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Infravision
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Infravision & Your Fantasy Hero by
Roger E. Moore
What would it be like to
see in the dark? My interest
in this topic was sparked years ago when I tried to figure out just what my
half-orc AD&D(R) game characters could see using infravision in a dungeon. I
wanted every advantage there was for those obnoxious little guys. Additionally,
I wanted to know just how well infravision-using monsters could see in the dark,
because I wanted my characters to avoid being seen and promptly eaten, as a
number of them were. This
interest was sparked again recently by an article in a science magazine on
infrared vision. Some very intriguing points came to light, and the results are
offered here in the hopes that AD&D and D&D(R) game players everywhere
will find them useful. (Certainly, my half-orcs would have gotten a longer leash
on life with this information.) How
infravision "works" We should really start with a look at real-world infrared light and
infravision. This makes certain game aspects of this sensory power clearer, and
also highlights inaccurate, contradictory, and problematic aspects of
infravision in game play (which will be discussed in depth later).
The
science article that fired me up for this topic was "Seeing the World
Through Infrared Eyes," by Neil F. Comins (Astronomy Magazine, June 1991,
pages 50-55). This excellent piece covers the basics of how infravision would
work in realistic terms. It's worth hunting for this article in your local
library and copying it for reference. That and a few encyclopedic entries are
the basis for the information that follows. Infrared
radiation is normally invisible, lying just below red on the electromagnetic
spectrum. It is given off by hot objects; the hotter the object, the more
infrared light it gives off. Very hot objects eventually give off visible
light--red light at first, then orange, yellow, and white as the heat increases.
We can sense heat radiation on our skin, the largest sensory organ we have, but
we cannot detect more than a general direction of the heat source and an idea of
how hot the source must be. Certain
snakes called pit vipers are able to detect infrared light more accurately than
we can, though only within a short range. Several sense organs called pit organs
lie to either side of a pit viper's head, between the eye and nostril. Changes
in heat radiation as little as 1 degree can be detected. The snake senses the
direction of the heat source by moving its head back and forth, noting the
direction and intensity of the heat it senses. We've
known about heat for eons, but infrared light itself was discovered by an
English astronomer, Sir William Herschel, in 1800. A very practical use for
infrared light was found during World War II, when electric sniper scopes were
invented. Sniper scopes were attached to rifles and gathered distant infrared
light coming from the bodies of soldiers, converting it to visible light for the
sharpshooter. This allowed sharpshooters to fire on enemy positions at night.
(As will become apparent, some versions of infravision in the AD&D game were
based on sniper scope characteristics.) Infrared
light has less energy than visible light, but it behaves in much the same way.
Some infrared radiation is absorbed by molecules in the air. However,
near-infrared light, which is the part of the infrared spectrum closest to
visible red light, is reflected by most objects and thus can be used to detect
them. We see a chair by the light reflected from it; a pit viper can detect
nearby objects by the near-infrared heat reflected or emitted from them. Our
ability to actually see infrared heat in detail is blocked by several major
problems. Because infrared light is less energetic than visible light, a human
able to see near-infrared light clearly would need eyes about 5-10 times larger
than normal. Worse, heat is emitted from many objects all around us; stoves,
furnaces, living beings, light bulbs, hot car engines, and sun-warmed rocks,
concrete, bricks, and asphalt for example. Almost everything with any warmth
would glow as if it were a light bulb, though with an intensity proportionate to
how hot it was. Thus, an oven will be "brighter" than a warm rock. What
this means, of course, is that anyone able to see infrared light also will see
his own body warmth. We have body temperatures just below 100 degrees F., which
is enough to blind us with heat radiation. It's like trying to take a picture
when the camera itself emits light inside and out, ruining the film. To
prevent such heat blindness, an infravision-using creature would need some sort
of insulation around its eyeballs to keep the body's heat out of them, and some
kind of refrigerant to keep the eyeballs cool so they become sensitive to
outside light. This insulation and refrigeration would be done biologically.
(Don't ask me exactly how, but I'm sure Mother Nature would figure out a way.)
However, let's face it: We're dealing with magic, not science, and magic can do
anything. Our problems are solved at a stroke, even if it doesn't please the
scientists among us. Another
option--useful for beholders, giant snails, and crabs--is to put the eyeballs on
stalks, separating them from the rest of the body. The eyes are thus air cooled,
so no other refrigerant is needed. I don't think beholders and so forth have
infravision, though (as is noted later) if they've lived underground for a long
time, they've probably developed it. In
some ways, the way that infravision is described in the AD&D game rules
implies that it works in the same way that our night vision normally works.
Rod-shaped cells in the retina of your eyes can detect very dim light after a
short period of adjustment to darkness, which you should be familiar with each
time you go into a dark room. At first you can't see a thing, but over a period
of minutes you start to see more and more objects in what little light there is.
Eventually, faint light sources like the full moon, digital clocks, and even
pure starlight can seem quite bright, even painfully so. However, because rod
cells are not color-sensitive like the eye's cone cells, night vision is mostly
black-and-white vision; maybe "shades of gray" vision is more
accurate. (Infravision was described as being like black-and-white vision in the
original AD&D game, too, as noted later.) Night
vision can be instantly spoiled by bright normal light, which is why driving
experts tell you to look away from oncoming cars at night, to preserve your
eyes' sensitivity. Infravision in the AD&D game is spoiled by bright visible
light, extremely hot objects like fires, and magical light. Perhaps fantasy
creatures with infravision have magical cells in their eyes that work like rods,
but pick up heat instead of faint visible light. Who knows? So much for
how infravision works. What can you see with it? The infravisual world: Aboveground We'll assume that your campaign world resembles our
own Earth in that it has a normal day-night cycle with a sun like our own. (If
this is not the case, you can make adjustments as we go along.) What would your
heat/infrared picture of the world look like, then? Let's use some logic as we
look around.
In
the daytime in summer, everything bathed in sunlight is warm. Things that retain
heat well, like large rocks, will be warmer and stay warmer longer than things
that lose heat rapidly in cool winds, like thin leaves or blades of grass. The
greatest normal heat source is the sun, which we can easily assume is too bright
to look at with any form of infravision. Sunlight in fact ruins AD&D game
infravision, so we would rely on normal vision alone. Air is assumed to be
invisible, whatever its temperature, unless it is extremely hot (see below). So
infravision is useless in broad daylight. Once darkness falls, however, the
landscape is still hot. Objects retain heat from the sun and radiate it slowly
away, which keeps the night side of the world from freezing. (Even magical
worlds need thermodynamic physics!) With the sun gone, a creature with very good
infravision could see almost normally right after full darkness falls, since the
terrain will radiate light. We can assume that a combination of rod-based night
vision and magic-based infravision would be a potent mix, allowing vision about
equal to normal sight in full daylight. Distant images would be fuzzier and less
distinct than usual, so a far-away orc might look like an ogre or a halfling,
but it beats seeing nothing at all. Different
parts of the landscape will cool off at different rates, so things will look
strange. Rocks would be "brighter" than trees, for instance. Water is
generally cooler than land, but water also retains heat better than land; thus
lakes and seas might seem "brighter" than the shoreline, especially
late at night. Very hot air, such as that escaping from chimneys or fires, will
glow faintly like a luminescent cloud. Other
warm things in the world include live animals, especially the warm-blooded ones,
and fire. A deer, a human, and a chipmunk all radiate heat--more heat when they
are ill or physically exerting themselves, less heat when standing still or
asleep. Certain magical animals, such as salamanders and red dragons, can be
assumed to produce much more heat than other creatures their size. I recall
reading that drinking alcohol causes the body to radiate more heat than usual,
so a drunkard could be detected by being "brighter" than other people. Objects
in close contact with living beings, like clothing, weapons, tools, chairs, and
beds, will radiate some heat after the beings leave or discard them. In time, of
course, those objects will completely cool off. Standing on a spot or leaning
against a wall for a while also will leave residual heat behind, which could be
noticed. Scuffing or shuffling feet would leave infrared "footprints"
that could be tracked, though not for long. Friction from dragged objects, like
heavy sacks or combat victims, also could be detected, as could places where
surfaces have been rubbed together for long periods of time (machine gears,
gristmill stones, axle joints, spinning wheels, etc.). Physical blows, like
being smacked with an open hand or a blacksmith's hammer, also raise the
temperature of solid surfaces for short periods of time. Fires
produce vastly more heat than living beings. Seeing a living being hiding next
to a blast furnace in a dark room would be almost impossible, like seeing a
firefly's light next to the sun's. Manmade and natural sources of fire include
matches, pipes, cigars, candles, torches, campfires, bonfires, hearths,
furnaces, forest fires, lava, and embers. All flame sources are assumed to emit
enough infrared and visible light to ruin infravision near them. Note however,
that a "dead" fire would radiate heat long after the last ember has
vanished, and likely would be detectable at a great distance. A forest fire
would "light up" the landscape for many hours after the flames are
gone. Remember,
too, that infravision also detects the lack of heat, just as normal vision
detects the lack of light. Snow and ice will look very dark in infravision if
seen without visual light from moons or stars. A cold-producing object like a
refrigerator also will look darker than objects around it. Cold-producing
creatures like brown mold or a lich (whose frosty touch causes frostbite damage)
will look very "black." It's
worth a word on what sorts of creatures could not be seen with infravision.
Creatures that are normally able to turn invisible, like pixies, should also be
invisible to infravision but not to other senses like smell. Any creature that
is roughly the same temperature as its surroundings, like a cold-blooded insect,
fish, amphibian, or reptile, would be harder to see at night, though even
cold-blooded creatures aren't always exactly the same temperature as the
environment around them. (Live things move and so generate friction from moving,
for one thing.) Magical beings that radiate no heat at all, like undead
skeletons and zombies, would be almost invisible to infravision unless revealed
by reflected infrared light or else blocking a much hotter source, revealing
their outline. With
so many heat sources at night, and so many things that will reflect infrared
light, there will be a multitude of infrared-light shadows. The landscape will
lack clarity and seem a bit out of focus (even more so at greater distances), as
well as painted in shades of gray. It's a confusing, alien world, but any
creature born with infravision would be quite accustomed to it and might
instantly recognize any critical feature it sees. Neil
Comins' article notes that the night sky itself would change when seen through
infravision, but modern-world astronomy is considerably different from the
AD&D game's SPELLJAMMER(R) setting "physics." In essence, any heat
source in wildspace will glow fuzzily in infravision, but it's up to the Dungeon
Master to choose which things seen in the night sky are heat-emitters and which
are not. Stars,
for instance, might radiate only visible light and no heat at all, thus being
invisible in infravision but not to normal or night vision. Fire bodies, like
suns, will certainly emit enormous amounts of heat and be easily visible from a
planet's surface as enormous, brilliant, fuzzy balls in the sky. Air bodies will
emit or reflect very little heat (becoming invisible), and earth and water
bodies will only reflect heat (being barely visible unless they are close to a
heat source). Let's
take three well-known crystal spheres and see what's to be seen in the
infravisual sky. Oerth, home of the GREYHAWK(R) campaign, is set in Greyspace
(described in the SPELLJAMMER accessory SJR6 Greyspace). The local sun, Liga, is
an enormous fire body that will temporarily blind any infravision-using creature
dumb enough to look directly at it. Oerth's two moons--Luna (a.k.a. Raenei) and
Celene (a.k.a. Kule)--shine clearly by reflected infrared light from Liga,
passing through normal lunar phases. Other planets are much farther away and
thus much fainter, though some have their own heat source, like the air world,
Edill (which has small fire bodies within it). Stars in Greyspace are actually
gigantic gemstones set in the crystal sphere itself that emit light but no heat,
thus being invisible to infravision. Krynnspace,
home of the DRAGONLANCE(R) setting, has two fire bodies: the sun and Sirion, the
small innermost planet. The sun, of course, is staggering bright (just like Liga,
above, or our own Sun). Infravision makes Sirion look like the second-brightest
body in the sky, however, as it gives off so much more heat than any other
planet. Reorx, an earth body that is the second planet out from the sun, is
third brightest; it reflects heat from both the sun and Sirion, which often
appear widely separated when seen from Krynn. Krynn's three moons also reflect
heat from both sources, becoming the fourth, fifth, and sixth brightest bodies.
Outer planets reflect less light and are thus dimmer in Krynn
"infra-sky." The stars here, as in Greyspace, are invisible to
infravision, emitting only light from the quasi-elemental plane of Radiance. DMs
should read SJR7 Krynnspace for more. Finally,
from the justly famed surface of Toril (home of the FORGOTTEN REALMS(R), Kara-Tur,
Horde, Maztica, AL-QADIM(R), and MALATRA(TM) settings), the sun is the dominant
object in the "infra-sky." It is interesting to note that Coliar, the
second planet out from the sun, is almost invisible because it is an air body;
the sun's heat goes right through it. However, because of the small
"islands" of rock circling within Coliar, infravision might show the
planet to actually be a spherical collection of pinpoints of light, reflecting
heat from the sun. Selune (Toril's great moon) and the Tears of Selune (a
cluster of asteroidal bodies circling Selune's trailing Lagrange point) shine
clearly by reflected heat from the sun, when seen from Toril. Other worlds
appear very faint, with the exception of Anadia, an earth body and the closest
world to the sun, and Garden, which is illuminated by one of its moons, Sunson,
a miniature fire body. Garden's other moons might also show up clearly in
infravision through a telescope, reflecting Sunson's heat and light. Again, the
stars are infra-invisible. See SJR2 Realmspace for more. Given the above
settings, you can see that even when the sun goes down at night, infravision
might still reveal a great deal about the surface world if a heat source is
still in the sky. Garden's Sunson might be bright enough infravisually to cast
shadows at night on Toril, like a full Moon on our Earth. This would be
especially true when Garden is in conjunction with Toril (i.e., when it is
closest to Toril). Sirion would appear from Krynn to be an extremely bright
"morning star" or "evening star" (in the manner of Mercury
or Venus, as seen from Earth), but it would also reveal the local landscape
quite clearly. Collisions between celestial bodies will produce brief bursts of
infrared light (heat). As asteroids in the Grinder of Greyspace or earth bodies
within Krynnspace's air-body Zivilyn collide, an infravision user elsewhere in
local wildspace would see a brief burst of bright light that fades away rapidly.
If a DM is designing an original campaign world using a completely different
astronomical set-up, he can use logic and the above examples in designing the
"infra-sky" of his world. What about an air body full of nonluminous
but very hot gases? A cold air world that eclipses the sun, not reducing visible
light but cutting down heat radiation briefly? You might also consider creating
a large selection of infravision-using monsters on your world, with behavioral
patterns that vary according to the heat-brightness of the sky. Carnivores,
especially, will be more active when they can see clearly. The infravisual world: UndergroundInfravision
is remarkable enough to surface-dwelling creatures. Let's look at what it's like
for subterranean beings, and what advantages and disadvantages they gain from
it. In
our real world, deep caverns tend to have a uniformly cool temperature; Mammoth
Cave, in central Kentucky, has an average temperature of 54 degrees F. that
varies only slightly year-round. This coolness makes everything look the same,
bland shade of gray to an infravision user, but there is plenty of hope here for
diversity. For one thing, large openings radiate only faint heat (from objects
beyond them), so such openings will look dark. More distant objects radiate less
visible heat than closer ones, so distant objects are dimmer and darker. You
could thus pick out the shape and direction of an unused tunnel with little
trouble. Running
water underground is often extremely cold, so cave water will seem very black,
as will the rocks surrounding it. If a cavern complex is near a geothermal heat
source, like a geyser or (heavens forbid) volcanic magma, the entire cavern will
grow warmer and "brighter" as an infravision-user gets closer to the
heat source. Caves
often have a variety of life in them, especially in fantasy worlds, and living
beings will radiate enough heat to "infra-illuminate" their
surroundings. The more beings, the brighter their living space; a thousand
goblins should be able to see their underground lair quite clearly with no other
"light" than the heat from their own crowded bodies. Heat-producing
magical creatures, like red dragons, will of course radiate vast amounts of
infrared light. A red dragon would have an advantage, too, in that one short
puff of flame will ruin the infravision of any approaching creature, with fatal
results for the blinded ambushers. Some cold-blooded creatures like slithering
trackers would be invisible to infravision, again with fatal results for cocky
adventurers. The special dangers of skeletons, clay golems, and other
"heatless" monsters becomes highly apparent. Some
undead, however, radiate cold. Liches, for instance, cause damage from their
chilly touch; they and their hands should "glow black" in infravision,
standing out against warmer backgrounds, even cave walls. Read the descriptions
of monsters carefully if you want to produce a more detailed and intriguing
picture of underworld life to adventuring dwarves, gnomes, and elves. Speaking
of fantasy races, a short history of infravision, as it appears in TSR's fantasy
games, is in order. Infravision and the AD&D gameReferences
to infravision are scattered throughout the AD&D and D&D game rules, but
it becomes obvious that the concept underwent much expansion and refinement over
the years since either game first appeared. It would help to start out with a
look at what infravision used to do in fantasy games, and what it does now--as
well as collect the rules on infravision together in one spot for ease of
reference. A few areas of omission and contradictions that have confused the
playing of infravision will become apparent. Certain
races in the Chainmail rules (the war-gaming rules from which role-playing
sprang) were able to "see well in dimness or dark." Dwarves, gnomes,
goblins, kobolds, and orcs, as subterranean races, needed the ability to get
around in caves and mines when candles and oil lanterns weren't available. If
you dumped the infravision concept entirely, this sort of vision could be either
light-intensifying vision, making the most of every visible-light photon in the
area, or a form of magical radar, allowing for an accurate map of local
surroundings without recognition of color or "flat" things like
paintings, handwriting, etc. It could even be magical vision that makes dark
areas seem to be lit by sourceless light, so there are no shadows (color is
optional). Take your pick. Hard
on the Chainmail game's heels in 1974 came the D&D Original Set, those three
tan booklets in the white box. There, the infravision spell first appeared. The
original version of the spell allowed the user to "see infra-red light
waves, thus enabling him to see in total darkness." (Of course, you still
might not see in total darkness if there were no heat sources around.) The spell
lasted for one day and had a range of 40-60 feet. Interestingly, it wasn't until
a later D&D supplement appeared (the Greyhawk book) that dwarves, gnomes,
and elves were noted as having infravision allowing them to see monsters up to
60 feet away in the dark. (Elves were probably allowed this so they could see at
night, though light-intensifying vision would have been more logical.) The
original AD&D game's Player's Handbook and assorted monster descriptions
gave infravision to many creatures, including every demihuman PC race except
certain halflings. Different types of infravision began to appear, too, defined
by range. Poor infravision was effective only out to 30 feet, and was found in
certain halflings and derro, an evil dwarflike race. Normal or standard
infravision, good out to 60 feet, was the most common variety. Superior
infravision extended out to 90 feet, as was the case with trolls and
troglodytes, or 120 feet, for drow and duergar (evil dwarves). In one place
(page 102), the Player's Handbook says that monsters living in dungeons have
infravision out to 120 feet; why then do some have shorter ranges? Hmmm. Superior
infravision, however, involved more than simply receiving heat radiation.
Creatures with long-distance infravision were noted in the 1st Edition DUNGEON
MASTER(R) Guide (page 59) as emitting infrared light from their eyes (magically,
of course), then seeing the reflected radiation. (This would not be possible in
normal science, as noted earlier, but this is a magical universe we're talking
about.) The eyes of any creature with infravision out to 90 feet or more are
noted as glowing red quite brightly when seen by any other creature with
standard infravision. Most monsters in underground areas were said to have
superior infravision. This
brings up a curious point: How far away can an adventurer with standard
infravision detect one with superior infravision? Can the adventurer see danger
coming before the dangerous creature sees him? Well, if you get picky about it,
you can say that the standard range of 60 feet is fixed; you can't see farther
than that, no matter what heat source is out there. On the other hand, it is
clear that the original intent of the rules was to have the 60 feet range be
that at which the body-heat radiation from monsters (and normal people) could be
seen. The implication is that stronger sources of infrared light could be seen
if they were farther away. A
liberal DM should note that a creature with 90 feet or 120 feet infravision is
actually emitting infrared beams out to 180 feet or 240 feet, respectively. All
infrared light going out from its eyes must be reflected back to its eyes to be
seen, so in theory those eye beams should be detectable by infravision out to
those doubled ranges (assuming those eye beams don't first encounter a surface
that causes them to be reflected). Furthermore, near-infrared light reflects
from most normal surfaces just like normal light. A monster with superior
infravision "paints" everything it sees with powerful heat rays, just
as if it were carrying a double-beam flashlight. (Perhaps dwarves and gnomes
have appropriate expressions like, "That troll was so close that its eyes
could've burned the skin off my arm!") Thus,
a gnome wandering an abandoned mine tunnel might see the corridor ahead of her
"light up" with faint infrared light if there was a duergar 240 feet
ahead of her. The duergar has the advantage in having a much broader range of
accurate vision, but the gnome has the advantage of early detection. The gnome
can immediately flee or hide, unseen by the approaching duergar. This
argument is buttressed (and contradicted) by the note in the original DMG (page
59) that, outdoors, infravision allows for detection of warm or cold figures at
a range of 100-300 feet. Vision is said to otherwise be equal to "a bright,
starry night, with full moonlight." Cannot the duergar then see the gnome
at 240 feet? What heat sources are present that allow for this greater range of
vision? And if you can see up to 300 feet outdoors, why can't you see that far
indoors? Game logic breaks down at this point. To
the rescue, perhaps, comes the earlier notes about a sun-warmed landscape and
rod-based night vision. As a rule of thumb, let's say that a creature with
infravision can see three times as far outdoors at night as it can in a deep
cavern, because the landscape is warmer and radiates more infrared light. A
halfling with poor infravision thus can see most outdoor objects out to 90 feet,
and a duergar (with infrared eye beams) can see out to 360 feet. The gnome in
the earlier example should obviously avoid meeting duergar at night in open
fields; the duergar will see the gnome first. In
the original PHB (page 102), things seen with infravision are described as
appearing in a colorless way to an observer. Warm things look bright, as if they
were emitting light. Cooler things look progressively more gray, and cold things
appear black. This fits with the black-and-white view of infravision developed
earlier. Recent versions of the D&D game have instead substituted certain
colors for different heat temperatures (D&D Cyclopedia, pages 24-25), and
there is that nagging PHB note about the red-glowing eyes of a creature with
superior infravision. The optional rules for infravision in the AD&D 2nd
Edition game DMG (page 119) also allow for "pseudo-color" infravision,
as typically appears in a thermogram. I'll still opt for the simpler no-color
view, which makes it just like the view you get from a sniperscope. Does
infravision work underwater? Yes, but badly. Water is a very poor conductor of
heat, despite what any game rules say. Though the original DMG allowed
infravision to work underwater to a limited extent, but it would be more
accurate to cut it off completely. Cool water will dampen out nearly all heat
radiation, and warm water will obscure it. I'm no scientist, but I'd give
infravision an underwater range of about 1 feet, no more. Very hot sources, like
a volcanic vent, will boil all the water near them and make an infravisual view
of them merely bright, fuzzy blobs that fill your field of vision. If you are
liberal, you can keep the limits set by the original or AD&D 2nd Edition
rules (i.e., normal underground ranges). Getting clever with infravisionWhat
new tricks can infravision bring to a typical AD&D game? Here are some
possibilities: Given
that infravision is not as precise and focused as normal vision, the chances for
mistaken identity increase when only infravision is used. An orc at a distance
looks like a human or a hobgoblin; long experience and closer inspection (at
great risk) will tell the difference. DMs should play up on this at every
opportunity. As
a rule of thumb, a DM could say that accurate identification of a creature can
be made using infravision only when the target being is one-third the distance
of the spotter's infravision range. Thus, a dwarf can accurately identify a
comrade at a range of 20 feet (one-third of 60 feet), and a duergar can identify
a fellow monster at a distance of 40 feet. Can
you read by reflected infrared light, if no normal light is present? For the
record, we will assume not, unless the heat source is very strong and the
writing is only inches from one's eyes. Thieves
with infravision can learn to hide themselves from other creatures with the same
power. A very powerful, blinding source of heat or the presence of many
separate, man-sized sources of heat (like a group of bodies immediately after a
battle) can conceal the thief's presence quite well. However, simply hiding
behind a rock is no help at all, as the thief's own heat radiation will be seen
around the rock's edges and "painted" over background objects.
Wrapping up in a blanket might help at first, but the blanket will slowly grow
warmer (and brighter). Hiding against a cold object will make the warmer thief
stand out as if he were in a spotlight. If you are playing a thief (as a player
or DM), imagine that character as a permanent, glowing light source. How can you
hide that light? Magical invisibility might be the only foolproof recourse--but
even that can be challenged by creatures with superb senses of hearing or smell. The
descriptions of monsters should be carefully examined to determine if any being
might radiate more or less than the "usual" amount of heat.
Considerable leeway is given for the DM here. A dragon turtle, which breathes
steam, and a remorhaz, which is incredibly hot, are likely to put out enormous
amounts of infrared light. What about a flametongue long sword or a necklace of
missiles? Though it is tempting to rule otherwise, magical items might not put
out any heat at all, no matter what their powers, unless the description of them
in the DMG says they do. Consider
the infravisual effects of certain spells. Fireball will produce a burst of
infrared light that will temporarily blind any creature totally dependent on
infravision. Incendiary cloud is easily distinguished from all other cloud-type
spells because the cloud radiates so much heat that it glows brightly in
infravision. Burning hands could briefly illuminate a large area like a flash
bulb, if the infravision users had their backs to the spell effect so they
weren't blinded by it. Dancing lights, which radiates no heat, could be
instantly told apart from real torchlight by infravision users. Chill touch
makes the user's hand seem black (cold) in infravision. Use your imagination
with a careful touch of logic and reason for other spells. Everything
that a dwarf knows about infravision is likely known by a goblin, and vice
versa. Creatures who have no infravision are more likely to fall for certain
traps set by those who can see heat. For instance, a goblin stonework trap that
was recently used or tested will be visible to a dwarf, who can detect the heat
from the friction of stones sliding across each other. An ambush site will
radiate enormous heat from the bodies of the gathered ambushers, tipping off
other experienced dark-dwellers. A tank of cold water, set over a thin, wooden
ceiling, will made the area around it very dark. A corridor recently hit by a
fireball spell will radiate much heat (and probably smell burnt as well); the
same corridor recently hit by an ice storm will seem very dark. Fresh blood and
body wastes will retain high temperatures for a short time. You get the idea.
Dwarf-kin and goblin-kin love battling the ignorant armies of surface dwellers
who enter their realms, but hate battling each other, since they already know
all the best tricks. Certain
"clean-up crew" monsters, like gelatinous cubes, take on special
significance for infravision-users. A 'cube is assumed here to radiate no heat,
and it likely blocks heat transmission as well. It might become
"visible" to a dwarf or goblin because it cuts off the normally
expected scenery down a corridor, as if the corridor ended abruptly in a cold
wall. Humans wouldn't figure it out, but a clever dark-dweller would stop,
probe, then go another direction. Newly
discarded items like clothing, armor, and weapons would reveal much to
infravision, like how long they had been abandoned (depending on how cool the
items were) and whether the items had been used--any warm blood on the blade? A
newly set underground trap, placed by a human who was unaware of his own heat
effects, would be avoided with laughable ease by a hobgoblin or gnome. A
few new magical spells suggest themselves for dark-dwellers and wizards. If
there can be light and continual light, why not infrared light and continual
infrared light, at the same levels of ability and with the same restrictions? A
pebble with continual infrared light would make a dandy lantern that no human
could see, though it would immediately give away itself and its user to any
other infravision-using being within range. A
"light bomb" can be created by enchanting a pebble with continual
light, then coating it with mud. Once dried, the pebble can be carried in a
pouch, emitting no heat at all, until a group of infravision-using foes is met.
The pebble can then be thrown against a wall as the "bomb"-carrier
retreats; the burst of light will temporarily blind the foes and allow for
escape. Optionally, an adventurer with the blind-fighting proficiency could
close his eyes, throw the pebble (probably by the bunch), then attack,
unaffected by the burst of light. A
pebble enchanted with continual infrared light could be used as a signalling
device invisible to normal sight. Placed inside a lantern with a shutter, the
pebble's radiance can be blocked or revealed by opening and closing the shutter.
Given a form of Morse code, underground creatures could signal to each other,
silently and unseen, if surface dwellers approach them. (A
scary thought: In total darkness, a drow can communicate in Morse code with
another drow 240 feet away merely by blinking her eyes. Think about it!) A
pouch full of cold dust would be useful for detecting approaching foes. When
scattered on the ground, the perpetually low-temperature cold dust would quickly
reveal the exact location of any being walking over it, even if the being were
cold-blooded. (The cold dust would be much colder than the surrounding
environment, providing great contrast.) Finally,
a game rules variant: sighting ranges for different sizes of target creatures.
This will complicate the game a bit, but I've tried to keep the basics simple. First,
find the infravision range of the spotter (30 feet, 60 feet, etc.). Next, find
the size category of the target (Tiny, Small, Man-sized, Large, etc.). Multiple
the infravision range by the sighting range modifier, and that's how far the
target must be before it is normally seen. It's thus harder to spot a rat with
infravision than it is to spot an ogre, and you can see the ogre coming from
farther away. Target's
size Spotter's sighting category
range modifier Tiny
1/3 Small
normal Man-sized
normal Large
normal Huge
4 Gargantuan
10 Using
this table, a dwarf can see a hill giant (Huge) coming from 240 feet away, since
the giant is so big and puts out so much heat. A goblin won't be able to see a
rat (Tiny), however, until the rat is 20 feet away. Last thoughtsInfravision
is not the only special sense that real-world and fantasy creatures have.
Minotaurs and hell hounds have superb senses of smell (as do normal canines),
bats use ultrasonic sonar, certain fish sense pressure changes in the water, and
electric eels sense nearby electric fields, such as those from other fish. A
little research and some imagination could bring these other peculiar senses to
life just as this article has hopefully done for infravision. It's a strange
world, and fantasy makes it all the stranger (and more fun). |
|
E-mail me @ xthulhu@crosswinds.net Planescape, Advanced Dungeons & Dragons, Etc... are the Trademarked property of TSR Inc. a subsidiary of WOTC |
