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> How do you determine if a character has been spotted?, Perception tests under various circumstances
Wounded Ronin
post May 24 2008, 07:35 PM
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One sort of issue I used to have back when I used to GM was how to determine whether or not a character has been spotted. In principle, yes, you use a perception test, but the way that perception tests work was so open ended that I always felt that it would be hard to be fair and consistient. Let me give you a few examples of situations where I'd feel a bit uncomfortable with the perception test mechanic.

Let's say that a shadowrunner, pictured here, is lying prone 500 meters away from a platoon of 30 UCAS marines and is observing them through binoculars. How do we handle the perception tests the marines get to notice him? Does each marine get to roll Perception against some high TN to have a chance to notice the shadowrunner? If so, even if we assume that all the marines have average intelligence, that would add up to 30 rolls of 3 dice, or 90 rolls alltogether. Even if the TN to spot the shadowrunner is around 15-20 it seems likely that the shadowrunner would be spotted, since there are so many rolls taking place. But I'm not sure if that's satisfactory or realistic because it means that the best defense against stealth is just to have many many people present since this adds up to more dice rolls.

Secondly, would the marines immediately know the shadowrunner is there and be able to open fire on him if they got a single success? If not, what would one success mean? They sense a disturbance in the force? How many successes would they need to be able to open fire? I'm not sure how satisfactory it would be in the circumstances described to have the shadowrunner observe the marines from 500 meters way for 3 seconds and then within those three seconds a few of the marines aimbot-spin to squeeze an aimed burst at him.

Thirdly, given that a combat turn is only 3 seconds, how many combat turns should pass before the marines who didn't notice the shadowrunner are allowed to open fire on him? Again, my concern would be the surreal situation where at 500 meters within the first 3 seconds a few marines are firing on the shadowrunner, and then 3-6 seconds later following a few "speak a word" actions all 30 marines are firing aimed bursts at the shadowrunner so again by probability he likely gets ripped to shreds. I'm not a military expert but or anything but it seems a bit strange that looking at a platoon through binoculars for 6 seconds would result in instant death.

Since DSF knows all the rules, what is the "correct" way to handle perception tests in the situation described above?
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Teulisch
post May 24 2008, 07:58 PM
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find the base DP of the guards for perception, then either subtract 2 for distraction(normally), or add 3 for activiely looking (if an alarm went off a moment ago). next, figure out vision penalties(page 117) and apply those. then just buy hits for the guards, and if they exceed the stealth roll of the runner (or if the runner glitches) then they see him...

wait, is that beastmaster with a gun?

once the runner is spotted, the reaction depends on what the standing orders of the guards are. this will vary greatly from one installation to the next. some will be trained to open fire at once, while others will radio for support, while moving to intercept the threat. a squad which is too far to engage a target should adjust their response based on the range of their weapons, and where cover can be found.

i would give the 'didnt notice' guys one combat turn of going "huh, what? where?" before they catch on. if your buddy is pointing out a threat, your going to respond as fast as you can, but it will take an action to look where hes pointing.

exact specifics will depend on how you want to run your game. some GMs will roll every guy, but if your going to roll a group, you may as well only have one guy roll for that team.
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hyzmarca
post May 24 2008, 08:22 PM
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That depends on if you have an automated dice roller that can handle all of those rolls quickly and concisely or not. Rolling so many perception tests will bog down a game, particularly since you're probably going to have to roll more than one for many marines.

The way I see it, one marine seeing him doesn't mean that all marines see him. The one who spots him can spend an action to say "Hey, over there!" and point or give more detailed directions, but that just means that the others know where to look, not that they can actually see him. They can either spend actions to keep looking until they see something or blind fire. Of course, it is far easier and faster for the marine who initially spotted him just to give the coordinates to the the team's mortar operator.

1 success just means that the character knows that something is there, not that the character knows what it is. In the case of marines spotting He-Man, that means that 1 success isn't enough for them to know that he is He-Man. They can't even be sure that he's human or just one guy. For all they know at this point he could be a pair of lesbian unicorns or an orphan girl scout selling cookies to raise money for spina bifida research. It isn't enough to justify actually shooting. The marine who saw him has to make more perception tests, successes of which stack with the original success, to be sure. This produces a delay between spotting and shooting.

If you don't have a good dice roller, the rules for team perception tests in SR3 say (the mean intelligence of the group) + (the number of people in the group). This means fewer dice rolled in total but it also means that everyone sees him all at once.
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Cantankerous
post May 25 2008, 04:31 PM
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The basis is a simple open test for the sneaker and the result as a target number for the sneaky (IMG:style_emoticons/default/smile.gif) . Say Stealthy Sam has a Stealth*5(Urban*7) and is going down a dark, foggy alley way trying to avoid being noticed by Diligent Corp. Guard (minimal light and light fog vs cyber low light vision), Stealthy is partially hidden during the movement. The open test resulted in a 6 (with an additional +10 for modifiers) and get a TN*16. Diligent has three dice for perception but manages to roll a 17. Success! But...

All that this means is that he realizes that "something is there"...somewhere out there. Now we do a simple opposed skill roll with maybe a small bonus to the suddenly suspicious guardsman of a few dice. 7 dice vs TN*4 against 3+2(5) dice Vs TN*4. He's still partially hidden in the dark and foggy alley way and this pushes Dilegent's TN up by +10 again, so his chances aren't good. Time and weather are always BIG factors for such a thing and should be. In the example Stealthy got two more success than Diligent so ol' D puts it down to tired eyes and goes on about his patrol.

Isshia
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kzt
post May 25 2008, 05:48 PM
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Assuming the plan is sane and the character is doing stealthy things I'd probably just have a single roll for the entire group once. Repeat as appropriate to the plot, which I'd argue that if the runner is lying totally still is about once an hour. If the character is using optics or other shiny stuff I'd give a check more often (unless they have taken pains to avoid reflections), and a reroll if the character aims a gun or does something else involving movement. It's HARD to see a man sized object at 500 meters, much less one that it trying to keep hidden.

If the security guys are using optics/electronics to methodically search I'd probably give each guy searching a roll, and more often, like one per 10 minutes.

This assumes the situation isn't silly, like someone sneaking in arctic snow without thermal dampening while the defender is searching with a thermal imager. That's like trying to stealthy follow someone while you are driving a fire truck with the lights and sirens on.
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Pendaric
post May 25 2008, 06:58 PM
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Rather than roll 90 dice I generally use probability averages.
With perhapes one roll at the stealth TN to represent outside chances.

Slaveish dedication to cannon can occassionaly break the system. Also just because there is thirty people/cameras/ anything else does not mean they are all looking at the right palce at the right time. So for realism would you now reduce the number of tests to represent the number of observes looking the right way?
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Hocus Pocus
post May 26 2008, 03:04 PM
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well, usually when I can tell is when I get the red bloches all over my body. That is when I'm spotted *yuck,hyuck*
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Shiloh
post May 29 2008, 11:51 AM
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QUOTE (Wounded Ronin @ May 24 2008, 08:35 PM) *
Let's say that a shadowrunner, is lying prone 500 meters away from a platoon of 30 UCAS marines and is observing them through binoculars. How do we handle the perception tests the marines get to notice him? Does each marine get to roll Perception against some high TN to have a chance to notice the shadowrunner?


Bear in mind also that a platoon of marines will not all be looking in He-Man's direction. Any given jarhead will have an assigned sector to watch while moving, and if they're stationary in a tactical situation, they will take up an all-round defense posture, so only some will be looking the right way.

QUOTE
Secondly, would the marines immediately know the shadowrunner is there and be able to open fire on him if they got a single success? If not, what would one success mean?


One success means they've seen *something*. It would take further observation to determine whether the target was one that should be engaged under current rules of engagement. And at 500m with an assault rifle, the Marine that saw would be foolish to open fire: all it would do would be alert the observer that they had been spotted. They should be using any vision aids available as a matter of course, even if it's a x10 optical sight on their weapon, so having a peer at the target might not give away anything. Of course, if the troops have been paniced for some reason, green recruits might start blazing away immediately. Better troops would wait for a fire/weapons-free from their officer or NCO before engaging an unknown target.

QUOTE
I'm not sure how satisfactory it would be in the circumstances described to have the shadowrunner observe the marines from 500 meters way for 3 seconds and then within those three seconds a few of the marines aimbot-spin to squeeze an aimed burst at him.


It wouldn't be satisfactory at all. (IMG:style_emoticons/default/smile.gif)

QUOTE
Thirdly, given that a combat turn is only 3 seconds, how many combat turns should pass before the marines who didn't notice the shadowrunner are allowed to open fire on him? Again, my concern would be the surreal situation where at 500 meters within the first 3 seconds a few marines are firing on the shadowrunner, and then 3-6 seconds later following a few "speak a word" actions all 30 marines are firing aimed bursts at the shadowrunner so again by probability he likely gets ripped to shreds. I'm not a military expert but or anything but it seems a bit strange that looking at a platoon through binoculars for 6 seconds would result in instant death.


Again, remember that the Marines will not all focus on the first perceived threat. It could be a decoy and they will cover all other avenues of approach while they are assessing the perceived threat. Maybe 1/3 of the platoon would even be pointed that way. 500m is, as I've said, beyond effective range for most assault rifles. The fire base would lay down suppressing fire on the area and a maneuver element would begin trying to flank the position. The observer should be able to drop back behind cover and bug out before the maneuver element got within effective range. This all takes time to organise and time to cross the ground. TNs should be in the double figures, so there's no guarantee of even one hit. It does depend on the observer being sensible enough to choose a position with hard cover to retreat behind when the bullets start to fly.

QUOTE
Since DSF knows all the rules, what is the "correct" way to handle perception tests in the situation described above?

It's not all about rules; remembering that the Marines are people with their own objectives (like taking cover while yelling "Sniper!!") and constraints ("Hey, Private. Nice shooting. This little girl got hit right between the eyes.") and limitations (not every grunt carries binoculars). The Marines are not a borg hivemind and aren't marching across a blank white plain.

Frankly, I'd be surprised if a prone observer at 500m was even spottable without assistance if they're using any sort of concealment at all. 500m is a long way, and a good sniper in a Ghillie Suit can shoot you from 30m and you won't know where they are.
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Cantankerous
post May 29 2008, 01:41 PM
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QUOTE (Shiloh @ May 29 2008, 01:51 PM) *
Bear in mind also that a platoon of marines will not all be looking in He-Man's direction. Any given jarhead will have an assigned sector to watch while moving, and if they're stationary in a tactical situation, they will take up an all-round defense posture, so only some will be looking the right way.



One success means they've seen *something*. It would take further observation to determine whether the target was one that should be engaged under current rules of engagement. And at 500m with an assault rifle, the Marine that saw would be foolish to open fire: all it would do would be alert the observer that they had been spotted. They should be using any vision aids available as a matter of course, even if it's a x10 optical sight on their weapon, so having a peer at the target might not give away anything. Of course, if the troops have been paniced for some reason, green recruits might start blazing away immediately. Better troops would wait for a fire/weapons-free from their officer or NCO before engaging an unknown target.



It wouldn't be satisfactory at all. (IMG:style_emoticons/default/smile.gif)



Again, remember that the Marines will not all focus on the first perceived threat. It could be a decoy and they will cover all other avenues of approach while they are assessing the perceived threat. Maybe 1/3 of the platoon would even be pointed that way. 500m is, as I've said, beyond effective range for most assault rifles. The fire base would lay down suppressing fire on the area and a maneuver element would begin trying to flank the position. The observer should be able to drop back behind cover and bug out before the maneuver element got within effective range. This all takes time to organise and time to cross the ground. TNs should be in the double figures, so there's no guarantee of even one hit. It does depend on the observer being sensible enough to choose a position with hard cover to retreat behind when the bullets start to fly.


It's not all about rules; remembering that the Marines are people with their own objectives (like taking cover while yelling "Sniper!!") and constraints ("Hey, Private. Nice shooting. This little girl got hit right between the eyes.") and limitations (not every grunt carries binoculars). The Marines are not a borg hivemind and aren't marching across a blank white plain.

Frankly, I'd be surprised if a prone observer at 500m was even spottable without assistance if they're using any sort of concealment at all. 500m is a long way, and a good sniper in a Ghillie Suit can shoot you from 30m and you won't know where they are.



From 500 meters, if there is anything but barren ground, you could easily miss a small bus.


BB
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Kagetenshi
post Jun 1 2008, 03:13 PM
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QUOTE (Wounded Ronin @ May 24 2008, 03:35 PM) *
Let's say that a shadowrunner, pictured here, is lying prone 500 meters away from a platoon of 30 UCAS marines and is observing them through binoculars. How do we handle the perception tests the marines get to notice him? Does each marine get to roll Perception against some high TN to have a chance to notice the shadowrunner? If so, even if we assume that all the marines have average intelligence, that would add up to 30 rolls of 3 dice, or 90 rolls alltogether. Even if the TN to spot the shadowrunner is around 15-20 it seems likely that the shadowrunner would be spotted, since there are so many rolls taking place. But I'm not sure if that's satisfactory or realistic because it means that the best defense against stealth is just to have many many people present since this adds up to more dice rolls.

Don't go with what "seems likely", do the math! TN 15, 90 dice, ~81% chance of success. TN 20, 90 dice, ~29%.

The standard Perception table doesn't really handle this kind of extreme situation well; depending on the situation, the TN could be about 20 or it could be meaningfully higher (at TN 25, say, we're looking at a ~6.7% chance of a single success). I'd also argue that modifiers like "distracted" and additional modifiers for there being, you know, a bunch of people between you and something you might see might affect a bunch of them.

QUOTE
Secondly, would the marines immediately know the shadowrunner is there and be able to open fire on him if they got a single success? If not, what would one success mean? They sense a disturbance in the force? How many successes would they need to be able to open fire? I'm not sure how satisfactory it would be in the circumstances described to have the shadowrunner observe the marines from 500 meters way for 3 seconds and then within those three seconds a few of the marines aimbot-spin to squeeze an aimed burst at him.

Per the Perception Test Table, a single success is "something is there". If the soldiers are not alert at all (safe area or simply overconfident/careless), that appears to map to "no action taken". If they're on guard, it probably maps to increased caution. At best it might permit some blindfire, IMO.

Two successes is knowledge that something is definitely there, with suspicion about the nature of the thing. In this kind of case, that sounds like enough of an idea to permit blindfire at the target, maybe more if you're ungenerous. Two successes on 90 dice at TNs: 15: ~50%, 20: ~4.8%, 25: ~0.23%

(Note that these estimates are overestimates, probably wildly so—to actually count for this, the same person has to get both successes (or all three, later on), which is a lot harder than just getting two between everyone. I'm too tired to do it properly, though.)

Three successes is stuff like "there's someone there", or maybe "there's someone there with awesome pects" (I'd normally put "a huge freakin' gun", but the example you give is lacking in that department so I went with the other thing that would be plainly visible at 500 meters). That sounds like we're getting into directed-fire territory. Three successes on 90 dice at TNs: 15: ~23%, 20: ~0.53%, 25: 0.0051%

QUOTE
Thirdly, given that a combat turn is only 3 seconds, how many combat turns should pass before the marines who didn't notice the shadowrunner are allowed to open fire on him? Again, my concern would be the surreal situation where at 500 meters within the first 3 seconds a few marines are firing on the shadowrunner, and then 3-6 seconds later following a few "speak a word" actions all 30 marines are firing aimed bursts at the shadowrunner so again by probability he likely gets ripped to shreds. I'm not a military expert but or anything but it seems a bit strange that looking at a platoon through binoculars for 6 seconds would result in instant death.

This is less authoritative, but my approach has generally been to give progressively smaller penalties to Perception and Intelligence rolls based around determining, either by perception or by deduction, exactly what the hell everyone around you is doing.

That's just my take.

The correct answer, of course, does not involve modifying a "die pool".

~J
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