Environmental Rules | Game Mastering | Starfinder SRD | Glasstop Games

Environmental Rules

The following is a compilation of rules appropriate for use in a variety of environments.

Cold Dangers

Cold and exposure deal nonlethal damage to the victim. A character can’t recover from the damage dealt by a cold environment until she gets out of the cold and warms up again.

An unprotected character in cold weather (below 40° F) must succeed at a Fortitude save each hour (DC = 15 + 1 per previous check) or take 1d6 nonlethal cold damage. A character can attempt Survival skill checks to gain a bonus to this saving throw and might be able to apply this bonus to other characters as well.

In conditions of severe cold (below 0° F), an unprotected character must succeed at a Fortitude save every 10 minutes (DC = 15 + 1 per previous check) or take 1d6 nonlethal cold damage. A character can attempt Survival skill checks to gain a bonus to this saving throw and might be able to apply this bonus to other characters as well.

Extreme cold (below –20° F) deals 1d6 lethal cold damage per minute (no saving throw). In addition, a character must succeed at a Fortitude save (DC = 15 + 1 per previous check) each minute or take 1d4 nonlethal cold damage. Colder environments can deal more damage at the GM’s discretion.

A character who takes any damage from cold or exposure is beset by frostbite or hypothermia (same as fatigued). These penalties end when the character recovers the nonlethal damage she took from the cold and exposure.

Ice

Icy surfaces count as difficult terrain, and the DCs for Acrobatics checks attempted on ice increase by 5. Characters in prolonged contact with ice might run the risk of taking damage from severe cold.

Falling

A character that falls takes 1d6 damage per 10 feet fallen, to a maximum of 20d6. A character that takes damage from a fall lands prone.

If a character deliberately jumps instead of merely slipping or falling, the damage is the same but the first 1d6 is nonlethal damage. On a successful DC 15 Acrobatics check, the character avoids taking damage from the first 10 feet fallen and converts the damage from the second 10 feet to nonlethal damage. For example, a character who slips from a ledge 30 feet up takes 3d6 damage. If the same character deliberately jumps, he takes 1d6 nonlethal damage and 2d6 lethal damage. And if the character leaps down with a successful DC 15 Acrobatics check, he takes only 1d6 nonlethal damage and 1d6 lethal damage from the plunge.

The damage from the first 10 feet of a fall onto a yielding surface (such as soft ground or mud) is converted into nonlethal damage. This conversion is cumulative with damage reduced through deliberate jumps and successful Acrobatics checks.

A character can’t cast a spell or activate an item while free- falling unless the fall is greater than 500 feet or the spell or item can be used as a reaction. Casting teleport or a similar spell while falling doesn’t end the character’s momentum; it just changes her location, meaning that she still takes falling damage, even if she arrives atop a solid surface.

Falling and Gravity

The rules for falling presented here assume standard gravity. For planets with high or low gravity, double or halve the damage amounts, respectively. Falling in extreme gravity deals as least triple the listed damage, and potentially even more.

Falling into Water

Falls into water are handled somewhat differently. If the water is at least 10 feet deep, a falling character takes no damage for the first 20 feet fallen and 1d3 nonlethal damage per 10-foot increment for the next 20 feet fallen. Beyond that, falling damage is lethal damage as normal (1d6 per additional 10-foot increment).

A character who deliberately dives into water takes no damage with a successful DC 15 Athletics check or DC 15 Acrobatics check, as long as the water is at least 10 feet deep for every 30 feet fallen. The DC of the check increases by 5 for every 50 feet of the dive.

Falling Objects

Just as characters take damage when they fall more than 10 feet, so too do they take damage when they are hit by falling objects.

An object that falls upon a character deals damage based on its size and the distance it fell. Table 11–7: Damage from Falling Objects determines the amount of damage dealt by an object based on its size. Note that this assumes the object is made of dense, heavy material, such as metal or stone. Objects made of lighter materials might deal as little as half the listed damage, subject to the GM’s discretion. For example, a Huge boulder that hits a character deals 6d6 bludgeoning damage, whereas a Huge wooden wagon might deal 3d6 bludgeoning damage. In addition, if an object falls less than 30 feet, it deals half the listed damage. If an object falls more than 150 feet, it deals double the listed damage. Note that a falling object takes the same amount of damage as it deals.

Dropping an object on a creature requires a ranged attack against its KAC. Such attacks generally have a range increment of 20 feet. If an object falls on a character (instead of being thrown), that character can attempt a DC 15 Reflex save to take half damage if he is aware of the object. Falling objects that are part of a trap use the trap rules instead of these general guidelines.

Table: Damage from Falling Objects
Object SizeDamage
Tiny or smaller1d6
Small2d6
Medium3d6
Large4d6
Huge6d6
Gargantuan8d6
Colossal10d6

Gravity

Gravitational differences between planets have the potential to cripple characters or make them superheroes—and sometimes both at the same time. Most planets habitable by humanoids have a gravity level defined as standard, which makes them similar enough that trying to arbitrate the difference isn’t necessary. Others, however, require special consideration. For planets with gravities that aren’t quite standard but don’t fall into the exact categories below, the GM might decide to assume the effects are proportional. For example, a planet with half standard gravity allows player characters to jump twice as high, whereas one with 1-1/2 standard gravity cuts jump heights by a third. In all cases, these effects last until the PCs adjust to the gravity (a process that typically takes about a month of living under such conditions). See Flying for information about flying on planets with high or low gravity.

Extreme Gravity

A planet where the gravity is at least five times as strong as standard gravity is extremely dangerous to most creatures. In addition to the limitations of high gravity (see below), a creature in this environment takes an amount of nonlethal bludgeoning damage per round (at least 1d6, but potentially more, depending on the intensity of the gravity). Once a character takes sufficient nonlethal damage to be reduced to 0 Hit Points, any further damage from extreme gravity is lethal bludgeoning damage.

High Gravity

On high-gravity worlds, characters are burdened by their increased weight, and their physical abilities are affected accordingly. On a high-gravity world, where the gravity is at least twice as strong as standard gravity, a character (and her gear) weighs twice as much as on a standard-gravity world, but she has the same amount of strength. Such characters move at half speed, can jump only half as high or as far, and can lift only half as much. Thrown weapons (though not those of natives) have their ranges cut in half as they fall to the ground more rapidly. Modifications to running, jumping, and lifting can be negated by certain magic or technology, but projectiles remain affected. Characters who remain in a high-gravity environment for long periods (more than a day) often become fatigued and remain so until they leave the planet or become accustomed to the gravity.

Low Gravity

Low-gravity worlds are liberating to most species acclimated to standard-gravity worlds. Such characters’ muscles are far more effective than normal. On a low-gravity world, where the gravity is no greater than a third of standard gravity, PCs can jump three times as high and as far and lift three times as much. (Movement speed, however, stays the same, as moving in great bounds is awkward and difficult to control.) Thrown weapons have their range categories tripled.

Standard

Standard-gravity worlds have gravity approximately the same as that of lost Golarion, which is identical to Earth’s gravity.

Zero Gravity

Movement in zero gravity (also referred to as zero-g) is not the same as flight. Controlled movement is difficult without some form of propulsion, and creatures without something to push off from often find themselves floating aimlessly. A creature in a zero-gravity environment can’t take move actions to move its speed, crawl, or take a guarded step. If a creature is adjacent to or in the same square as an object (including a wall, floor, or ceiling) or another creature one size category smaller than itself or larger, it can take a move action to push off that object or creature, moving at half its land speed in a direction of its choosing (as appropriate); if that object or creature is movable, it begins moving in the opposite direction at that same speed.

  • Moving in Zero-G: A creature that moves in a given direction continues to move in that direction at the same speed at the beginning of its turn each round (without taking any action); it must move the full distance unless it is able to change its motion by latching on to an object or creature, pushing off in a new direction, or creating thrust of some kind (all of which are considered move actions). If a creature runs into a solid object during its movement, it must succeed at a DC 20 Acrobatics or Athletics check to safely stop its movement; failure means that creature gains the off-kilter condition. If a creature runs into another creature during its movement, both creatures must each attempt a DC 20 Acrobatics or Athletics check to avoid gaining the off-kilter condition. A creature anchored to a solid object (such as by the boot clamps available with most armor) receives a +4 bonus to this check. An off-kilter creature in a zero- gravity environment can steady itself as a move action that requires a surface to grab on to or some method of propulsion; alternatively, that creature can throw a single item weighing at least 4 bulk (for Medium creatures; 2 bulk for Small creatures) to reorient itself and remove the off-kilter condition.

    If provided with sufficient handholds, a creature with a climb speed can move along a wall at full speed, as can any creature that succeeds at a DC 20 Acrobatics or Athletics check. Creatures that fly via methods that require an atmosphere, such as wings or turbofans, can’t use their fly speeds in a vacuum; once they reenter an atmosphere, they can recover and get their bearings within 1d4 rounds, after which they can fly normally. Magical flight and methods of flight that provide their own thrust, such as maneuvering jets, are not affected. A character in a zero-gravity environment can lift and carry 10 times her normal amount.

  • Weapons: Thrown weapons have their range increments multiplied by 10 in zero-g. In addition, all ranged weapons no longer have a maximum number of range increments—their wielders simply continue to accrue penalties the farther away the target is.

Heat Dangers

Heat deals nonlethal damage to the victim. A character can’t recover from the damage dealt by a hot environment until she gets out of the heat and cools off.

A character in very hot conditions (above 90° F) must attempt a Fortitude saving throw each hour (DC = 15 + 1 per previous check) or take 1d4 nonlethal fire damage. Characters wearing heavy clothing or armor of any sort take a –4 penalty to their saving throws. A character can attempt a Survival check to receive a bonus to this saving throw, and might be able to apply this bonus to other characters as well.

In severe heat (above 110° F), a character must attempt a Fortitude saving throw once every 10 minutes (DC = 15 + 1 per previous check) or take 1d4 nonlethal fire damage. Characters wearing heavy clothing or armor of any sort take a –4 penalty to their saves. A character can attempt a Survival check to receive a bonus to this saving throw and might be able to apply this bonus to other characters as well.

Extreme heat (air temperature over 140° F, boiling water, fire, and lava) deals lethal fire damage. Breathing air in extreme heat deals 1d6 fire damage per minute (no saving throw). In addition, a character must attempt a Fortitude saving throw every 5 minutes (DC = 15 + 1 per previous check) or take 1d4 nonlethal fire damage. Hotter environments can deal more damage at the GM’s discretion.

A character who takes any damage from heat exposure suffers from heatstroke (same as the fatigued condition). These penalties end when the character recovers from the nonlethal damage she took from the heat.

Boiling water deals anywhere from 1d6 to 10d6 fire damage per round of exposure, depending on water temperature and level of immersion.

Catching on Fire

Characters exposed to burning oil, bonfires, and noninstantaneous magical fires might find their clothes, hair, or equipment on fire. Spells or technological items with an instantaneous effect don’t normally set a character on fire, since the heat and flame from these come and go in a flash.

A character at risk of catching fire must succeed at a Reflex saving throw (usually DC 15) or gain the burning condition. Those whose clothes or equipment catch fire must attempt a separate Reflex saving throw (at the same DC) for each item. On a failed saving throw, flammable items take the same amount of damage as the character.

Lava Effects

Lava or magma deals a minimum of 2d6 fire damage per round of exposure, while cases of total immersion (such as when a character falls into the crater of an active volcano) deal upward of 20d6 fire damage per round. The exact damage is left to the GM’s discretion, based on situational terrain elements.

Damage from lava continues for 1d3 rounds after exposure ceases, but this additional damage is only half of that dealt during actual contact (that is, 1d6 or 10d6 per round). Immunity or resistance to fire serves as an immunity or resistance to lava or magma. A creature immune or resistant to fire might still drown if completely immersed in lava (see Suffocation and Drowning).

Radiation

Radiation is a very real threat to adventurers, whether it’s the radiation emitted from stars or the radiation generated by various technological wonders of the universe. Radiation is a poison effect that weakens an affected creature’s Constitution and can also inflict an affected creature with a disease called radiation sickness. Radiation dangers are organized into four categories: low, medium, high, and severe. The effects of these categories of radiation are described on Table 11–8: Radiation Levels.

Area of Effect

Radiation is an emanation poison, meaning that a victim only needs to enter an area suffused with radiation to be affected by it. Radiation suffuses a spherical area of effect that can extend into solid objects. The closer one gets to the center of an area of radiation, the stronger the radiation effect becomes. Radiation entries list the maximum level of radiation in an area, as well as the radius out to which this radiation level applies. The radiation continues to suffuse each increment out to an equal length beyond that radius, its strength degraded by one level per increment. For example, a spherical area of high radiation with a radius of 20 feet creates a zone of medium radiation spanning 20 feet to 40 feet from the center in all directions, and a similar zone of low radiation spanning 40 to 60 feet from the center.

Curing Radiation Effects

A creature that leaves an area suffused with radiation is essentially cured of the poison effect. Ending the source of radiation or successfully casting remove radioactivity has the same effect. As usual for poison effects, an affected creature requires rest to recover from radiation poisoning. Remove affliction doesn’t cure a creature of the effects of radiation poisoning, but remove radioactivity does.

If a creature has been exposed to enough radiation, it might contract radiation sickness, which acts like a noncontagious disease. Symptoms of radiation sickness include nausea, vomiting, and loss of hair. Radiation sickness can be treated like any disease, although it can’t be cured with remove affliction. Remove radioactivity can cure radiation sickness.

Radiation

Type poison, emanation (see above); Save Fortitude (see chart)

Track Constitution; Frequency 1/round

Effect At each state of impaired and beyond, the victim must succeed at a DC 18 Fortitude saving throw or contract the radiation sickness disease (see below).

Cure none

Radiation Sickness

Type disease; Save Fortitude (same DC as the level of radiation that caused the radiation sickness)

Track physical; Frequency 1/day

Effect Radiation sickness isn’t contagious. Cure 3 consecutive saves

Table: Radiation Levels
Radiation LevelFortitude DC
Low13
Medium17
High22
Severe30

Sleep Deprivation

A character who needs to sleep must get at least 6 hours of sleep every night. If she doesn’t, she must attempt a Fortitude save (DC = 15 + 1 per previous check) after each night she doesn’t sleep enough. The first failed check causes her to become fatigued and take a –1 penalty to saving throws against effects that cause the asleep condition. A second failed check causes her to become exhausted, and the penalty to saving throws against effects that cause the asleep condition increases to –2.

Smoke Effects

A character who inhales heavy smoke must attempt a Fortitude save each round she’s within the smoke (DC = 15 + 1 per previous check) or spend that round choking and coughing. A character who chokes for 2 consecutive rounds takes 1d6 nonlethal damage. Smoke obscures vision, giving concealment (20% miss chance) to characters within it.

Starvation and Thirst

Characters might find themselves without food or water and with no means to obtain them. In normal climates, Medium characters need at least a gallon of fluids per day to avoid thirst and about a pound of decent food per day to avoid starvation; Small characters need half as much. In very hot climates, characters need two or three times as much water to avoid thirst.

A character can go without water for 1 day plus a number of hours equal to his Constitution score. After this time, the character must succeed at a Constitution check each hour (DC = 10 + 1 per previous check) or take 1d6 nonlethal damage.

A character can go without eating food for 3 days. After this time, the character must succeed at a Constitution check (DC = 10 + 1 per previous check) each day or take 1d6 nonlethal damage.

A character who has taken any damage from lack of food or water is fatigued. Damage from thirst or starvation cannot be recovered until the character gets food or water, as needed—not even magic that restores Hit Points heals this damage.

Suffocation and Drowning

A character who has no air to breathe can hold her breath for a number of rounds equal to twice her Constitution score. If a character takes a standard or full action, the remaining duration that the character can hold her breath is reduced by 1 round. After these rounds have elapsed, the character must attempt a Constitution check (DC = 10 + 1 per previous check) each round in order to continue holding her breath.

When the character fails one of these Constitution checks, she begins to suffocate. In the first round, she is reduced to 0 Hit Points and is unconscious and stable. In the following round, she is no longer stable and begins dying. In the third round, she suffocates and dies.

An unconscious character must begin attempting Constitution checks immediately upon losing air supply (or upon becoming unconscious, if the character was conscious when her air was cut off). Once she fails one of these checks, she immediately drops to 0 Hit Points and is dying. On the following round, she suffocates and dies.

Slow Suffocation

A Medium creature can breathe easily for 6 hours in a sealed cubic chamber measuring 10 feet on a side. After that time, the creature takes 1d6 nonlethal damage every 15 minutes.

Each additional Medium creature or significant fire source (a torch, for example) proportionally reduces the time the air will last (two Medium creatures will run out of air in 3 hours, and so on). Small characters consume half as much air as Medium characters. A creature stuck in a starship or space station whose life support systems have completely failed will run out of breathable air in a similar fashion; while these structures are often larger than a 10-foot cube, they are also often occupied by several creatures. On average, a crew of four in a Medium starship without a source of fresh air can breathe easily for 20 hours.

Underwater Combat

Land-based creatures usually have considerable difficulty when fighting in water, as it affects a creature’s attack rolls, damage, and movement. The following adjustments apply whenever a character is swimming, walking in chest-deep water, or walking along the bottom of a body of water.

Attacks from Land

Characters swimming or floating in water that is at least chest deep and characters who are fully immersed have cover against attacks made from the surface.

Attacks Underwater

Most attacks made underwater take a –2 penalty and deal half damage. Attacks that deal fire damage do only one-quarter damage. Attacks that deal electricity damage take a –4 penalty rather than a –2 penalty. Melee attacks that deal piercing damage deal full damage. Thrown weapons are ineffective underwater, even when launched from land.

Spellcasting Underwater

A creature that is attempting Constitution checks to hold its breath can’t concentrate enough to cast spells. Some spells might work differently underwater, subject to the GM’s discretion.

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