PCs and Enemies noticing each other

[CptMuffinCubes]

Could anyone give me a sequential order play listing the mechanics when it comes to things like monsters and PCs noticing each other? As a referee, I want to confidently be able to determine if the PCs and the monsters notice each other, rules as written. Page references would be handy. Here are some examples that come to mind that I can easily think will come up in play.

1) The PC group and monster group are walking through the woods with decent lighting. Neither party is scouting ahead. How do I determine if the two groups notice each other? To add complexity, let's say there is 1 Thief in the party, how might that affect how the situation unfolds? Let's also say there is 1 halfling in the party, how might hiding in this situation work?

2) A thief scouts ahead and tries to move quietly, unseen. If there are guards ahead, manning their post, should he see them automatically? If the thief fails his 'move silently' check, will the guards automatically notice the thief? Is there a check of some sort? Is there an opportunity for 'hide' to be used here?

I understand that there is some leeway here for the referee to make some rulings, but I'm looking for some very dry, straightforward interpretations of the rules as written to make sure I understand the mechanics.

[Metroknight]

Could anyone give me a sequential order play listing the mechanics when it comes to things like monsters and PCs noticing each other? As a referee, I want to confidently be able to determine if the PCs and the monsters notice each other, rules as written. Page references would be handy. Here are some examples that come to mind that I can easily think will come up in play.

1) The PC group and monster group are walking through the woods with decent lighting. Neither party is scouting ahead. How do I determine if the two groups notice each other? To add complexity, let's say there is 1 Thief in the party, how might that affect how the situation unfolds? Let's also say there is 1 halfling in the party, how might hiding in this situation work?

If the thief is not scouting ahead then you would use the surprise rules (page 43/pdf page 47) which is a 1d6 roll with modifiers based on race and situation. The halfling's hiding ability only works if they are not moving but in your example everyone is walking so that does not come into play. The example in the book is very similar to what you are asking about.

2) A thief scouts ahead and tries to move quietly, unseen. If there are guards ahead, manning their post, should he see them automatically? If the thief fails his 'move silently' check, will the guards automatically notice the thief? Is there a check of some sort? Is there an opportunity for 'hide' to be used here?

I understand that there is some leeway here for the referee to make some rulings, but I'm looking for some very dry, straightforward interpretations of the rules as written to make sure I understand the mechanics.

If the thief succeeds in the appropriate rolls, he is not seen and/or heard (GM judgement call for the modifiers due to description of the attempt, environment of the scene, etc and what thief skills are required). If the thief fails his roll then the GM can have the guards automatically notice the thief or he can decide to use the surprise rule mechanic to represent the guard's awareness.

In a game of mine, the example you laid out would go mechanically as following
1)Thief makes a hide and move silently skill check. (GM would make the roll as the player should not know if they succeed or not).
2)If the roll(s) are a success then the guards are unaware.
3)If the roll(s) are a failure then the guards make a surprise check.
4)If the guards fail their surprise check, they are unaware of the thief at that moment.
5)If the thief moves again, go back to #1 and start the process all over again.

[CptMuffinCubes]

If the thief fails his roll then the GM can have the guards automatically notice the thief or he can decide to use the surprise rule mechanic to represent the guard's awareness.

4)If the guards fail their surprise check, they are unaware of the thief at that moment.

Thanks for the numbered sequence of play and your detailed response.

I seem to remember reading situations where you use the surprise rules in a situation that you describe but I can't remember where.

So normally, surprise is treated like this:
Succeed = Monster is ready to fight/act
Fail = Monster Surprised (does not act for 1 combat round)

The way you're using it would be:
Succeed = Monster notices you in the distance. Monster may act accordingly.
Fail = Monster does not notice you in the distance. Monster is not necessarily "surprised" (unable to act). Or is it?

What would be the frequency that the monsters would roll surprise checks if the thief tries to creep past them?

[Metroknight]

So normally, surprise is treated like this:
Succeed = Monster is ready to fight/act
Fail = Monster Surprised (does not act for 1 combat round)

correct

The way you're using it would be:
Succeed = Monster notices you in the distance. Monster may act accordingly.
Fail = Monster does not notice you in the distance. Monster is not necessarily "surprised" (unable to act). Or is it?

What would be the frequency that the monsters would roll surprise checks if the thief tries to creep past them?

The method described happens when the thief fails their skill roll.
How many times in the movies do you see the hero step on a branch or bump a tin can with their foot only to have the guard not notice or just shrug off the sound? That is an example of the thief failing their roll and the guard failing their surprise check.

The frequency of the surprise checks would depend on how you want to handle it as it is your game. Official rules usually imply that the thief fails his roll, he/she is noticed but when you factor in the surprise check (usually used once) that changes the play somewhat.

Example:

Felix the thief is trying to sneak past some Orc guards at the front of a cave mouth. The GM decides that he will need two rolls in his attempt to pass the guards. The first roll is a success and Felix makes it all the way to the mouth of the cave without being noticed.

The second roll is a failure. The GM decides to roll to see if the guard notices Felix (surprise check) and the guard fails it's roll (does not react to the fact Felix is behind him). Now the player of Felix has to decide. Does he continue sneaking past the guard without knowing if the guard spotted him or risk combat?

[Dimirag]

NOTE: In the case of surprise, a hidden thief will get a +2 in his surprise chances, you could use this approach on any situation where a roll is made and the thief is using one of his skills successfully, now, this won't work on rolls against the character, for such situations you can increase the die size by 2, rolling a d10 against the thief instead of a d6.

1) The PC group and monster group are walking through the woods with decent lighting. Neither party is scouting ahead.

These are the way I would probably rule it.

How do I determine if the two groups notice each other?

If both are alert of their surroundings then there is no roll, they see something in the distance. If one or both parties are not paying full attention, then a roll is in order, 1 in 6 chances, +1 if elf, and +1 if Wisdom is 15 or better.

To add complexity, let's say there is 1 Thief in the party, how might that affect how the situation unfolds?

If he is moving alongside the party, it has no extra benefits, if he is moving while hiding he is treated individually:
-If he is hiding successfully: no chance of finding him unless you use the rule above, in which case he has a 1 in 10 chances of been detected.
-If he fails to do it: treated as previous answer.

Let's also say there is 1 halfling in the party, how might hiding in this situation work?

His chances of hiding are only while not moving, and I would treat it as the thief above, otherwise he is like any other party member.

2) A thief scouts ahead and tries to move quietly, unseen. If there are guards ahead, manning their post, should he see them automatically?

Moving quietly does not mean moving unseen, the place should provide some cover for the thief to try to hide or move undetected.

If the thief fails his 'move silently' check, will the guards automatically notice the thief? Is there a check of some sort?

No, the thief will move like any other character and have the same base chance of detection.

Is there an opportunity for 'hide' to be used here?

Hide is needed to not been seen, and largely depends on the environment, not every time a thief will be able to try to hide.

[orobouros]

In a module I'm putting together right now I wanted a bit more structure to such encounters and added my own table. The core rules really only specify if one side is surprised, the details left to the GM.

For me, I have a 2d6 table (since this weighs things towards 7), with different degrees of meeting. 7 is neutral. 5/6/8/9 are neutral but one side gets a bonus on initiative if combat breaks out immediately. 3/4/10/11 and one side is surprised. At 2/12 one side notices the other, but they have no idea they've been spotted.

Note however this is specifically for encounters in some long unlit hallways and is a mechanic of the particular encounter I'm planning; I wouldn't apply this to general encounters, since walking into a room with guards makes certain of these outcomes untenable.

But the point is, it's really your discretion.