Skill checks for an ambush?

[msherman]

What are the rules for lying in ambush? I've been using straight perception vs. stealth rolls, but it ends up pretty unsatisfying -- because it would always be the worst stealth roll vs the best perception roll, it means that the ambusher pretty much never gets the drop against the prey.

Is there some kind of bonus I should be applying to the ambusher to account for the time they have to prepare their hiding spot? What about for distance -- the only adjustment I see in the PHB is +2 perception DC for more than 10 squares, but that's quite a large tactical penalty for a pretty small bonus, so it's not really worth moving the less stealthy members of the ambushing party that far away.

Note: this has been failing both ways in my game -- I'm having trouble making exciting encounters based around ambushing the PCs because of their ranger's high double digit perception, and the players are also unhappy that two PCs with stealth bonuses in the low single digits mean they can never set a successful ambush against their enemies.

 

[Mort_Q]

I think you may want to play around with passive perception instead of rolling, and allow more situational bonuses and assisting.

As you said, having time to prepare should affect things.

You can always ignore the dice, and let a well thought out ambush by the PCs earn them a surprise round.

 

[Blackbrrd]

Run it as a skill challenge?

Possible outcomes could be:
* Surprise and bonus to initiative (complete success)
* Surprise (success)
* Bonus to initiative (partial success)
* No modifiers
* Penalty to initative (fail)
* Surprised (fail)
* Surprised and penalty to initiative (utter fail)

 

[Infiniti2000]

A skill challenge to me doesn't seem all that satisfying because there are so few skills to use. As Mort_Q mentions, though, isn't passive perception the RAW method? I was sure that's how it's written in the Stealth description (errata-ed). Even so, it certainly is a stealth vs. the best perception. But, I don't see a problem with that. Circumstantial modifiers are definitely your friend, however. I wouldn't go beyond +5 unless there truly are some extraordinary circumstances.

 

[Turtlejay]

Passive perception should be how you are doing this.

Also, perception is more than just spot and listen rolled into one, it is. . perceiving. If your characters *do* set up a good ambush (remain still and quiet, stay downwind, etc) They should get themselves a nice fat bonus to their stealth checks. Same for their adversairies, should they set up an ambush of their own.

Also, a blown ambush may not be a bad thing. Turn it into a trap. The victims move to engage what they think are their opponents, only to have the other half of the army burst out behind them and bwah!

Jay

 

[Mort_Q]

Remember, you know parties skills and abilities. Set the DCs accordingly.

 

[msherman]

Thanks for all the advice.

We prefer to roll their stealth checks for stuff like this -- too many passive checks make the players feel like they aren't in control of their characters. We only use passive checks when they shouldn't know the check even happened if they fail it. That's not the case for an ambush -- either they get surprised and attacked, or they spot the enemy and engage on their own terms, so there's no harm in letting them roll the dice. The math still works out the same on average.

The big question in my mind is, how much bonus to the stealth check should I give the ambusher for having plenty of time to set up and prepare a perfect ambush site?

I'm thinking +5 for preparation with unlimited time, +2 for limited preparation under time pressure, and additionally give the cover/concealment bonus (+2 or +5) for people who have a good concealed hiding spot. And the least stealthy members of the ambushing party will hide 10 squares further back, for an additional +2.

I just set up a couple ambush encounters using those bonuses, and the DCs for them worked out to the 20-25 range, which seems like the right ballpark for a level 6 party, so I think I'm on the right track.

 

[Mort_Q]

T-- too many passive checks make the players feel like they aren't in control of their characters.

Really? I usually notice the opposite. Rolling a 1 on something that should be a given for a trained character.

If they were not in combat, I'd allow them to Take 10.

 

[NotAYakk]

First, the opponents know who is a clutz probably. And lots of cover/distance give a bonus to stealth checks.

Stick the clutzes far away enough to get bonuses to their stealth check, with the high-steath opponents nearer.

Then every opponent's stealth check will be about the same level.

You can also use passive stealth (yes, I know that is strange) for the opponents, and tell the players to roll against the resulting DCs with perception. This is mathematically very close to rolling the opponent's stealth against player's passive perception, but makes the players more active.

As a bonus, if (say) the shaman hiding further away still has a worse stealth modifier than the up-close stealthy ninjas, there will be two DCs -- one to spot the shaman, and a higher one to spot the ninjas. So the players start the fight only knowing about the shaman -- and then the ninjas jump out of nowhere (as all good ninjas should).

 

[Nytmare]

First and foremost, 4th Edition's most frequently missed 3rd Ed step-wunderkinder: Take 20.

Depending on my mood, I'd either give each member of the ambushing group a static stealth +20 (or more likely give the entire group the highest stealth +20 as the DC) and have each possible ambushee roll one perception check against it.

Players who spot the ambush can act in the first round of combat, everyone else is surprised.