VISION, HEARING, & LIGHT

LIGHT

Infravision, the ability to see radiation in the infra-red spectrum, is an ability possessed by most of the creatures dwelling below ground and nocturnal animals. Some characters have this ability due to race or by magical means. 

However, as many characters can only see in light which is normal to the human visual spectrum, and mapping requires light also, some form of light generating device is necessary for activities in dungeons or at night. The table below gives the properties of the usual light sources:

Mirrors. It is important for DMs to remember that in order to be reflective, a mirror must have a light source.

EFFECTS OF BLINDNESS

INFRAVISION

As previously mentioned, infravision is the ability to see into the infrared spectrum. Thus heat radiation becomes visible and differences in temperature allow infrared sight. Warm things are bright, cool things grey, very cold things are black. Most infravision extends to 60-ft distance.

Dungeon-dwelling monsters have infravision to 120--ft. 

All infravision is spoiled if a light source is shedding illumination upon the creature possessing the infrared sight capability. Similarly, great heat will spoil the capability.

Thieves hiding in shadows are successful with respect to infravision only if there is a heat/light source nearby to mask their body heat, or a very cold object or radiation to provide similar cover.

As explained in PLAYERS HANDBOOK, infravision is the ability to see light waves in the infrared spectrum. Characters and various creatures with intravisual capability out to 60-ft (standard) are basically picking up radiation from their surroundings. Therefore they note differences in thermal radiation, hot or cold. 

They do not "see" things which are the same temperature as their surroundings. Thus, a room in a dungeon might look completely blank, as walls, floor, ceiling, and possibly even some wooden furniture within are all of the same temperature. 

Openings in the walls should show up rather plainly, as space anywhere else will, and if you are generous, you can allow different substances to radiate differently even if at the same temperature, i.e. the wood in the example above would be discernible if care was used in scanning the room infravisually.

Note that air currents might show as cold or warm layers. 

Except where very warm or very cold objects are concerned, vision of this sort is roughly equal to human norm on a dark and cloudy night at best. 

Note also that monsters of a very cold or very warm sort (such as a human) can be tracked infravisually by their footprints. Such tracking must occur within 2 rounds of their passing, or the temperature difference where they had trodden will dissipate.

Light sources which give off heat also absolutely prevent normal infravision from functioning within their sphere of illumination. (Explain this as the effect of trying to see into the dark when the observer is in a brightly lit area.) 

It requires not less than two segments to accustom the eyes to infravision after use of normal vision.

Creatures with infravisual capability of unusual nature, such as those which see infravisually to 90-ft, are actually emitting infrared radiation from their eyes and seeing what is within this visual range by receiving the reflected radiation. 

Such creatures can easily distinguish floor, ceiling, wall, and other areas, as well as furnishings within an area. The eyes of all such creatures will appear as very brightly glowing red when observed by any other creature with standard infravision. 

Most monsters inhabiting underground areas will have this form of infravision.

Infravision outdoors enables the individual to see figures which are warm or cold at 100-ft to 300-ft, depending on temperature extremes. Vision is otherwise equal to a bright, starry night, with full moonlight.

ULTRAVISION

Ultravision is the ability to see radiation in the ultraviolet spectrum—gamma rays, x-rays, etc. Creatures with this ability can see in normal nighttime darkness; that is, they see at night as well as a human can see at dusk because of the continual bombardment of ultraviolet radiation upon the earth.

Ultravision is the ability to see radiation above violet in the normal visible spectrum. 

Unless this ability is of highly unusual nature, so as to be able to see far into this spectrum, ultravision will not be useful underground (where radiation is screened out) without some source of ultravisual emanation. 

Magic weapons which shed illumination spoil ultravisual capability, just as heat does infravision. 

As noted in PLAYERS HANDBOOK, ultravision enables the viewer to see outdoors at night as if he or she were in twilight, so vision extends clearly for about 100 yards, dimly to about 300. On particularly cloudy nights, ultravisual capability is reduced to about half normal, i.e. clear sight to 50 yards, dim to 150 yards.

INVISIBILITY

By various magical means it is possible to become invisible and move about. Invisibility bestowed by a cloak of elvenkind extends to what it covers. A ring or spell of invisibility offers superior invisibility. 

Note that none mask light, so the invisible character cannot move about with a light source and be unseen, for the light will be noticed even though its bearer and possibly its source are not.

"Now I'll sneak up on the monster invisibly!" How often has this cry rung forth from eager players in your campaign? How often have you cursed because of it? Never fear, there are many answers to the problem of invisibility, and most difficulties will be resolved after you read the following rules and suggestions regarding the subject.

Invisibility is not what most players desire it to be. It is neither a soundproofing nor an odor preventative. Normal sound issues from the invisible creature, just as normal odors do. Monsters might well be able to hear, smell, or see the invisible character. Furthermore, the associates of the invisible party are not able to see him or her any better than foes are, so this can cause problems, too. Now consider a silence spell and large area invisibility cast upon a party. Imagine the chaos within the area as characters stub their toes on the heels of the person before them, with the inability to hear anything so that falls, suggestions as to what should be done, or orders cannot be heard. Consider also that dust on the floor will betray most invisibility, as will dust or powder in the air. Think of a door opening without any visible cause; will this cause suspicion in the mind of the viewer (particularly when the surroundings are taken into account!)? You bet it will!

Invisibility spells are broken when attack occurs, but what about devices?

Becoming invisible takes but a twinkling, but if the party is observed doing so, there is no reason why an opponent cannot attack with the standard penalty (-4) for inability to see the target. Likewise, becoming visible takes only a second, but thereafter the foe is able to clearly observe the attacker for a return of the compliment, as it must be assumed that it requires a full round to again activate the magic which enables the character to be non-visible.

Invisibility to animals, the first level druid spell, does not allow attack, but it is pretty well proof against stupid animals. Invisibility devices generally duplicate the spell or else make the user likely to be undetected that turn or round, indetectability being stated as a percentage chance. 

CHECK EACH PERIOD AS APPLICABLE UNDER THE SITUATION. 

Dust of disappearance does not negate sound or odor either, so it is basically the same as an invisibility spell which allows invisible attack. 

In no event is the thief ability to hide in shadows to be treated the same as invisibility as regards disappearance (see CHARACTER CLASSES, THIEF ABILITIES for further details).

Finally, we have the consideration of the ability to detect invisible creatures even though they are not actually seen. This is explainable as the observer's ability to note a minor disturbance in the air — a shimmering or haze — or by keen hearing, and/or keen sense of smell. 

The table below gives the probability of detection of invisibility according to level/hit dice.

Note. You may give unintelligent creatures with keen hearing or sense of smell the equivalent of Intelligence to reflect detection of invisible creatures.

Check each round the creature is exposed to invisibility. 

Once detected, the invisible creature will be kept track of thereafter, as the detector will be able to note the cause. 

Any attacks incur the -4 penalty of attacking an invisible opponent, of course, and the invisible creature likewise is entitled to +4 on saving throws.

FIGHTING AN INVISIBLE OPPONENT

LISTENING AT DOORS

In addition to the simple exercise of observation, many times characters will desire to listen, ear pressed to a perial, prior to opening and entering.

This requires a special check, in secret, by you to determine if any sound is heard. Because of this, continual listening becomes a great bother to the DM. While ear seekers will tend to discourage some, most players will insist on having their characters listen at doors at every pretense. First, make certain that you explain to players that all headgear must be removed in order to listen. Those wearing helmets will probably have to remove a mail coif and padded cap as well, don't forget. The party must also be absolutely silent, and listening will take at least one round.

Silent creatures — undead, bugbears, etc. — will never be heard. Sleeping or resting or alerted creatures will not be heard either. If there is something for the listener to hear behind the door, the following probabilities will determine if any sound is heard:

Keen-eared individuals will gain a bonus of 1 or 2 in 20 (5% or 10%). Use chance of hearing a noise to determine if a character is keen-eared the first time he or she listens at a door, and if it is indicated, tell the player to note the fact for his or her character. Player characters will not initially have hearing problems (as they wouldn't have survived if they had them).

During the course of adventuring, great noise might cause hearing loss.

Handle this as you see fit. A loss of hearing might negate the chance to hear something behind a door without any other noticeable effects.

HEARING NOISE

When a die roll indicates a noise has been heard, tell the player whose character was listening that he or she heard a clink, footstep, murmuring voices, slithering, laughter, or whatever is appropriate. (Of course, some of these noises will be magical, e.g., audible glamer spells, not anything which will be encountered at all!) Be imprecise and give only vague hints; never say,

"You hear ogres," but "You hear rumbling, voice-like sounds." Failure to hear any noise can be due to the fact that nothing which will make noise is beyond the portal, or it might be due to a bad (for the listener) die roll. Always roll the die, even if you know nothing can be heard. Always appear disinterested regardless of the situation.

Maximum Number Of Listeners: Each listener will take up about 2½-ft of space, so up to three can listen at a typical dungeon door.

Maximum Length Of Time For Listening: Only three attempts can be made before the strain becomes too great. After the third attempt, the listeners must cease such activity for at least five rounds before returning to listening again.

SILENT MOVEMENT

Characters typically make a certain amount of noise, and thus alert opponents of their presence. 

But thieves, as well as characters able to move quietly because of a magical device such as boots of elvenkind have a chance to be absolutely silent when moving. This chance to be absolutely silent is given as a percentage, +/- modifiers, and the character must roll percentile dice to score less than or equal to the percentage chance he or she has to move without sound. 

Success indicates silent movement and an improved chance to surprise an opponent or slip past it.