and hard armour (of any type) as 2
armour points. This won't make much difference when someone falls off a 30
m cliff, but will save someone tripping over a cobblestone from a few
scratches and bruises.

The better protection from falling damage should be provided by the Jump
skill, but one critical detail seems to have been omitted from the RQ3
rules: the benefit of landing on your feet instead of your head. Since all
falling damage goes to total hit points anyway, a successful Jump roll will
have no effect on one's likelihood of surviving a fall whatsoever.
Solution: allow legs to have 3 armour points each for the purposes of
falling damage, and arms to have 2 armour points, not cumulative with the
worn armour protection mentioned above. On a failed Jump, a lucky faller
might still land on an arm or leg and enjoy the benefit of this protection,
but on a fumbled Jump limbs have no armour points for falling damage. A
special success allows the faller to spread the impact over two chosen
locations, and on a critical success the faller may distribute the impact
over any number of chosen locations.

Note: The basic principles for falling damage also apply to adventurers
colliding with surfaces at any angle, such as when one sprints into a brick
wall. The damage given in RQ3 for knockback into solid objects (1D6 for
every meter of movement) is way out of line with falling damage. In
general, a movement rate of 5 m per strike rank is equivalent to a fall
from 3 m of height. Unfortunately, while kinetic energy increases linearly
with height, it does not do so for speed.  I offer therefore the following
simplified scale of impact damage for typical speeds:

        Damage  Equivalent speed        Typical situation
        1D3             1-2 m/SR                Walking into wall; tripping
over cat
        1D4             3-4 m/SR                Running into wall; falling
from 1 m
        1D6             5-6 m/SR                Sprinting into wall;
falling from 2-3 m.
        2D6             7-8 m/SR                Trotting horse.
        3D6             9-10 m/SR               Charging horse

        While it may not be necessary to calculate beyond this speed, it's
interesting to note that kinetic energy increases as the square of
velocity. This means that an unhappy adventurer travelling at 60 m/SR
should suffer approximately 100D6 damage on impact, demonstrating why
trebuchets are not a viable means of personal transportation. In any case,
since the same amount of kinetic energy is applied to the adventurer on
launch (though over several meters of acceleration) for maybe 50D6, it
doesn't matter how one lands; the launch will kill you.
        One might wonder how it is that a person being hit with a boulder
flung by a trebuchet would take only 12D6 damage, but 100D6 damage from a
wall at the same relative speed of impact. While dead is dead, the
ballistic adventurer will leave fewer recognizable bits behind, because
every one of those bits will make the same abrupt splattering deceleration.
In contrast, the trebuchet ball might carry away with it a couple of hit
locations, leaving behind several relatively intact portions. Indeed, an
adventurer struck in the arm by a trebuchet might well survive, since no
more than twice a limb's hit points may be done to total hit points through
ordinary damage. No such luck with falling damage.

Knockback

When does knockback happen?
There are four basic types of situations in RQ which call for knockback.
        (1)   Someone receives a hit which, before armour, does more damage
than the character's SIZ characteristic. I modify this from basic RQ3 by
saying that this only applies to blunt weapons, since a major part of the
damage taken from a slashing or impaling weapon has nothing to do with a
transfer of momentum. (The damage STOPPED by armour should definitely
contribute to knockback, but it's much simpler just to say only blunt
weapons do knockback this way.)
        (2)  Special success with a blunt or slashing weapon. I have
omitted slashing weapons from this, for reasons discussed above.
        (3)  A moving adventurer or monster collides with another. This can
happen when one adventurer is knocked back into another, or when one runs
(deliberately or blindly) into another. To determine if knockback takes
place, match the mover's SIZ + current movement rate (in meters per strike
rank) against the stationary adventurer's SIZ on the resistance table. If
the stationary adventurer is aware of the impending collision, he may
include his DEX with his SIZ on the resistance roll, or he might already be
bracing against knockback with STR instead (as per RQ3). If the moving
adventurer is moving under her own power (rather than simply having been
knocked back herself), and actually intends to collide, she may also add
her DEX for the resistance roll. On a success, knockback occurs; see below
for magnitude and effects. On a failed resistance roll, the moving
character suffers knockback of 0 meters; see below for effects. (The
stationary character could alternatively Set Spear vs. Charge, precluding
the use of DEX in the resistance roll if the spear attack misses. If it
hits, though, it preempts the knockback attempt...)
        (4)  An adventurer or monster deliberately pushes, shoves, trips or
otherwise attempts to knockback (or knockdown) someone. This is similar to
RQ3's old intentional knockback rules, with the resistance roll of
(SIZ+STR) vs (SIZ+DEX), but requires the establishment of a connection for
the transmission of force in the first place. This is done with a
successful attack roll, and the weapons usable for this are Fist, Kick (for
swashbucklers especially), Grapple, Shield Attack, or any hafted weapon
used with both hands (the classic quarterstaff shove). A successful attack
does no damage, but if it is neither parried nor dodged, it allows the
attacker to attempt the same old resistance roll as per RQ3. This takes
place on the same strike rank as the attack.

How much knockback?
        The amount of knockback is easy to calculate: it's usually just the
attacker's rolled damage bonus in meters, minus the target's rolled damage
bonus, plus the attacker's current movement rate in meters per strike rank.
When a character is knocked back, you may treat that character's movement
rate at any point as the number of meters remaining in the knockback. Thus,
if Throg is knocked back 5 meters by Lulu, and he bumps into Grothnar 2
meters away, his movement rate on impact with Grothnar for damage and
knockback purposes is 3.

What is the effect of knockback?
        First, and most obviously, the target is displaced a certain number
of meters. Second, if knocked into a solid object with sufficient force,
the target may suffer damage from that impact. Third, the target may fall
to the ground.
        The damage suffered from impact with a wall or other solid object
is calculated as in falling damage according to the movement rate of the
knocked back adventurer. Impact with an object that can itself be knocked
back (like another adventurer) does half this amount, rounded down.
        To avoid falling down when knocked back, a DEX x 5 roll is
required. Another DEX roll is needed to avoid falling down on every
subsequent impact, so in the above example, Throg would need to roll once
when knocked back by Lulu and then again when bumping into Grothnar.


/=================================\
|       Thomas M. Cantine         |
|     "Will Think For Food"       |
\=================================/
http://www.incentre.net/tcantine