Subject: Gore and Gash, Volume 3, Number 6
First distribution: April 1, 1989
This issue:
Searching Rules (Burton Choinski)
Ed's note: Trollpak is out! Note that it still isn't the complete version of
the old Trollpak, since they will have *separate* products Troll Realms
(already available), Troll Gods, and The Sazdorf Clan, all of which are
heavily based on things that were part of the original Trollpak. There will
be a review when I get the time.
Several of you may have missed the last few issues due to mailer problems.
Please let me know what you've missed.
---
Subject: Searching Rules
From: choinski@env.prime.com (Burton Choinski)
The following pages detail the hexagonic searching system, a system I have
developed to make searching in any game system easy and somewhat realistic.
1 General Premise
The basis is this system was developed for Powers & Perils, which uses a hex
system of movement. It can be applied equally well to many other game systems.
There are three basic parameters to consider when using any searching metheod:
Search Area, Visual Area and Travel Speed.
_Search Area_ is the area to be searched for the object. This could range from
tens of feet (looking for a hidden person) to tens of miles (combing the
countryside for a lost temple).
_Visual Area_ is a value determined by the referee based on three variables:
Size, Line of Sight, and Cover. In general, the larger the object, the larger
the radius in which you can see it (compare looking for a man to looking for a
house in the same environment). Second, if there are lots of breaks in your
view (hills, large trees, lost of brush) the visual area will go down a lot.
In areas of little cover (flat, featureless plains) the visual area will go way
up. Finally, if the object in question is bright orange in a green forest it
is visible at a greater distance then if it was green and covered in vines,
leaves, etc. The referee must decide for him/herself at what range a character
or NPC could reasonably see the object or person being searched for given all
the above conditions. Other senses should be used if they have a better range.
(thus, if a hunting Broo can see you within 10m, but can smell you within 50m,
use the smelling range.)
_Travel Speed_ is the speed of travel in the search. The idea behind this is
the fact that faster searchers can search an area more rapidly, thus searching
more area per time period, thus giving a higher chance of finding the object in
question in the time period.
There are two ways of using this system: Time based and probability based.
2 Time Dictated
A search dictated by time means "for a given time period, what is the
probability of finding the searched object?" The variables are:
- a, the radius of the search area in units.
- v, the radius of the visual area in units.
- t, the total time of search.
- h, the size of a "unit". This is based on the game system and the
situation. For RuneQuest this is most likely 3m distances for combat
or short distance situations, 10-100m for longer periods of time.
- s, the speed of the searcher. This should be based on the units per
standard time (For RuneQuest, units/SR or units/minute)
Using these five values, the formula below will return the base chance of being
in a position to find the object being searched for. This assumes the target
is stationary and the searchers are being careful to comb the entire area. If
the searchers are sloppy or not very careful, divide the base chance by three.
If the target is moving, the base chance may be reduced by one-half.
-------------------------------------------------------------------------------
| |
| 50st(v+1)/ah(a+1) |
| |
-------------------------------------------------------------------------------
As an example: Sheven is on the run from a large and very angry Dark Troll.
Luck was on his side when the Troll was temporarily blinded by the thrown sand,
but the Monster is on his tail again, out for blood. Sheven runs over the hill
into a large patch of forest surrounded by grassland. Deciding to trust his
abilities to keep hidden in the woods, he heads for the brush and hides in it's
interior just as the very pissed Troll comes over the top.
Thorg of the Broken Spire, looking for the little man who dared to steal from
him, spots the island of woods and pauses. He sees no movement in the tall
grasses, so he assumes the little wart of a human must be in the woods.
Keeping his maul ready, he strides into the woods to find him.
Let us say that each unit is 1m (h=1). The forest-island is about 500m across
(a=250) and Thorg moves at a rate of 4m/SR (s=4). Given the high amount of
cover, let's say Thorg has to be within 10m of Sheven to have a chance of
spotting him (v=10). Finally, Thorg is tiring of this game and quite
frustrated at him getting away, so he will not be quite as careful. We will
assume 1 turn per roll (t=10 SR). Sheven will not try to move. Totalling it
up, poor Sheven has (50x4x10x(10+1))/(250x1x(250+1)) or a base 35% chance of
Thorg being in a position to see him each turn. Because we said Thorg is not
being careful, this is divided by three to 11% each turn.
Each turn the referee rolls 11% or less, and Sheven sees Thorg stomping around
his hiding place, a hide vs. spotting roll is made. If Thorg fails to find
him, he could still have another chance at reduced chances (see below) The
referee could (and should) really play this up ("Thorg is almost breathing down
your neck! Do you sit still and pray, or bolt?").
What happens after finding the area? If the searcher is being careful, it
means he is trying not to search covered area again. Divide the finding chance
by TEN. If he is being careless, divide it by TWO. If he is being VERY
careless (just stomping around), divide it by THREE.
Increasing the number of searchers will multiply the success probability. In
this case, unsuccess full finds reduce the chance by TWO if careful and not at
all if careless. Sometimes it takes an army just to search a good sized area
in a given period of time.
3 Probability Dictated
A search dictated by probability means "For a given probability, how long will
each search period be?" The variables are:
- a, the radius of the search area in units.
- v, the radius of the visual area in units.
- n, the probability of success, from 1% to 100%.
- h, the size of a "unit". This is based on the game system and the
situation. For RuneQuest this is most likely 3m distances for combat
or short distance situations, 10-100m for longer periods of time.
- s, the speed of the searcher. This should be based on the units per
standard time (For RuneQuest, units/SR or units/minute)
Using these five values, the formula below will return the time required for
each searching period. This assumes the target is stationary and the searchers
are being careful to comb the entire area. If the searchers are sloppy or not
very careful, multiply the time by three. If the target is moving, the time is
DOUBLED.
Using these five values, the formula below will return the time required for
each searching session.
-------------------------------------------------------------------------------
| |
| ahn(a+1)/50s(v+1) |
| |
-------------------------------------------------------------------------------
As an example: Sheven and company are looking for Thorg's hidden home. They
know the rough area, but not the exact location. After studying Thorg's habits
(from a distance) and from Sheven's information, they have narrowed the search
area to an area 2km across (a=2000). They are searching a rugged area, so the
referee decides that they travel only 1km/hour (s=1000). Units are obviously
in meters (h=1). However, the terrain is very rough and his cave is very well
hidden, so the visual distance will be quite low. If they have 5 party
members, they could either split up and search seperately (possibly a bad move;
Sheven advises against having a one-on-one with Thorg) or search as a spread
out group. They decide on the later. A person must be within 50m to see his
cave, but they are combining to form, in effect, one "entity" with an extended
searching range. They decide to be no more then 60m apart (30m to the center),
so the visual range is now 80m (v=80). Finally, the referee decides to give a
base chance of 25% (=25). Putting it all together, the time per search roll is
(2000x1x25x(2000+1))/(50x1000x(80+1)) or 24.7 hours. At a rate of 8 hours per
day for searching, this is 3 days per search roll.
Had they split up (the cowards!) they would have had a collective time of of
(2000x1x25x(2000+1))/(50x1000x(50+1))/5 or 7.8 hours (1 day) for each search
roll. The first roll is always given at 1/2 the listed time; all subsuquent
rolls are made after the full time period.
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