Difference between revisions of "Backstab"

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(Mechanism: reworded thing about the Spy-cicle)
(Undo edit by Toomai This explanation is written in a way that the average person can somewhat easily understand it. The changes made make it more "technically" accurate, but less understandable for regular players)
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<div style="float: right; width: 20%;">{{Kill notice|extend=yes|invert=yes|killer=Spy|victim=Heavy Weapons Guy|weapon=backstab|width=100%}}</div>
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<div style="float: right; width: 30%;">{{Kill notice|extend=yes|invert=yes|killer=Spy|victim=Heavy Weapons Guy|weapon=backstab|width=100%}}</div>
[[Image:Spybackstab.png|175px|right|Surprise.]]
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[[File:Spybackstab.png|175px|right|Surprise.]]
{{Quotation|'''The Spy'''|'''Surprise.'''|sound=Spy_specialcompleted12.wav}}
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{{Quotation|'''The Spy'''|'''Surprise.'''|sound=Spy specialcompleted12.wav}}
  
A '''backstab''' is a context-sensitive attack that a [[Spy]] can perform with any of his [[Weapons#spymelee|melee weapons]]. When a Spy uses any one of his knives to hit an enemy from behind, a successful backstab is performed, resulting in an instant kill in almost all cases.  
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A '''backstab''' is a context-sensitive attack that a [[Spy]] can perform with any of his [[Weapons#spymelee|melee weapons]]. When a Spy uses any one of his knives to hit an enemy from behind, a successful backstab is performed, resulting in an instant kill in almost all cases. Backstabs deal no damage to enemies with invulnerability effects, such as those under the effects of a standard [[ÜberCharge]], though the Spy still raises his knife and performs the usual backstab animation.
  
 
== Mechanism ==
 
== Mechanism ==
A Spy may backstab an enemy as long as the enemy is close within standard [[melee]] attack range, and the Spy is within a 180° range behind the enemy. Backstabs deal damage equal to 200% of the target's current health and always deal [[critical hits]] (increasing the damage to 600% of the target's current health), unless otherwise prevented by a [[Battalion's Backup]]. However, a Battalion's Backup will not cause a damage reduction. Due to the mechanics of the Spy's melees, unlike most melee weapons, backstabs connect instantly upon activation; there is no delay between the moment the player attacks and the moment the backstab is executed. To indicate that a Spy is within the required range to perform a backstab, he will raise his knife then turn it downward, primed for a kill. The knife will remain in this position until the target is no longer in reach, or the Spy attempts a backstab by attacking. The knife also turns downward if positioned behind a disguised or [[Cloak]]ed enemy Spy. When the knife is pointed downward, the Spy simply needs to attack for an instant kill to occur.  
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[[File:Backstab max backstab angle.png|right|thumb|The maximum angle for a backstab]]
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[[File:Backstab max considered behind.png|right|thumb|The maximum of what the game considers being behind an enemy for backstabs]]
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To indicate that a Spy is within the required range and angle to perform a backstab, he raises his knife and turns it downward, primed for a kill. The knife remains in this position until the target is no longer in reach, which is 40 [[Hammer unit]]s to the target's back, or the Spy attempts a backstab by attacking. The knife turns downward even if positioned behind a [[cloak]]ed or [[disguise]]d enemy Spy. As the Spy's [[melee]] weapons do not have a delay between the swing being initiated and the damage being dealt, as long as the knife is pointed downward, the Spy simply needs to attack for an instant kill to occur.
  
A backstab can be performed while the Spy has a [[disguise]] active, although the disguise will be removed upon attacking, regardless of whether or not the attack connects with the enemy. A backstab cannot kill a [[Scout]] made invulnerable with [[Bonk! Atomic Punch]], a player who is under the effects of an [[ÜberCharge]], or a Spy with the [[Dead Ringer]] active who has more than 3 health points. The [[Razorback]], an unlockable secondary weapon usable by the [[Sniper]] class, blocks a single backstab attempt. The Razorback also causes a temporary (about 2 seconds) inability to attack, Cloak, or switch weapons for the offending Spy. Thus, the Razorback makes Snipers less prone to backstabs and encourages Spies to use their [[Spy#Secondary|secondary weapon]] instead.
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Should a Spy perform a melee attack that connects with an enemy while he is behind said enemy, a backstab occurs. Backstabs deal damage equal to 200% of the target's current health and are always [[Critical hits]], resulting in a total damage of six times the victim's current health; while the critical damage can be negated, this does not stop the stab from being lethal unless the target has significant additional protection.
  
Backstabbing with [[Your Eternal Reward]] or the [[Wanga Prick]] causes silent death. Your victims will not scream, their body will vanish, and no killfeed notification is given to the victim's teammates. The attacking Spy will disguise as the fallen enemy almost instantly.
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A backstab triggers as long as the Spy is behind an enemy (ignoring verticality, meaning he can backstab if above or below an enemy) and the enemy is facing roughly away from him. The Spy can backstab in an approximately 180 degree radius around the enemy's back, which means a Spy facing an enemy's side is still capable of backstabbing that enemy. The game considers the Spy to be facing the same direction as the enemy as long as the crosshairs of both these players are pointing in directions within 107.4 degrees from each other.
  
Backstabbing with the [[Conniver's Kunai]] will take the victim's remaining [[health]] and give it to the Spy, up to a maximum of 180. This is offset by a lowered base health.
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More precisely, the game checks for several [[w:Dot product|dot products]] (a formula to check if two things are facing the same direction. The outcome is a number between 1 and -1, with 1 meaning they face the same direction and -1 meaning they face each other) before allowing a backstab. The game checks if:
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* The dot product between a vector from the Spy's position to the enemy's position and the direction the enemy is facing is larger than 0 — this means that the Spy needs to be behind the enemy.
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* The dot product between the vector from the Spy's position to the enemy's position and the direction the Spy is facing is larger than 0.5 — this means that the Spy's crosshair cannot be aimed more than ~54-64 degrees <!--From in-game testing using cl_showpos 1, it shows this can range from 54 degrees to 64 --> away from the victim's back.
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* The dot product between the direction the enemy's crosshair is facing and the direction the Spy's crosshair is facing is larger than -0.3 — this means that the Spy and enemy cannot be facing each other.<ref>game\shared\tf\tf_weapon_knife.cpp:L395-430</ref>
  
Backstabbing with the [[Big Earner]] will fill the Spy's Cloak meter by 30%, regardless of which cloaking device is equipped.
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If all of these conditions are met, the game allows for a backstab.
  
Backstabbing with the [[Spy-cicle]], like Your Eternal Reward, prevents your victims from screaming and does not alert the enemy team's killfeed. However, instead of cloaking the corpse, they will turn into an ice statue, which also creates a loud freezing/cracking noise. This is a clear sign that there is a Spy in the area, and other enemies can use this to track you down.
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Like normal melee attacks, backstabs can be performed while disguised, though the Spy proceeds to lose his disguise whether the attack connects or not. Backstabs are nothing more than pure damage, and so cannot injure or kill invulnerable players. [[Buildings]] and Halloween bosses cannot be backstabbed.
  
Backstabbing a giant in [[Mann vs. Machine (game mode)|Mann vs. Machine]] will deal up to 750 base damage, but this is reduced to 25% of that (188) by default; each armor penetration upgrade restores 25% of the base damage, up to 125% of the base (938).
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[[Robots]] in [[Mann vs. Machine]] can be backstabbed just as normal players. In addition to this, if a robot is [[Sapper|sapped]], it can be backstabbed from any direction, not just from behind. However, giant robots operate much differently. Backstabbing a giant has a base damage of 750, but this is reduced to 25% of that (188) by default; each armor penetration [[Upgrade Station|upgrade]] restores 25% of the base damage, up to 125% of the base (938). Spies must therefore upgrade their knife in order to have a chance at taking out giant robots.
  
== Backstabbing techniques ==
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In [[Versus Saxton Hale]], backstabs deal a fraction of the overall damage to Saxton Hale and causes the Spy to flinch for 2.0s.
* '''Stab-and-Sap''': Stab a ([[turtling]]) [[Engineer]], before switching to your [[Sapper]] and sapping the Engineer’s [[Sentry Gun]]; this must be done fast enough that the Sentry Gun doesn't have time to turn around and kill you. An experienced Spy may track the Sentry Gun's turning direction and move against it after he stabs (as it will follow him, this will buy him more time). Using [[Your Eternal Reward]] can be useful in this approach, as you instantly [[disguise]] upon a successful backstab, preventing the Sentry Gun from detecting you and retaliating; a Spy without a prior disguise must rely on cover to avoid the Sentry Gun's attention, as the Sentry will not be fooled by your instant disguise once it has already begun firing. This tactic is slightly easier on Engineers using the [[Wrangler]], because the Sentry Gun is disabled for one second after the Engineer's death.
 
  
* '''Sap-and-stab''': Sap an Engineer's unattended [[building]] as bait, hide, then stab him when he returns to remove the Sapper.
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Various weapons affect backstabs in some fashion:
  
*'''Overhead stab''' or '''Stairstab''': Stand at the top of a set of stairs, ramp, prop, or any slight elevation (Teleporters work fine, but are harder), facing down at an enemy approaching you. Run forward and crouch-jump, releasing forward while turning in mid-air to stab them in the back. This technique can be difficult to master, but it is also difficult to protect against, as the enemy has to turn almost completely around to avoid it. The amount of time spent crouching is critical for this trick; the stab will not register without crouching.
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* Backstabbing with [[Your Eternal Reward]] or the [[Wanga Prick]] causes silent death. The victim does not scream, their body vanishes, and no killfeed notification is given to the victim's teammates. The attacking Spy disguises as the fallen enemy almost instantly.
** More experienced players will either avoid climbing, moving towards you, or even backing out of range when they see a Spy at the top of the stairs or ramp. Instead of advertising your intent, you can perform the stab without having to wait at the top. While retreating up the stairs, jump up and hold back. Most players will continue to run forward, passing underneath you. Backstab them as you land.
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* Backstabbing with the [[Conniver's Kunai]] takes the victim's remaining [[health]] (or 75 health if the victim has less than 75 health) and gives it to the Spy, up to a maximum of 210. This is offset by a lowered base health.
*** There are multiple ways to counter this, and both are for advanced Spies. One is to perform a '''Blind stab''' where you duck out of sight before making the stab, which could be a Drop stab. Strafing is sometimes necessary, but the difficult part is predicting your target's actions. Another way is to perform a "Reverse" Stairstab, where you run forward to just large enough of a height advantage, crouch jump backwards and go forward to stop your jump just above your target's head before backstabbing them. Both generally work since even top players won't suspect you.
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* Backstabbing with the [[Big Earner]] fills the Spy's Cloak meter by 30%, regardless of which cloaking device is equipped. A backstab with this weapon also gives the Spy a three-second speed boost.
** Some Spies may prefer to execute this stab by landing on top of the enemy's head instead of directly behind them. To do this, you will have to stop yourself in the air to avoid sliding off the player's head by using the opposite strafe key than the direction you are going. You can then stab while crouched on top of the other players head. The benefits of doing it this way is that it can be executed a lot faster, so the other player has less time to react, you have more time to stab, and even if the player turns completely around, you can still use your strafe keys to position yourself into their backstab hitbox and get the stab.
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* Backstabbing with the [[Spy-cicle]] turns enemy [[ragdoll]]s into an ice statue, which also creates a loud freezing/cracking noise, in addition to the usual victim screams.
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* Attempting to backstab a [[Sniper]] wearing the [[Razorback]] results in the backstab being blocked, in addition to preventing the Spy from attacking, cloaking, or switching weapons for 2 seconds afterward. Thus, the Razorback makes Snipers less prone to backstabs and encourages Spies to use their {{botignore|[[Spy#Secondary|selected revolver]]}} instead.
  
*'''Quickstab''': While an enemy is running towards you, let them run past you before spinning and stabbing their retreating back. This is one of the only reliable methods of backstabbing [[Scout]]s or any enemy that buys your disguise.
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== Backstabbing techniques ==
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* '''Stab-and-Sap''': Stab a ([[turtling]]) [[Engineer]], before switching to your [[Sapper]] and sapping the Engineer’s [[Sentry Gun]]; this must be done fast enough that the Sentry Gun does not have time to turn around and kill you. An experienced Spy may track the Sentry Gun's turning direction and move against it after he stabs (as it follows him, this buys him more time), this set of movement is also known as circle-strafing. Using [[Your Eternal Reward]] can make the approach easier, as you instantly [[disguise]] upon a successful backstab, preventing the Sentry Gun from detecting you and retaliating; a Spy without a prior disguise must rely on cover to avoid the Sentry Gun's attention, as the Sentry is not fooled by your instant disguise once it has already begun firing. This tactic is slightly easier on Engineers using the [[Wrangler]], because the Sentry Gun is disabled for three seconds after the Engineer's death.
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* '''Sap-and-Stab''': Sap an Engineer's unattended [[Buildings|building]] as bait, hide, then stab him when he returns to remove the Sapper. Alternatively, sap a turtling Engineer's building, then switch to the Knife to backstab him as a less effective variant of the stab-and-sap technique.
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*'''The Topstab''': Sometimes paranoid Engineers place their Sentry Gun and [[Dispenser]] in a fashion that allows the Engineer to have his back to a corner, making him seemingly protected from backstabs. It is possible to kill him by climbing over his Dispenser or Sentry Gun and jumping onto his head. Face the same direction as the Engineer and crouch until you get the "Knife-raised" animation, allowing you to score a backstab.
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*'''Quickstab''': While an unaware enemy is running towards you, let them run past you before spinning and stabbing their retreating back. This is one of the only reliable methods of backstabbing [[Scout]]s or any enemy that believes your disguise.
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*'''Sidestab''': As the name suggests, a side stab is accomplished by stabbing the back of an enemy from the side. Because of how the characters' hitboxes are positioned, this is easier from the enemy's right than their left.
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*'''Dropstab''': This involves the Spy waiting at a high spot, and jumping down on an unsuspecting enemy's head while holding crouch, and killing the enemy in a similar fashion as the Topstab.
  
*'''The Corner Stab''': This is an advanced Spy technique. The technique involves luring an enemy to a corner, then immediately backing out and stabbing the enemy as he turns in the way you did. Note that this can sometimes only work once or twice on an enemy, and is best used on pursuits with [[Scout]]s or [[Pyro]]s.
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=== Trickstabs ===
 
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Trickstabs are special techniques for backstabs that involve specific movements, such as jumping over an enemy player or pretending to move one way then moving the other way. The following are most of the trickstabs used by Spies:
*'''The Topstab''': Sometimes Engineers will place their Sentry Gun and [[Dispenser]] in a fashion that allows the Engineer to have his back to a corner, making him seemingly protected from backstabs. It is possible to jump on this Engineer's head via climbing from his Dispenser or Sentry Gun while positioning yourself over the Engineer (facing the same direction as him) around his back until you get the "Knife-raised" animation, allowing you to score a backstab with a click.
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*'''Matador''': Usually most effective against support classes attempting to engage in melee combat (such as Engineers or Medics), this involves tricking an enemy into turning towards in your direction by pretending to run around them one way, then quickly moving back, strafing into backstabbing range as they turn toward, and backstabbing your pursuer.
 
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*'''Stairstab''': This technique involves running up an elevated surface and jumping over your pursuer's head, landing behind or on top of them and scoring a backstab. This is less effective against more experienced players, as it is often highly predictable and can be easily countered. There are several, lesser known, variations. This can also be done on small elevated surfaces too, such as [[Teleporters]].
*'''The Leap Stab ''(or Drop Stab or Eagle Stab)''''': This is similar to overhead stabs, but instead it focuses on striking enemies from a significant height (usually from ground above the opponent - bridges, roofs, ledges) and is best used with either the [[Cloak and Dagger]] or [[Dead Ringer]]. Cloak on a bridge/high place (or hide if you're using Dead Ringer) and as the enemy passes beneath the spot, jump after them and stab them in the back. Doing the stab itself is easier with the Cloak and Dagger, but getting away is easier with the Dead Ringer (especially against multiple opponents). The enemy will have no idea where you came from, as they usually do not check the skies.  
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*'''Cornerstabs''': This takes advantage of the map such that the enemy pursuing the Spy would turn a corner (which does not necessarily need to be blind), and exposing their side to the Spy, in a similar fashion to the Matador stab.
** Attempting to leap stab the same opponent at the exact same spot twice could be a bad idea (doing it again elsewhere is more secure, though he might be paranoid) - this tactic may be best used while the enemy is distracted, as they will not notice you jumping on them.
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*'''Circlestrafe stab''': A highly advanced yet unreliable type of trickstab that is designed to counter strafing enemies who do not turn enough to fall for a matador, or enemies who backpedal. There are currently four known types.
 
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# For enemies who are holding W and a strafe key while strafing into the Spy, the Spy moves into and intersects the path of the pursuing enemy.
*'''The Matador stab''': This is an advanced Spy technique and a difficult one to master. To perform it, you must be facing a single enemy, who is facing you. Either run towards him or let him approach you, then, just before he is in melee reach, strafe in one direction (left or right) for a split second, before quickly changing direction and strafing to the opposite side. This will reveal the enemy's back for a very short moment as he follows your first strafe, and you should stab him promptly during this brief gap. This is useful for those players that dismiss Spies and try to melee them, such as some Scout players. Should this technique fail, and you miss the stab, you will be extremely vulnerable in close-range and will almost certainly die, but when performed correctly, this technique enables you to stab an enemy in a potentially fatal situation. Great for Dead Ringer Spies. Not recommended to try this on Pyros; the technique might still work, but unless the Pyro wants to melee you, you will probably be set alight and dealt a fair share of damage. Once you get more confident with this stab, it becomes perfect for Pyros who try and come at you with their Axtinguisher. One quick side-step and you should have them.
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# For slow, backpedaling enemies (e.g. Soldiers and Demomen), the Spy backpedals along the enemy's side and attempts a sidestab.
 
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# For enemies who are strafing between two points, such as a Scout aiming towards a Spy, the Spy strafes to the opposite direction of where the enemy is strafing, and relying on the enemy to strafe back into them (e.g. A Scout moves towards the Spy's left side, the Spy moves towards his right side, and eventually the Scout strafes back into the Spy while attempting to strafe-aim).
*'''The Understab''': This backstabbing technique involves hitting an enemy with the knife in a second that you are under them. It is typically used on pursuers of the Spy when the victim is falling from a height and the Spy can abuse this to strafe under the victim using the horizontal arrow keys and stab them for the brief moment the victim is exposed. The technique sometimes involves standing still before strafing to confuse an enemy and thereby generally forcing them to move in a predictible pattern and allow for an opportunity to get under the victim as they fall. The Understab is also known for being a risky counter to the above mentioned Overhead/Stairstab as the player is turning. The understab can also be used on unaware enemies in areas such as spawns where players drop from a height or other common paths that have drops that the Spy can use.
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# For enemies who are attempting to strafe behind the Spy, the Spy matches the enemy's movement by holding S and a strafe key, and attempts a sidestab while backpedaling.
 
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*'''Surfstab''': An extremely situational stab where the Spy surfs explosive damage or enemy airblasts, and kills the/another enemy while landing on them, similar to a Dropstab.
*'''The Strafe-and-Snap''': This is a highly advanced backstab technique. This stab is similar to a matador stab, but instead of strafing back to the player, you strafe away. To execute this stab, run at the enemy, but just before you reach them, release the forward key, then as fast as you can, snap your view towards the player at the same time as strafing the opposite direction while clicking. This stab takes a lot of practice to master, but once you get it down, it can prove extremely useful for tight situations.
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*'''Airstab''': Also an extremely situational stab where both the Spy and the enemy get near each other while airborne, the stab is applied specially at high speeds, similar to a sidestab, the Spy quickly flicks his aim to the enemy's back and then stabs. To prevent the loss of your momentum while airborne due to bumping, strafe around the enemy and then stab.
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*'''Dropstab''': Done when falling from a height and backstabbing an enemy before or right when the Spy lands.<!--
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Please do not add more trickstabs, as they are all covered here -->
  
 
== Issues ==
 
== Issues ==
{{see also|Lag compensation}}{{anchor|Backstab Issues}}
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{{See also|Lag compensation}}{{anchor|Backstab Issues}}
 
 
* Due to an in-game glitch, a stab that has appeared to have occurred from the front can sometimes be rendered as a backstab. Known more commonly as a ''facestab'', these kills are now mostly the result of lag compensation by the game engine itself. Prior to many game [[patches]], facestabs were more common due to bugs in the way the game detects a backstab. Facestabs take two forms: the "valid" stab and the "true" facestab. Most of what the recipient sees as a facestab is usually either a cornerstab or a sidestab, where on the Spy's screen, he sees it as attacking the target's back, but due to lag, the target sees the Spy attacking from the front. A valid facestab works as intended by the developers, making correct use of lag compensation. In a true facestab, the Spy appears to be attacking an enemy from the front on both players' screens, but lag compensation results in it being registered as a backstab. This is considered a bug.
 
  
* Another community-coined term is the ''failstab'', which refers to a backstab which should have succeeded but instead did only normal Knife damage, despite the backstab animation playing fully and the Knife connecting. These stabs are almost always linked to the latency conditions between the server and the player.
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* Due to a [[Glitches|glitch]] in the game, a stab that has appeared to have occurred from the front can sometimes be rendered as a backstab. Known more commonly as a ''facestab'', these kills are now mostly the result of lag compensation by the game engine itself. Prior to many game [[patches]], facestabs were more common due to bugs in the way the game detects a backstab. Facestabs take two forms: the "valid" stab and the "true" facestab. Most of what the recipient sees as a facestab is usually either a cornerstab or a sidestab, where on the Spy's screen, he sees it as attacking the target's back, but due to lag, the target sees the Spy attacking from the front. A valid facestab works as intended by the developers, making correct use of lag compensation. In a true facestab, the Spy appears to be attacking an enemy from the front on both players' screens, but lag compensation results in it being registered as a backstab. This is considered a bug.
 
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* Another community-coined term is the ''failstab'', which refers to a backstab which should have succeeded, but instead did only normal Knife damage, despite the backstab animation playing fully and the Knife connecting. These stabs are almost always linked to the latency conditions between the server and the player. A similar variant is a stab that plays the animation and the sound effect, but does no actual damage.
* Rarely, during taunts, the player's 'back' changes position; it becomes directly behind the player's 3rd-person camera, which means that players can avoid backstabs by moving the camera away from the Spy. This generally occurs by accident; for example, when you position the camera in front of you to watch the taunt yourself, making your back into your front. Facestabs can also rarely occur this way.
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* Rarely, during taunts, the player's 'back' changes position; it becomes directly behind the player's 3rd-person camera, which means that players can avoid backstabs by moving the camera away from the Spy. This generally occurs by accident; for example, when a player positions the camera in front of them to watch the taunt themselves, making their back into their front. Facestabs can also rarely occur this way.
 
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* The angle required for a backstab is based on the direction the victim is looking; however, all players have models whose normal stance has their backs rotated to the left slightly, due to the way they carry their respective weapons (this is most prominent with Heavies). This means that at certain angles the player appears to be stabbing their target in the back, when in fact the player is not inside the 180 degree angle for backstabs. Equally, there are valid backstab positions which appear to have the player stabbing slightly into the front of their victim. These hit-box positions can be determined by the shoulders of the character models.
* The angle required for a backstab is based on the direction the victim is looking; however, all players have models whose normal stance has their backs rotated to the left slightly, due to the way they carry their respective weapons (this is most prominent with Heavies). This means that at certain angles you appear to be stabbing your target in the back, when in fact you are not inside the 180 degree angle for backstabs. Equally, there are valid backstab positions which appear to have you stabbing slightly into the front of your victim. These hit-box positions can be determined by the shoulders of the character models.
 
  
 
== Related achievements ==
 
== Related achievements ==
 
=== {{class link|Soldier}} ===
 
=== {{class link|Soldier}} ===
 
{{Achievement table
 
{{Achievement table
| {{Show achievement|Soldier|War Crime Spybunal}}
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| 1 = {{Show achievement|Soldier|War Crime Spybunal}}
 
}}
 
}}
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=== {{class link|Sniper}} ===
 
=== {{class link|Sniper}} ===
Line 68: Line 79:
 
| 2 = {{Show achievement|Sniper|Consolation Prize}}
 
| 2 = {{Show achievement|Sniper|Consolation Prize}}
 
}}
 
}}
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=== {{class link|Spy}}===
 
=== {{class link|Spy}}===
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== Update history ==
 
== Update history ==
{{update history|
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{{Update history | '''{{Patch name|10|25|2007}}'''
'''{{Patch name|10|25|2007}}'''
 
 
* Fixed a Spy backstab exploit where you could stab a player who was not facing away from you.
 
* Fixed a Spy backstab exploit where you could stab a player who was not facing away from you.
  
Line 124: Line 135:
  
 
'''{{Patch name|10|18|2011}}'''
 
'''{{Patch name|10|18|2011}}'''
* Fixed a glitch where the Spy would take fall damage after backstabbing someone while standing on top of him.  
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* Fixed a glitch where the Spy would take fall damage after backstabbing someone while standing on top of him.
}}
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'''{{Patch name|10|30|2014}}'''
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* Fixed the knife not playing its backstab animation when Crits are disabled.}}
  
 
== Bugs ==
 
== Bugs ==
 
* When a player for the opposing team is standing on top of the Spy, the Spy can always perform a successful backstab regardless as to whether or not the Spy's aim falls within the regular backstab radius.
 
* When a player for the opposing team is standing on top of the Spy, the Spy can always perform a successful backstab regardless as to whether or not the Spy's aim falls within the regular backstab radius.
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* Occasionally, when swiping at an enemy, the Spy does the backstab animation, even if it was not a backstab.
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* Occasionally, a Spy takes fall damage after backstabbing someone while standing on top of the victim, even though this was supposedly fixed in the {{Patch name|10|18|2011}}.
  
 
== Trivia ==
 
== Trivia ==
*Originally, the Spy's backstab animation was just over a second long and manifested as the current animation, but was slowed down. This was changed to the current, sped up version used today in the interests of balance. Before this change, skilled Spies would "quick-stab". This involved staying out of backstab range of the victim, and then swinging the Knife just before entering backstab range, thereby bypassing the backstab animation but still rewarding an instant kill.
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* Originally, the Spy's backstab animation was just over a second long and manifested as the current animation, but was slowed down. This was changed to the current, sped up version used today in the interests of balance. Before this change, skilled Spies would "quick-stab". This involved staying out of backstab range of the victim, and then swinging the Knife just before entering backstab range, thereby bypassing the backstab animation, but still rewarding an instant kill.
*Killing a player with a backstab will sometimes cause a special backstab death animation. This animation has a 25% chance of occurring, and varies from class to class. The [[Sniper]] performs this animation and sound during [[Meet the Spy]].
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* The Sniper's unique backstab death animation was first seen in [[Trailer 2]] before any backstab animations were integrated into the game.
**The Sniper's backstab animation was first seen in [[Trailer 2]] before any backstab animations were integrated into the game.
 
*Despite dealing no damage, backstabbing an enemy who cannot be killed (Scout under the effects of [[Bonk! Atomic Punch]], [[Übercharge]]d enemies or Spies, cloaked with [[Dead Ringer]]) deals a great amount of knockback that can easily be used to push the enemy into [[Environmental death|environmental hazards]], such as off the side of [[DeGroot Keep]], causing them to die while being invincible.
 
*When the server has Random Crits turned off "tf_weapon_criticals 0", the backstabbing animation is removed, resulting in only a swing instead of a stab while dealing only 200% of the enemy's health instead of the usual 600% with Random Crits turned on.
 
  
 
== External links ==
 
== External links ==
*[http://technofovea.com/blog/archives/278 TF2 Backstab mechanics]
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* [https://technofovea.com/blog/archives/278 TF2 Backstab mechanics]
*[http://www.youtube.com/watch?v=DO1hbjr-QGM Video explaining how lag compensation affects backstabs]
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* [https://www.youtube.com/watch?v=DO1hbjr-QGM Video explaining how lag compensation affects backstabs]
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== References ==
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[[Category:Gameplay]]
 
[[Category:Spy]]
 
[[Category:Spy]]
 
[[Category:Strategy]]
 
[[Category:Strategy]]
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Latest revision as of 23:56, 7 October 2024

Spy 
Killicon backstab.png
 Heavy Weapons Guy
Surprise.
Surprise.
The Spy

A backstab is a context-sensitive attack that a Spy can perform with any of his melee weapons. When a Spy uses any one of his knives to hit an enemy from behind, a successful backstab is performed, resulting in an instant kill in almost all cases. Backstabs deal no damage to enemies with invulnerability effects, such as those under the effects of a standard ÜberCharge, though the Spy still raises his knife and performs the usual backstab animation.

Mechanism

The maximum angle for a backstab
The maximum of what the game considers being behind an enemy for backstabs

To indicate that a Spy is within the required range and angle to perform a backstab, he raises his knife and turns it downward, primed for a kill. The knife remains in this position until the target is no longer in reach, which is 40 Hammer units to the target's back, or the Spy attempts a backstab by attacking. The knife turns downward even if positioned behind a cloaked or disguised enemy Spy. As the Spy's melee weapons do not have a delay between the swing being initiated and the damage being dealt, as long as the knife is pointed downward, the Spy simply needs to attack for an instant kill to occur.

Should a Spy perform a melee attack that connects with an enemy while he is behind said enemy, a backstab occurs. Backstabs deal damage equal to 200% of the target's current health and are always Critical hits, resulting in a total damage of six times the victim's current health; while the critical damage can be negated, this does not stop the stab from being lethal unless the target has significant additional protection.

A backstab triggers as long as the Spy is behind an enemy (ignoring verticality, meaning he can backstab if above or below an enemy) and the enemy is facing roughly away from him. The Spy can backstab in an approximately 180 degree radius around the enemy's back, which means a Spy facing an enemy's side is still capable of backstabbing that enemy. The game considers the Spy to be facing the same direction as the enemy as long as the crosshairs of both these players are pointing in directions within 107.4 degrees from each other.

More precisely, the game checks for several dot products (a formula to check if two things are facing the same direction. The outcome is a number between 1 and -1, with 1 meaning they face the same direction and -1 meaning they face each other) before allowing a backstab. The game checks if:

  • The dot product between a vector from the Spy's position to the enemy's position and the direction the enemy is facing is larger than 0 — this means that the Spy needs to be behind the enemy.
  • The dot product between the vector from the Spy's position to the enemy's position and the direction the Spy is facing is larger than 0.5 — this means that the Spy's crosshair cannot be aimed more than ~54-64 degrees away from the victim's back.
  • The dot product between the direction the enemy's crosshair is facing and the direction the Spy's crosshair is facing is larger than -0.3 — this means that the Spy and enemy cannot be facing each other.[1]

If all of these conditions are met, the game allows for a backstab.

Like normal melee attacks, backstabs can be performed while disguised, though the Spy proceeds to lose his disguise whether the attack connects or not. Backstabs are nothing more than pure damage, and so cannot injure or kill invulnerable players. Buildings and Halloween bosses cannot be backstabbed.

Robots in Mann vs. Machine can be backstabbed just as normal players. In addition to this, if a robot is sapped, it can be backstabbed from any direction, not just from behind. However, giant robots operate much differently. Backstabbing a giant has a base damage of 750, but this is reduced to 25% of that (188) by default; each armor penetration upgrade restores 25% of the base damage, up to 125% of the base (938). Spies must therefore upgrade their knife in order to have a chance at taking out giant robots.

In Versus Saxton Hale, backstabs deal a fraction of the overall damage to Saxton Hale and causes the Spy to flinch for 2.0s.

Various weapons affect backstabs in some fashion:

  • Backstabbing with Your Eternal Reward or the Wanga Prick causes silent death. The victim does not scream, their body vanishes, and no killfeed notification is given to the victim's teammates. The attacking Spy disguises as the fallen enemy almost instantly.
  • Backstabbing with the Conniver's Kunai takes the victim's remaining health (or 75 health if the victim has less than 75 health) and gives it to the Spy, up to a maximum of 210. This is offset by a lowered base health.
  • Backstabbing with the Big Earner fills the Spy's Cloak meter by 30%, regardless of which cloaking device is equipped. A backstab with this weapon also gives the Spy a three-second speed boost.
  • Backstabbing with the Spy-cicle turns enemy ragdolls into an ice statue, which also creates a loud freezing/cracking noise, in addition to the usual victim screams.
  • Attempting to backstab a Sniper wearing the Razorback results in the backstab being blocked, in addition to preventing the Spy from attacking, cloaking, or switching weapons for 2 seconds afterward. Thus, the Razorback makes Snipers less prone to backstabs and encourages Spies to use their selected revolver instead.

Backstabbing techniques

  • Stab-and-Sap: Stab a (turtling) Engineer, before switching to your Sapper and sapping the Engineer’s Sentry Gun; this must be done fast enough that the Sentry Gun does not have time to turn around and kill you. An experienced Spy may track the Sentry Gun's turning direction and move against it after he stabs (as it follows him, this buys him more time), this set of movement is also known as circle-strafing. Using Your Eternal Reward can make the approach easier, as you instantly disguise upon a successful backstab, preventing the Sentry Gun from detecting you and retaliating; a Spy without a prior disguise must rely on cover to avoid the Sentry Gun's attention, as the Sentry is not fooled by your instant disguise once it has already begun firing. This tactic is slightly easier on Engineers using the Wrangler, because the Sentry Gun is disabled for three seconds after the Engineer's death.
  • Sap-and-Stab: Sap an Engineer's unattended building as bait, hide, then stab him when he returns to remove the Sapper. Alternatively, sap a turtling Engineer's building, then switch to the Knife to backstab him as a less effective variant of the stab-and-sap technique.
  • The Topstab: Sometimes paranoid Engineers place their Sentry Gun and Dispenser in a fashion that allows the Engineer to have his back to a corner, making him seemingly protected from backstabs. It is possible to kill him by climbing over his Dispenser or Sentry Gun and jumping onto his head. Face the same direction as the Engineer and crouch until you get the "Knife-raised" animation, allowing you to score a backstab.
  • Quickstab: While an unaware enemy is running towards you, let them run past you before spinning and stabbing their retreating back. This is one of the only reliable methods of backstabbing Scouts or any enemy that believes your disguise.
  • Sidestab: As the name suggests, a side stab is accomplished by stabbing the back of an enemy from the side. Because of how the characters' hitboxes are positioned, this is easier from the enemy's right than their left.
  • Dropstab: This involves the Spy waiting at a high spot, and jumping down on an unsuspecting enemy's head while holding crouch, and killing the enemy in a similar fashion as the Topstab.

Trickstabs

Trickstabs are special techniques for backstabs that involve specific movements, such as jumping over an enemy player or pretending to move one way then moving the other way. The following are most of the trickstabs used by Spies:

  • Matador: Usually most effective against support classes attempting to engage in melee combat (such as Engineers or Medics), this involves tricking an enemy into turning towards in your direction by pretending to run around them one way, then quickly moving back, strafing into backstabbing range as they turn toward, and backstabbing your pursuer.
  • Stairstab: This technique involves running up an elevated surface and jumping over your pursuer's head, landing behind or on top of them and scoring a backstab. This is less effective against more experienced players, as it is often highly predictable and can be easily countered. There are several, lesser known, variations. This can also be done on small elevated surfaces too, such as Teleporters.
  • Cornerstabs: This takes advantage of the map such that the enemy pursuing the Spy would turn a corner (which does not necessarily need to be blind), and exposing their side to the Spy, in a similar fashion to the Matador stab.
  • Circlestrafe stab: A highly advanced yet unreliable type of trickstab that is designed to counter strafing enemies who do not turn enough to fall for a matador, or enemies who backpedal. There are currently four known types.
  1. For enemies who are holding W and a strafe key while strafing into the Spy, the Spy moves into and intersects the path of the pursuing enemy.
  2. For slow, backpedaling enemies (e.g. Soldiers and Demomen), the Spy backpedals along the enemy's side and attempts a sidestab.
  3. For enemies who are strafing between two points, such as a Scout aiming towards a Spy, the Spy strafes to the opposite direction of where the enemy is strafing, and relying on the enemy to strafe back into them (e.g. A Scout moves towards the Spy's left side, the Spy moves towards his right side, and eventually the Scout strafes back into the Spy while attempting to strafe-aim).
  4. For enemies who are attempting to strafe behind the Spy, the Spy matches the enemy's movement by holding S and a strafe key, and attempts a sidestab while backpedaling.
  • Surfstab: An extremely situational stab where the Spy surfs explosive damage or enemy airblasts, and kills the/another enemy while landing on them, similar to a Dropstab.
  • Airstab: Also an extremely situational stab where both the Spy and the enemy get near each other while airborne, the stab is applied specially at high speeds, similar to a sidestab, the Spy quickly flicks his aim to the enemy's back and then stabs. To prevent the loss of your momentum while airborne due to bumping, strafe around the enemy and then stab.
  • Dropstab: Done when falling from a height and backstabbing an enemy before or right when the Spy lands.

Issues

See also: Lag compensation

  • Due to a glitch in the game, a stab that has appeared to have occurred from the front can sometimes be rendered as a backstab. Known more commonly as a facestab, these kills are now mostly the result of lag compensation by the game engine itself. Prior to many game patches, facestabs were more common due to bugs in the way the game detects a backstab. Facestabs take two forms: the "valid" stab and the "true" facestab. Most of what the recipient sees as a facestab is usually either a cornerstab or a sidestab, where on the Spy's screen, he sees it as attacking the target's back, but due to lag, the target sees the Spy attacking from the front. A valid facestab works as intended by the developers, making correct use of lag compensation. In a true facestab, the Spy appears to be attacking an enemy from the front on both players' screens, but lag compensation results in it being registered as a backstab. This is considered a bug.
  • Another community-coined term is the failstab, which refers to a backstab which should have succeeded, but instead did only normal Knife damage, despite the backstab animation playing fully and the Knife connecting. These stabs are almost always linked to the latency conditions between the server and the player. A similar variant is a stab that plays the animation and the sound effect, but does no actual damage.
  • Rarely, during taunts, the player's 'back' changes position; it becomes directly behind the player's 3rd-person camera, which means that players can avoid backstabs by moving the camera away from the Spy. This generally occurs by accident; for example, when a player positions the camera in front of them to watch the taunt themselves, making their back into their front. Facestabs can also rarely occur this way.
  • The angle required for a backstab is based on the direction the victim is looking; however, all players have models whose normal stance has their backs rotated to the left slightly, due to the way they carry their respective weapons (this is most prominent with Heavies). This means that at certain angles the player appears to be stabbing their target in the back, when in fact the player is not inside the 180 degree angle for backstabs. Equally, there are valid backstab positions which appear to have the player stabbing slightly into the front of their victim. These hit-box positions can be determined by the shoulders of the character models.

Related achievements

Leaderboard class soldier.png Soldier

War Crime Spybunal
War Crime Spybunal
Kill a Spy who just backstabbed a teammate.


Leaderboard class sniper.png Sniper

Shock Treatment
Shock Treatment
Kill a spy whose backstab attempt was blocked by your Razorback.
Consolation Prize
Consolation Prize
Get backstabbed 50 times.


Leaderboard class spy.png Spy

Agent Provocateur
Agent Provocateur
Backstab your Steam Community friends 10 times.


Counter Espionage
Counter Espionage
Backstab a disguised Spy.


Dr. Nooooo
Dr. Nooooo
Backstab a Medic that is ready to deploy an ÜberCharge.


High Value Target
High Value Target
Backstab an enemy who is dominating 3 or more of your teammates.


Is It Safe?
Is It Safe?
Backstab 50 enemies who are capturing control points.


Sapsucker
Sapsucker
Sap an enemy building, then backstab the Engineer who built it within 5 seconds.


Spymaster
Spymaster
Backstab 1000 enemies.


Triplecrossed
Triplecrossed
Backstab 3 Snipers in a single life.
Come in From the Cold
Come in From the Cold
Get a Revenge kill with a backstab.


Die Another Way
Die Another Way
Kill a Sniper after your backstab breaks his Razorback.


FYI I am a Spy
FYI I am a Spy
Backstab a Medic who has healed you in the last 5 seconds.


Identity Theft
Identity Theft
Backstab the enemy that you're currently disguised as.


May I Cut In?
May I Cut In?
Backstab an enemy and the Medic healing him within 10 seconds of each other.


Slash and Burn
Slash and Burn
Backstab an enemy, who then switches to Pyro before they respawn.


The Man with the Broken Guns
The Man with the Broken Guns
Backstab an Engineer, then sap 3 of his buildings within 10 seconds.


You Only Shiv Thrice
You Only Shiv Thrice
Backstab 3 enemies within 10 seconds.

Update history

October 25, 2007 Patch
  • Fixed a Spy backstab exploit where you could stab a player who was not facing away from you.

February 19, 2008 Patch

  • Fixed a case where a Spy stabbing from the front of a player would score a backstab.

March 1, 2008 Patch (Xbox)

  • Fixed Spy backstab exploit.

February 24, 2009 Patch (Scout Update)

  • Changed backstab handling to fix facestabs.
  • [Undocumented] Reduced stab radius to 160 degrees. Removed quickbackstabs and thus reduced the Spy's backstab range (Has since been reverted). Made backstabs quicker.

March 5, 2009 Patch

  • Increased backstab check so that Spies can side-stab again.

May 21, 2009 Patch (Sniper vs. Spy Update)

  • The Heavy and Sniper now have new custom death animations.

June 8, 2009 Patch

  • Added a backstab custom death animation to the Heavy.
  • Fixed a couple of cases where viable backstabs would fail.

August 13, 2009 Patch (Classless Update)

  • Cloaked Spies standing in valid backstab positions no longer raise their Knife.

December 17, 2009 Patch (WAR! Update)

  • Added more backstab animations.

January 13, 2010 Patch

  • Added backstab death animations for Scout, Spy, Medic, Demoman, Engineer, and Pyro. All death animations have a 25% chance to play.

October 18, 2011 Patch

  • Fixed a glitch where the Spy would take fall damage after backstabbing someone while standing on top of him.

October 30, 2014 Patch

  • Fixed the knife not playing its backstab animation when Crits are disabled.

Bugs

  • When a player for the opposing team is standing on top of the Spy, the Spy can always perform a successful backstab regardless as to whether or not the Spy's aim falls within the regular backstab radius.
  • Occasionally, when swiping at an enemy, the Spy does the backstab animation, even if it was not a backstab.
  • Occasionally, a Spy takes fall damage after backstabbing someone while standing on top of the victim, even though this was supposedly fixed in the October 18, 2011 Patch.

Trivia

  • Originally, the Spy's backstab animation was just over a second long and manifested as the current animation, but was slowed down. This was changed to the current, sped up version used today in the interests of balance. Before this change, skilled Spies would "quick-stab". This involved staying out of backstab range of the victim, and then swinging the Knife just before entering backstab range, thereby bypassing the backstab animation, but still rewarding an instant kill.
  • The Sniper's unique backstab death animation was first seen in Trailer 2 before any backstab animations were integrated into the game.

External links

References

  1. game\shared\tf\tf_weapon_knife.cpp:L395-430