D&D 5E DOUBT ABOUT PERCEPTION, SIGHT, HEARING AND SMELL.

[maritimo80]

DOUBT ABOUT PERCEPTION, SIGHT, HEARING AND SMELL. A character is a forest camping and agreed. How many feets away from him with his passive perception (or active, if you are looking for something) can sense an enemy (whether by sight, smell or noise)? That would change in accordance with the terrain. How far in the case of desert, city, cave, closed environment, open space? I am master and the characters are complaining saying "put the enemies too close", ie, active perception only let them act a few meters.

 

[GMMichael]

Ask yourself, "when is the first opportunity that the PC could perceive an enemy?"

When does the enemy make the first detectable noise? Or smell? When is he finally visible?

That's when you make the first roll.

If you're using "Passive Perception," your PCs perceive the enemy when the enemy's DC equals the PC's PP.

Use the recommended DCs for each environment (city, cave, desert) again, by thinking about when the PC would notice:
10 = easy
15 = hard
20 = very hard (no, I don't have the PH right in front of me...)

 

[aramis erak]

I'll give an example from my session yesterday...

Players sneaking across a field by daylight, near a cave. Being in the cave entry has passive perception 10. Their worst sneak is a 9. So, yes, being in cave spots them. It tries to sneak away from the cave entry, rolls a total of a 7. The best PC's passive perception is a 14, so, yes, they spot it retreating - just a glimpse, because of distance. In fact, everyone spotted some motion, except the thief, who was the only one with a Passive Perception below 12.

 

[Paraxis]

When the party tries to sneak someplace you are supposed to use the group checks on page 175 of the PHB. So if half or more of the party exceeds the passive perception of the guards then they should sneak up on them.

I like players to roll dice in situations like this, so if the players are on watch, I would use passive stealth of the ambushers vs active perception checks.

The reason to use group checks is if you have 5 or 6 players all roll sneak, odds are one of them is going to roll like crap every single time.

 

[Stormonu]

When in doubt, the 1E DMG Encounter distance rules can be a good start:

When encounters occur, the distance between concerned parties will be 50 to 100 feet (d6 + 4 x 10) subject to the following modifying factors:

1. Line of Sight: If this is unobstructed and light is involved, the distance possible for determination of another party present is virtually infinite. It could likewise be sharply restricted due to obstructions.
2. Noise: If one party is making considerable noise which is discernible by the other party, the latter will have the options of fleeing or concealment; the former negating the encounter, the latter allowing distance to be 10 to 40 feet before discovery by the noisy party.
3. Actual Area: If the encountered party is in a small area, distance between the two can be no greater than the maximum distance possible
for discovery of the one by the other, i.e. opening a door into a 20 ft. X 20 ft. room will mean the distance between the two parties can be under
10 feet, 10 feet or thereabouts, or 20 feet (d6, 1-2 = striking distance, 3-4 = 10 ft. distance, 5-6 = 20 ft. distance).
4. Planned or Unplanned Appearance: The sudden precipitation of one party upon the other due to any of a number of factors (teleportation,
dimension door spell, other magical means, a chute, etc.) will cause distance similar to that found when actual area is a factor.
5. Surprise: Surprise can only be a factor in close encounter situations. If either or both parties are surprised, the distance must be either 10 to 30 feet
or it must be less as determined under the actual area modifier. Thus if the actual area were a 40 ft. X 60 ft. room, if surprise exists the distance
between the parties will be 10 to 30 feet.
6. Light: The illumination factor or visual capability of the concerned parties will affect encounter distance as follows:
A. A light source reliance limits the encounter distance to twice the normal vision radius of the source (2 X radius of the light source).
B. [darkvision] operate only to the stated limit of their range and limit encounter distance accordingly.