The Environment
The environment you find yourself doing your activities in can greatly impact the way you do these things. This page is here to describe a few of the basic attributes a location might have. They might rarely come into play, but it is worth giving them a read.
Difficult terrain
Some encounters take place in spaces that aren’t the easiest to traverse – whether it be because of piles of snow, abundance of furniture, shallow ponds, mud banks, steep inclines, or anything else in the way. That kind of terrain is considered to be difficult terrain.
When you move through difficult terrain, each foot of movement costs you an extra foot of movement – effectively halving your movement speed. The space of another creature, regardless of if it is hostile of not, is also considered difficult terrain.
Difficult terrain can have a stacking effect. That means, when several effects make an area difficult terrain, that means you have to use an extra foot of movement for every single of the effects, not just one increase for all of them.
Cover types
Walls, trees, structures, big creatures and other obstacles can provide cover, making a target more difficult to harm. A target can only benefit from cover if the attacker is on the opposite side of the cover – meaning the cover is actually between the attacker and target (otherwise the cover won’t do much).
There are two types of cover – half cover and total cover.
A creature is considered to have half cover if at least half their body is obstructed. The target gains +2 to their AC and Saving (Dexterity) throws. The obstacle in question can be a low wall, a piece of furniture, another creature, a tree or a open window.
A creature is considered to have total cover if it is completely concealed by an obstacle. Such creature cannot be directly targeted by an attack of spell, however some effects can still reach the target by including it in an AoE.
Vision and Light
The most fundamental of the five senses, at least for the majority of people, is sight. Therefore, conditions that obscure vision have an impact on all things that you do, whether it be checking for traps, hitting enemies, or targeting spells.
A given area can be heavily or lightly obscured.
In a lightly obscured area, such as dim light, moderate foliage, or patchy fog, creatures have disadvantage on Ability checks that mainly rely on sight.
A heavily obscured area, such as darkness, opaque fog, or dense foliage, blocks vision entirely. Characters within that area are effectively suffering from the blinded condition.
There are three levels of illumination – bright light, dim light and darkness.
Bright light is normal daylight, even on gloomy days. All sources of light such as fires, torches, lanterns and other provide bright light in a certain radius.
Dim light, also known as shadows, create a lightly obscured area. Dim light is usually found as a boundary between bright light and darkness. Twilight and dawn are also sources of dim light.
Darkness creates a heavily obscured area. Darkness is found outdoors at night (even at most moonlit nights), within unlit dungeons or other structures, or in areas of magical darkness.
Darkvision and Blindsense
Some spells and other abilities give a creature darkvision.
Creatures with darkvision can see in darkness as if the darkness was dim light. However, the creature can’t discern color in darkness, only shades of gray.
Some creatures and spells have blindsight.
Those creatures can perceive their surroundings without relying on sight, to a certain range. As such, conditions like blinded do not affect this sense, unless specifically noted.
Environmental damage
At times, it is not you enemies hurting you, but nature. The two most common causes are suffocating and falling.
When a creature falls from a great distance, it takes 1d6 normal damage for every 10 feet it fell, to a maximum of 20d6. It also lands prone, unless it avoided all the damage from the fall.
A creature falls at a rate of 500 ft. per round.
A creature can hold its breath for a number of minutes equal to its Endurance, minimum of 30 seconds. When a creature runs out of breath, at the start of every round it takes 1d6 normal damage, and the damage increases by 1d6 every consecutive round, up to a maximum of 20d6. This damage ignores immunities and resistances to normal damage, as well as DR provided by armor. The damage also cannot be healed until the creature stops suffocating.