Fallout New Vegas
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About this mod

Modifies detection mechanics to simulate a stronger cover-based style of stealth gameplay. Also adds hotkeys to enable pseudo leaning while in chase camera view. Optional adjustments can be made to combat mechanics and stealth boy functionality.

Now also hosting Xilandro's True Leaning mod, enabling rudimentary 1st person leaning

Permissions and credits

The intent of this mod is to establish stealth mechanics in Fallout: New Vegas that more closely resemble the experience of Looking Glass style Immersive Sims such as Thief or Deus Ex. NPCs have a narrower cone of vision but are more likely to detect you at a distance. Hiding in the shadows is less effective when in close proximity. It's now possible to run up behind a target and assault them undetected.

Also available is an updated version of Xilandro's True Leaning mod, which allows the player character to lean in 1st person.

NOTE: If you are using Project Nevada, be sure to review the Known Exceptions section for instructions to ensure compatibility.

1) Version History
2) Known Exceptions
3) Stealth Changes
4) Combat Changes
5) Stealth Boy Changes
6) Presets
7) True Leaning
8) Installation and Compatibility
9) Fallout 3
10) Recommended Mods (new!)
11) Notes and Credits

- Compass Fix option in to help alleviate (not solve) issues with compass markers and VATS
- NPC detection range may now be adjusted separately for interior and exterior locations
- Chase camera features rebuilt from the ground up and may now be fully disabled for players using alternative mods
- Creature Buff combat option available to make wasteland creatures more dangerous to the player
- Reorganized MCM menu for better clarity and some additional customization
- (True Leaning v2.01) Several fixes pertaining to weapon discharge and reloading while leaning
- Added an updated version of Xilandro's True Leaning mod to the files section
- Optional out of doors detection reduction during night hours
- Addressed a flaw in prior versions' LoS detection algorithm
- Setting detection range over 5000 is now permitted under the Low Risk experimental option
- Miscellaneous under the hood improvements
- Separate ESP for Stealth Boy features, preserving Project Nevada compatibility for the base mod.
- Lowered 3rd person camera option for Children of the Wasteland mod.
- 3rd person camera aiming aid is now optional.
- Optional "schizophrenia" effect for stealth boys.  When toggled, usage may randomly adjust some character stats.
- Enhanced "Experimental Values" option added to the MCM to help mitigate the chance of mod instabilities.
- Corrects a typo/bug that had been causing important functionality to fail. (sorry! my bad)
- Compatibility option to help prevent VATS bug (see Known Exceptions below).
- Hotkey support for toggling Stealth Boys on and off to conserve their charge.
- Option to lower the centered camera in 3rd person view.
- Chase camera will now attempt to center to your weapon barrel when unholstered, making aiming easier in 3rd person perspective.
- Auditory detection now works properly! Quietly dashing behind NPCs is possible, depending on equipment weight and Sneak skill.
- Maximum NPC detection range can now be adjusted from the MCM menu. Raising this may give sniper PCs more of a challenge.
- NPC's bonus from being in an alert state is no longer impacted by their Perception score (which had made detection checks feel arbitrary).
- Detection events generated by quiet kills (e.g. w/ knives or silenced firearms) are affected by the player's Sneak score.
- Silent Running perk is functionally useful again in that it allows the PC to dash quietly while wearing heavier equipment.
- Deus Esque default crouch speed raised to 42% of run speed.
- Fixed a potential AI instability for PC's with Sneak above 80.
- Fixed the Stealth Boy timer in the MCM menu from being non-operational.
- Added Fallout 3 compatible esp with basic detection and AI behaviour mechanics.
- Improved architecture to make the mod more stable and efficient from behind the scenes. NOTE: it is highly recommended that you make a clean save before updating to this version.
- Settings Presets, allowing you to change your gameplay experience at the push of a button.
- More sophisticated Stealth Boys with customization from the MCM menu.
- Optional combat bonuses to enhance "stealth shooter" type of gameplay.
- The Sneaking indicator that appears when crouched may now be optionally turned off.
- Revised sound detection; the PC now makes more noise when moving while standing than when crouched. Crouched movement noise has been slightly reduced.
- Default "lean" effect and crouch speed have been reduced, but are now adjustable from the MCM menu.
- Default NPC Cone of Vision has been raised again to a range of 120-180°, based on values from Dishonored and Deus Ex.
- Changed the NPC Cone of Vision radius from the range of 30-130° to 80-150°. i.e. NPCs have better peripheral vision.
- Fixed bug that was preventing the CoV difficulty slider from functioning.
- Increased the time NPCs will search for the PC once stealth is broken. The timer duration is affected by your Sneak skill.
- Increased movement speed when crouched.
- Doubled the distance NPCs are willing to travel to combat the PC once stealth is broken. Sneak failures may result in more spectacular battles.
- Fixed a bug that was preventing some game settings from being updated on load.
- You can now adjust damage threshold from the MCM menu, allowing you to make combat much, much deadlier. (not set by default but 200% is recommended)
- Improved Toggled leaning. Pressing a lean button while still in lean will center the camera. Toggled lean is now set as default.
- Tweaked AI Behaviour AI to (hopefully) make it a little less erratic. These changes are experimental.
- Added Mod Configuration Menu support enabling the user to adjust various features and settings.
- Lean functionality may now be disabled or set to toggle mod so that user can tap the lean keys rather than have to hold them down.
- You may now select your own hotkeys for the Lean function. The default set has been changed to the bracket keys.
- The 3rd Person camera maximum distance is now adjustable.


VATs functionality and missing compass markers:
Because of some core features of this mod, NPCs may fail to appear as markers on the UI compass and VATS may not always visible targets.  A workaround for this problem is available in the MCM Menu called the "Compass Fix".  This fix will restore some compass and VATS functionality though it may sometimes cause anomalies in NPC detection.  Leaving the fix off will offer the most reliable stealth experience.

3rd person "leaning" doesn't move far enough:
When FNV boots up, for some reason it scales down the distance that the chase camera will move when leaning. I don't know why this happens but an easy fix is to simply move the scroll wheel on your mouse (i.e. change the zoom level in 3rd person) and the game resets to the proper distances for the remainder of the session. So if you find that the leaning is a bit constrained, just adjust the zoom a bit and the problem should go away.

Project Nevada Compatibility:
Some configuration is required to keep Project Nevada from conflicting with Cover Based Stealth.  To ensure that stealth and detection are working properly, PN's stealth settings and the Experimental Detection AI must be disabled.  Enabling either of these options will override Cover Stealth's functionality.  If you wish to use Cover Stealth's sneak indicator, the corresponding feature must be disabled in PN.  Alternatively you can set the Sneak Indicator option to "Ignored" in Cover Stealth's MCM menu if you prefer to use PN or any other mod to set your sneak indicator.  Finally, the Advanced Stealthboy mini mod is incompatible with PN's enhanced stealth boy settings.  Installing the Bash_Stealthboy.esp will over-ride PN's stealth boy functionality.


Cone of Vision: This is the NPCs equivalent of your FOV setting, it determines the NPC's peripheral vision or how much it can see of the world around the direction it's looking. The vanilla FNV value was 190°, which meant that NPCs could actually see slightly behind them.

The default modded value is a range between 180° for characters with a Sneak skill of 0 to 120° for characters with 100 Sneak, though this range may change depending on your selected preset. If you feel that the NPCs' field of view is too narrow or too wide, you have the option of setting your own range from the MCM menu.

Distance Attenuation: This modifier affects an NPCs detection score based on distance to the player. The mod changes the slope of attenuation so that if an NPC is able to detect the player at all, it will occur from a much further range. This means you'll know sooner rather than later if you're detected. One of the things that frustrated me in vanilla F3 and FNV was sneaking up on an enemy with a melee weapon and having them hone in on my position when I was five feet away. Now NPCs are more apt to be alerted to your presence while you are at a greater distance so that you aren't left completely vulnerable during a failed Sneak attempt.

PC Sneak: The player's Sneak value has diminished impact on line of sight detection checks. If you're standing five feet in front of an NPC, they're going to see you whether your sneak is 0 or 100. Lighting still affects visual checks so you can try to hide in shadows but it's more effective from a distance. Sneak still affects auditory detection checks so having a high Sneak score will enable you to crawl up behind NPCs while wearing heavier equipment.

NPC Perception: NPC's do not receive a bonus from their Perception score, but are still more likely to detect the PC, particularly by sound, when in an alerted state. This was done to prevent detection check from seeming arbitrary.

Auditory Detection: Unlike vanilla FNV, "running" does not impart a penalty when crouched. This means that all players start the game as if they had the Silent Running perk, so you never have to hold down the Shift key when sneaking. However, the game does now differentiate between crouched movement and standing movement. Running while standing does impart a penalty, making NPCs much more likely to hear you.

These detection checks are modified by the weight of your equipment (armour + hat + weapon), the PC's Sneak score, and the presence of the Silent Running perk. There's no hard and fast rule as to what weight of armour you can sneak with so you'll have just to try experimentation. Generally speaking, PCs with a poor Sneak score can crouch with light armour and dash in civilian armour (e.g. jumpsuit) without being detected while those with a high score can sneak in powered armour and dash in medium armour.

Peeking: This is the ability to look around corners when in 3rd person view, which is useful for observing NPCs to determine the best opportunity to  move.  To Peek, go to your chase camera view and then press hotkeys that you selected during mod initialization. Hitting the left hotkey (usually 'Q' or '[') will move the camera to the left while hitting the right hotkey (usually 'E', 'R' or ']'). You may select your own hotkeys from within the Mod Configuration Menu.

There are two modes of camera leaning: "Toggled" and "Press to Lean". Toggled Lean mode which will move the camera to the left or right after tapping the appropriate key once. Then press that same key again to center the camera, or the opposite key to move the camera to the opposite side of the PC. Press to Lean requires you to press and hold the a lean key to move the camera, which will then automatically center after that key has been depressed.

To perform leaning in 1st person, I recommend using Xilandro's True Leaning mod, which can now be conveniently found in the files tab.  Special thanks to Xilandro for allowing me to update and host his mod.

Crouched Movement: The rate at which the PC moves when crouched/sneaking is now adjustable from the MCM menu or by selecting certain presets. The FNV default value is 57%. The comparable Deus Ex value is 42% and, for Dishonored, 50%.


Adjustments to the combat mechanics are entirely optional with this mod. Only some presets enable them by default and they may be turned on or off at whim from the MCM menu.

Lethality: This determines the overall damage output of every weapon in the game, wielded by PC and NPC alike. A high lethality modifier will make combat faster and deadlier while a low value will make it slower. If you're going for a Deus Ex style experience then I recommend a value of 200-300%, which is two or three times deadlier than vanilla FNV.

Sneak Attack Criticals: These are actually different from normal critical attacks. In vanilla FNV, on top of the normal critical bonus, sneak attacks do two or five times more damage depending on whether you're using a ranged or melee weapon. From the MCM you can adjust this bonus or you can do what I do and turn off sneak attack criticals altogether (though normal Luck-based criticals are still possible).

Backstab: The Backstab bonus is intended as an alternative to sneak attack bonuses. When attacking a target's rear arc, the player gets a 50% damage bonus with ranged weapons and a 200% bonus with melee weapons. Explosive weapons also receive a 66% bonus, regardless of arc, provided that the player is not in the target's line of sight. Unlike sneak attack criticals, Backstab attacks can be made even while an enemy is actively searching for the player. This bonus is intended to simulate the 12X (yes, twelve times) extra damage that Deus Ex would award a player for hitting a target's weak spot.

Heavy Nullifier: This is a damage bonus against targets with a very large number of hit points. These "heavy", damage soaking units tend to require long, drawn out battles to defeat. That conflicts with the notion of stealth style play which favors waiting for the opportune moment to make a quick, surgical strike. At the same time, the Heavy Nullifier does -not- impact normal grunt level targets or Heavies that have already been weakened. Your first strikes against a Heavy will always be the most effective, so it's best to try to stack as many benefits as possible. The exact bonus is 25% versus targets with 200 hitpoints or more (e.g. super mutant brute) and 100% versus targets with 500 hitpoints or more (e.g. deathclaw).

Creature Buff: This is a damage penalty against wasteland creatures that use close range attacks, such as geckos, scorpions, or deathclaws.  For players who like to use high damage mods, these enemies are often killed before they can become a danger.  The Creature Buff will make these enemies tougher to kill while also giving them the ability to pierce your armor.  Companions and other NPCs are not affected.


By using the Advanced Stealthboy minimod included with Cover Based Stealth Mechanics, the first change you'll notice is that you will now receive a 30 and 10 second warning on your interface before a stealth field is going to dissipate. This is essential since the duration of a stealth field is now dynamic based on player skill. Stealth field charges also stack in duration so that if you activate one while the field from a previous stealth boy is still running, you get the full sum of the new charge with the remainder of the last one. You can set the charge duration and the applicable skill from the MCM menu.

You can now assign a hotkey to toggle Stealth Boys on and off. By doing this you can conserve your stealth field by only using it when you need it, rather than let it run out for each use. Based on your selection of preset, toggling off a stealth field that is in mid-charge may drain part of the remaining charge.  This drain is design to prevent abuse of indiscriminately toggling the stealth field and may be altered or turned off in the MCM Menu.

There are three additional options you have to affect Stealth Boy behaviour. The first determines whether or not making an aggressive action prematurely negates a stealth field. What this means is that if you're currently stealthed and you make an attack against an enemy, the stealth field automatically dissipates, regardless of how much of a charge remained.

The second option is to determine whether or not activating a stealth field automatically ends combat. In vanilla FNV the enemies around you would automatically forget about you and pretend you don't exist and walk away on activation of a Stealth Boy. With this setting turned off, Stealth Boys will no longer be a get-out-of-combat-free card.

The third option, which must be manually selected in the MCM menu as it is not default to any of the presets, is Schizophrenia.  Every time a stealth boy is consumed while the schizophrenia option is toggled on, there is a possibility that one of the player character's SPECIAL points will be shifted from one ability to another.  The player will never be left with more or less points than they had before, they'll just be altered to favor one ability over another.  This is based on lore from Fallout: Van Buren which put it that stealth boys had the same mental health impact on humans as it does to Nightkin in FNV.


When the mod is first initialized, a pop-up menu will appear asking you to select a Preset. These are a collection of mod settings that determine your default gameplay experience in a single broad stroke. If you have the MCM menu installed, you can make minute adjustments from there. If you don't have to MCM menu and wish to return to this menu, simply press your two "lean" hotkeys simultaneously and it will reappear after a few seconds.

The available presets are as follows:

Basic Cover Stealth: This preset applies the cover stealth mechanics but leaves combat and stealth boys alone. It's the basic "nuts and bolts" preset that delivers the main detection features without affecting combat. The default NPC Cone of vision is a range of 120-180°, the distance attenuation exponent is 0.8, making NPCs more far-sighted, and lean camera is set to Toggled mode.

Bashar's Selection: These are the preferred settings of the mod designer (that would be me). It applies the same stealth settings and Basic Cover Stealth but makes adjustments to combat and Stealth Boys. Crouched speed is 50% of running, comparable to Dishonored, and the Sneaking indicator is obscured but not hidden.

Weapon lethality is 300%, or three times normal. Sneak Attack Criticals have been disabled but the Backstab bonus has been implemented in its place. The Heavy Nullifier is also enabled.

Stealth Boys have a duration range of 20 to 120 seconds based on the PC's Sneak skill. Activating a Stealth Field won't automatically pacify nearby enemies. Aggressive actions will prematurely disable a stealth field.

Deus Esque: This preset is derived from the game settings of Deus Ex. NPC Cone of Vision is a fixed 160° and crouched movement speed is 42% of normal. Lean mode is Press to Lean. The Sneaking indicator is completely hidden. Stealth boys have a duration of 12-50 seconds, the same as Thermoptic Camo, and based on the PC's Repair skill. The stealth field does not automatically pacify enemies.

Combat is identical to the Bashar's Selection preset.

Bethesda Traditional: This preset will set all of the mod's adjustable settings for stealth and combat mechanics, the interface, and Stealth Boys, to the FNV default. NPC's Cone of vision is 190° and the distance attenuation exponent is 2, making NPCs very near-sighted. Lean is disabled.

This will not completely shut off the mod because there are still some adjustments being made in the background, namely pertaining to AI behaviour, but instead serves as a basis from which the player can make minor tweaks to their gameplay experience.

7) True Leaning:

Xilandro has given me permission to update and host his old True Leaning mod, which allows players to peek around corners in 1st person.  By his request, True Leaning will not be fully integrated into Cover Based Stealth Mechanics; however, the two mods function compatibly side by side.  Note that the lean animations do not have collision detection, making it possible to peek through walls, which means this mod could potentially be used as a cheat.

Optional features included in Version 2.x:
  • An additional lean animation which does not extend as far as the original.
  • Ability to zoom in with a weapon while leaning.
  • Ability to activate objects while leaning. (potentially buggy, for advanced users only)

You can set your lean hotkeys and other preferences in the MCM menu.  Some options will be greyed out if one of your lean keys is the same as your Activation Key ('E' by default).  To unlock these features, simply change the offending lean key to something else and those options will become available.


To install, simply place the esp files (Bash_Stealth.esp and Bash_Stealthboy.esp) in your data directory and apply them to the load order as per normal.  If updating from an older version, it is recommended to make a clean save before installing the new version.  At the very least you should check your options in the MCM menu to ensure that they are to your preference.

NVSE is required for the mod to function properly. The Mod Configuration Menu is recommended if you want to change the default settings, but not necessary to run this mod.

I personally do not use Project Nevada and do not test with it; however, several users of this mod have confirmed that is compatible with the Cover Based Stealth Mechanics mod (Bash_Stealth.esp); however, you must disable both PN's stealth mechanics and it's experimental AI detection from within the game to avoid conflicts.  Trying to run Project Nevada's stealth system and Cover Based Stealth concurrently won't crash your game, however the two mods will conflict with one another, resulting in weird detection checks.

The Advanced Stealthboy mod (Bash_Stealthboy.esp) is not compatible with PN as it will over-ride PN's stealth boy script with its own.  You can use both mods together but you will be losing PN's stealthboy features in favour of the ones provided by this mod.  This mod also changes one vanilla object, the StealthBoy, therefore you must place the esp below any other mods that may affect the stealthboy in your load order.

This mod should work fine with any other mod that doesn't affect game settings pertaining to detection checks or the chase view camera. If you are concerned that another mod may be affecting stealth or detection mechanics, you can try going to the MCM menu and the Periodic Refresh option to a non-zero value. This will routinely reset the game settings to the modded values.


Officially I endorse the Tale of Two Wastelands mod for those players who want to visit the Capitol Wasteland. This mod was tested with TTW and is compatible without any additional configuration required. But for those players who prefer to stick to the Fallout 3 engine, I've included as a miscellaneous file an esp that will install a stripped down version of this mod. Only the basic detection mechanics and AI behaviour changes are incorporated. Missing is the ability to change settings in-game, the 3rd person camera, combat modifiers, and Stealth Boy changes. FOSE is not required for this esp to function, but it is recommended that you place it in your load order under any other mods that might affect stealth or the AI.

Note: It's been reported that the Fallout 3 esp may cause a crash to desktop after several hours of play.  While a new version may be forthcoming, a temporary workaround in the mean time is to uninstall the mod, make a clean save of your game, and then reinstall the mod.

10) Suggested Mods:

While there are a ton of good mods I could recommend, this list focuses on those I believe function particularly well in conjunction with Cover Based Stealth Mechanics.

Combat Enhancer and Enemy AI - Tactics.  These two mods both affect NPC behavior in combat and work well with one another.  I regard them as an essential part of my load order as they transform your opponents from dumb brahmin to hardened battle cattle.

DT Multiplier and DR Adder.  For players who like to play FNV with high damage settings, this mod addresses the issue of Damage Threshold's diminishing value.  It allows you to modify the DT and DR rating of all armor pieces in the game, vanilla or custom, from the MCM menu based on class (light, medium, heavy, power).  This can make armor more (or less) relevant in deadly engagements.

Enhanced NPC Awareness.  This mods helps cover the blind spot that Cover Based Stealth Mechanics has with long range combat reactions and should improve the experience of sniper characters.  It's not as important for players focused on CQC but may still be worth checking out.


While I believe that the mod is now "feature complete", I will continue to make tweaks and adjustments as I learn more about the FNV game settings. It's very difficult adjusting much of the game's behaviour because a lot of these settings are undocumented, meaning the only way to figure out how they function is through experimentation. The values and features will be adjusted as I continue to test it in game and as I receive feedback from the player base.

For a stand alone backstab damage mod, you can use wobbataco's Backstab Damage Bonus in lieu of Cover Stealth.

Special thanks to Jahandar for the Centered 3rd Person View mod, which was instrumental in pointing me in the right direction of how to implement 3rd person peeking.

Additional thanks to CyberP, author of the GMDX mod for Deus Ex, who helped in giving me definitive information on that game's stats.

Testing thanks goes to kopija and burndtdan for helping bring the VATS bug to my attention. Kopija's efforts were particularly helpful in trying to solve it. Also to danddodgydealer for bringing the v1.06 typo bug to my attention. Credit also goes to Befo, zanyoutlaw, and camycamera for confirming Project Nevada compatibility.  Thanks also to BigBritishGuy and thiagojaschek for bringing an interface issue to my attention.  Thank you to VWgolfR1 for confirming some of the experimental values, allowing the extended NPC alert time to be enjoyed by all, and offering valuable test feedback.

Kudos also go to Pelinor for developing the excellent Mod Configuration Menu. This mod wouldn't have half the features it does without you.