Stealth: Difference between revisions

From GURPSworld Wiki
Jump to navigation Jump to search
 
(5 intermediate revisions by the same user not shown)
Line 1: Line 1:
''This house rule adds a quantifiable component to how close you can sneak up on someone.''
''This house rule adds a quantifiable component to how close you can sneak up on someone.''


'''DX/AVerage''' <br>
'''DX/Average''' <br>
<span style="color:fuchsia"> ''Defaults:  DX-5 or IQ-5'' </span>
<span style="color:fuchsia"> ''Defaults:  DX-5 or IQ-5'' </span>


Line 12: Line 12:


===Modifiers===
===Modifiers===
In some cases, it's not obvious if a modifier should be applied to the Stealth roll or the Perception roll.  It really doesn't matter in a Quick Contest; just be sure not to double dip.
In some cases, it's not obvious if a modifier should be applied to the Stealth roll or the Perception roll.  Whatever is decided, be sure not to double dip.


* a penalty equal to your encumbrance level
* a penalty equal to your encumbrance level
Line 28: Line 28:
=====Movement Modifiers=====
=====Movement Modifiers=====
* a penalty equal to your move-1 (i.e. no penalty if you're moving 1 yard/sec)
* a penalty equal to your move-1 (i.e. no penalty if you're moving 1 yard/sec)
* +5 if you're move is 0, and you're not active, i.e. you took a concentrate maneuver specifically to be stealthy
* +3 if you're move is 0, but you are still active, e.g. staying put but took a Ready maneuver
* +3 if you're move is 0, but you are active, e.g. staying put but readying a weapon or taking an aim maneuver
* +5 if you're move is 0, and you are effectively motionless and silent, i.e. staying put but took an aim maneuver
* +10 if you're move is 0, and you're completely hidden and not observing your foe, i.e. you're just plain hiding
* +10 if you're move is 0, and you're completely hidden and not observing your foe, i.e. you're just plain hiding



Latest revision as of 00:10, 16 December 2010

This house rule adds a quantifiable component to how close you can sneak up on someone.

DX/Average
Defaults: DX-5 or IQ-5

The rules of B222 still apply, except when the application of Stealth becomes a "Quick Contest between your Stealth and the sentinel's Perception" or to "stalk game" (which should be resolved as a Quick Contest vs. the animal's Perception). The penalty for moving more than 1 yard/sec while being Stealthy has also been modified.

Stealth vs Perception

The GM will use the result of the Quick Contest between Stealth and Perception and apply the results to the Size and Speed/Range Table [B550] to determine at what distance the stealthy person is seen and/or heard. Since the Stealthy person will know how good their roll is, they will have an informed opinion when they tell the GM how close and how quickly they intend to approach their quarry. If they chose a distance that is not too close, then they will not be detected; if they choose a distance that is too close, then they will be detected the moment they step into the range determined by the Size and Speed/Range Table [B550]. On a tie, the quarry has noticed something (heard a twig snap, caught movement out of the corner of their eye, etc.) and can react, but will not know the source of the disturbance.

After the Stealthy person makes a roll, they must move one or more hexes towards their intended target. Assuming they were not discovered, they can then request another Quick Contest (at no penalty for a repeated attempt) if they want to try to move even closer, or to quietly slink away. Thus, a Stealthy person could break up their approach into more than one Quick Contest if that is to their liking.

Modifiers

In some cases, it's not obvious if a modifier should be applied to the Stealth roll or the Perception roll. Whatever is decided, be sure not to double dip.

  • a penalty equal to your encumbrance level
  • -5 to fool those with Discriminatory Smell, usually animals (unless you are downwind of them)
  • (darkness penalties will affect perception rolls)
Environmental Modifiers
  • +10 they're inside an enclosed structure, e.g. they're on the other side of a closed door
  • +5 they can't possibly see you, e.g. their back is to you
  • +3 many hiding places, e.g. stalking game in a forest where tree trunks will hide you
  • -3 an area void of ambient noise, e.g. inside a empty building, no a/c, no fluorescent lights, isolated from outside street noise
  • -5 an area without "natural" hiding places, e.g. stalking someone down the hotel hallway
  • -10 a bare area with no shadows, e.g. a clearing in the woods or an empty room
Movement Modifiers
  • a penalty equal to your move-1 (i.e. no penalty if you're moving 1 yard/sec)
  • +3 if you're move is 0, but you are still active, e.g. staying put but took a Ready maneuver
  • +5 if you're move is 0, and you are effectively motionless and silent, i.e. staying put but took an aim maneuver
  • +10 if you're move is 0, and you're completely hidden and not observing your foe, i.e. you're just plain hiding

Example 1: Sentry Removal

Corporal Lee Linda wants to sneak all they way up to a guard who is guarding the door to an enemy safe-house. It is night; the guard and door are dimly illuminated but the rest of the surrounding area isn't. The guard is 5 yards from the corner of the building. Lee's Stealth is 13; the sentry's Perception is 11.

Lee informs the GM he wants to use Stealth to sneak up to the guard, so situational modifiers are assessed. Since Lee will approach from the side of the building, where the guard can not possibly see him, he'll be at a +5 until he rounds the corner. Once he rounds the corner, he'll be in a bare area, a -10 penalty; but it's dark, so the GM decides a net penalty of -5 is appropriate.

Lee sets out, rolling an 11, a success by 2. Assuming the sentry made his Perception roll exactly and ignoring situational modifiers, Lee would be detected when he got 1 yard from the guard: -2 on the Size and Speed/Range Table [B550]. Applying the -5 penalty after rounding the corner results in a failure by 3. +3 on the Size and Speed/Range Table [B550] means Lee would be detected 7 yards away. Lee thinks he can do better, so he informs the GM he'll move up to the corner of the building. Lee doesn't know this, but the guard also rolled an 11. Since Lee is at a +5 until he rounds the corner, he easily makes it to the corner of the building without being heard.

Having gotten to corner, Lee now rolls to proceed even closer. He'll be at -5 after he rounds the corner. Lee rolls a 9, succeeding by 4, adjusted to failing by 1: 3 yards on the Size and Speed/Range Table [B550]. Lee knows this in not close enough to attack with his Garrote, but he is committed to moving at least one yard closer. Lee informs the GM he'll move only one yard closer this turn. (He's hoping that if he's not detected this turn, he'll be able to All Out Attack him next turn with the element of surprise.) The sentry rolls an 8, succeeding by 3; so Lee actually lost the Quick Contest by 4, resulting in detection at 10 yards. The GM informs Lee that as soon as he rounds the corner, the guard looks over and sees him. (The element of surprise diminished, Lee will be forced to choose between attempting to take him out quietly in hand-to-hand combat, or readying his M4.)

Example 2: Bow Hunting

Shung Jiao and Shung Li are out bow hunting. Jiao would like to get as close as possible before taking his shot. Li is tracking the wild boar and they are both moving stealthily as the trail seems fresh. They are in the woods and the boar is not downwind of them, so the GM gives them a +3 bonus situational modifier. Shung Jiao's Stealth is 10, Li's is 12; Shung Jiao rolls a 9, Le rolls an 11; they both make their rolls by 1, by 4 with the modifier. They would like to get within 15 yards of the boar. (Shung Jiao's bow skill is 12. Acc 1 with 3 seconds of aiming can increase this to 15. The range penalty at 15 yards is -5.) If they lose the Quick Contest by 4 or less, they're okay. (5 is not okay because then they'd be detected at 15 yards.) They decide this roll is good enough that they've probably not even lost the Quick Contest and commit to approach to 5 yards. Unknown to them, the boar with Perception 12 rolled a 10, succeeding by 2. They won their Quick Contest by 2. The GM informs then they're 5 yards away from a wild boar that is ignoring them. Shung Jiao can now set up his shot. If Shung Jiao decides he wants to move even closer (maybe Shung Jiao decides he wants to staff hunt instead) they will both have to engage in another Quick Contest. Of course, Li will be at +10 since he will choose not to approach with Shung Jiao.

See Also

2d Damage optional | Combat Maneuvers | Detect Lies | Interrogation | Meditation | Tactics

STA main page