EDITED: 5/11/2017.
While Toady offered a correction (to a misconception I had) in part of his May 2017 FotF reply, indicating that ambusher (still) "matters in all the visual rolls...", it isn't what primarily determines your character's stealth. The core component of your character's detectability is their
Visual Stealth (w/o skill), which is the result of various
visual stealth factors.
There are five
visual stealth factors of differing degree (press
shift +
S to view as you would to change movement speed). The most commonly seen:
1.
Light, Low Light, Darkness. Light level is determined by being
aboveground or
underground, time of day and the
visibility of celestial bodies (stars, sun, moon phase).
2.
Clear, Fog/Rain/Snow. The absence or presence of weather conditions.
3.
Open, By Obstacle. Whether a character is
orthogonal to an adjacent column, door, tree, or wall tile.
4.
No Suitable Vegetation, In Vegetation. Based on occupying a
crop or
shrub tile. Can be negated by an extreme in character sizing (elephant person).
5.
Average Non-Prone Profile,
Very Small Profile or
Tiny Profile. This is character size relative to position (whether standing or on the ground). To differentiate, dwarves, elves and goblins of
large size, and humans of
average size have
very small profiles when on the ground. Dwarves, elves and goblins of
average or small size, and humans of
small size have
tiny profiles when on the ground.
Visual Stealth (w/o skill) levels from highest to lowest:
Best PossibleFantasticGreatGoodAveragePoorAwfulTerribleWorst PossibleLight level and character size have the most influence on visual stealth (w/o skill). While
darkness alone can raise visual stealth level up to
great (
low light can do so as well, albeit more conditionally), isolated usage does not scale well.
Lime green or
cyan colored visual stealth factors work best in combination.
Aboveground nighttime's
low light becomes
darkness under the right weather conditions.
Darkness and small size's
tiny profile allow a character to reach
best possible. The other sizes in combination with
low light or
darkness require one or two additional visual stealth factors to reach similar heights. However, a combination without light level management never scales beyond
fantastic.
Use of
fantastic or
best possible level of visual stealth (w/o skill) can confer virtual invisibility provided conscientious interaction with an NPC's
view range (whose tile count at night is determined by their
low light vision), the nature of their
vision arc, the quality of their
observer skill, their movement behavior, and in a few cases, whether they happen to be
lair hunters.
Full utility for your own character will be limited to their low light vision rating. For playable vanilla Adventure Mode species, only dwarves have the full 25 tile view range in low light or darkness. Humans and elves are limited to 4 tile view range, and goblins to 8 tiles in low light or darkness. Diminished view range in low light or darkness primarily affects dedicated archers versus creatures with
EXTRAVISION and to a lesser degree, bandit camp/bandit hamlet scouting. As with anything else, there's always a way to play around a deficiency.
Quite likely there's a bit more to this, having skipped most intelligent animal creatures, but this is it for now.