I thought it was ridiculous that I could light up an entire street or enemy base with my Pip-Boy light and no one would notice. That's okay, it wasn't a main focus of the vanilla game. It is a main focus of the way I want to play it though, so I made this mod.

Below are some videos demonstrating the new mechanics. Disclaimer:  I have other mods installed that affect darkness, sneaking, shadows, etc. and cannot test vanilla at this time. The point of the videos is that with this mod, you can hide in darkness, you are revealed by lighting, and most importantly, your own light will give you away. These new mechanics will work whether you install other mods or not.





Video Two Timestamps
Pip-Boy light 1, up close - 00:00
Pip-Boy light 2, further back - 00:43
Pickpocket a ghoul - 01:40
Walk out of shadow and get detected 1 - 02:35
Walk out of shadow and get detected 2 -02:52
Stand up and die - 03:32
Touch a ghoul, step on bright spot and die - 04:29
I think I rustled a grass patch? - 05:19
Pip-Boy light 3 and 4 - 05:45




TL;DR

• Install F4SE
• Put this in your Fallout4Custom.ini:
  

[Controls]
fPipboyLightDelay=0.5

• The mod is 99% script and doesn't modify any settings or assets just by being installed. I like to load it last-ish but it shouldn't make a difference.
• Set your interior and exterior max light levels using the instructions in the holotape. You need to use your actual Pip-Boy light to find these values, not a different light. Mining and PA helmet won't affect player light level so they can't help us. If you have modified your Pip-Boy light such that it doesn't affect player light level (unidirectional like mining helmet), you will need to temporarily disable that mod so you can set the maximums without it.
• Watch your light on/off status doesn't get out of sync (rare). Resync it if it does. That's it!
  

Core Features

• In darkness or shadow, you are now undetectable and appear as a shadow when sneaking.
• Your Pip-Boy light or any other equippable player light using the same control will give you away immediately, regardless of line of sight. The mining helmet and power armor helmet lights work properly, as should any mods using the same control/key. Firing a weapon will do whatever it normally does (for now).
• The shadow effect and buffs are applied/removed based on the player's light level, not just equippable light usage, so as the sun, spot lights, and shadows move, they conceal or reveal you.
• Sneaking in the light behaves the same as it normally would in your game.
• A gamepad will work just fine, that's how I play, but the hotkeys won't be available (they are not necessary).
• All options can be customized through the holotape.
  



Holotape Options

• Enable/disable mod while leaving it installed.
• Resync your light status (on/off) to the key/control - Yes, we are tracking a key/control via script, isn't that trashy? It works fine, check the notes at the bottom.
• Disable sneaking in power armor - You're a tank and the screen shakes when you run, come on! Still, your game, your choice.
• Disable crouching in power armor - Prevents confusion about whether you're actually sneaking.
• Disable light matters in power armor - Allowed to sneak but disables the light-based mechanic.
• Set your light level thresholds - When do you want to disappear into shadow? Be undetectable all the time when crouching or never if you want. Separate settings for interior/exterior.
• Set your light level maximums - I don't know what your game's maximum interior and exterior light levels are or if they are different than mine. You must configure these two values using the instructions in the holotape menu.
• Hotkey options - Independently enable hotkeys to show light on/off status, resync light on/off status, and display light levels.
• Status options - Independently turn off light status, light level, and detection event messages.
• Shader options - Choose from:  None, Stealth Boy, Shadow, Shadow w/ Edge (dark gray), Shadow w/ Edge Color (dark blue), Experimental Dissolve (works but stupid, placeholder for some other time)
  

Installation

• The Fallout 4 Script Extender (F4SE) is required in order to detect control/key press/release events.
• Also add the below to your Fallout4Custom.ini. This is the vanilla hold-duration required to toggle the Pip-Boy light on/off. This mod is tracking the usage of that control/key, so the delay MUST match the script.
  

[Controls]
fPipboyLightDelay=0.5

• Install the mod using your preferred method (MO, NMM, straight into your game folder, etc.)
• You can load/install the mod into an existing save, but backup your save first, it's not my baby it's yours.
• Turn your Pip-Boy (or other equippable light) OFF before enabling the mod (else the light will be out of sync with the code, but you can just resync).
• Once in game the player will be given the item "[Settings] Light Matters Holotape" for configuring the mod.
• If you are missing the holotape for any reason, you can craft it at a chem bench under "Utility" (no resources required) or get it from the console by typing:
  

help "light matters" 4

• ...then hit PGUP until you see the "NOTE" item. Use that ID instead of X's below to spawn the holotape at your feet:
  

player.placeatme XXXXXXXX

• Enable the mod using the holotape.
• Set your light level maximums - I don't know what your game's maximum interior and exterior light levels are or if they are different than mine. You must configure these two values using the instructions in the holotape menu. You need to use your actual Pip-Boy light to find these values, not a different light. Mining and PA helmet won't affect player light level so they can't help us. If you have modified your Pip-Boy light such that it doesn't affect player light level (unidirectional like mining helmet), you will need to temporarily disable that mod so you can set the maximums without it. It's otherwise easy, here is what the instructions say:
  

For exterior max:
"Go outside to an exterior cell in the day time, stand in the sun, and turn your light on.
Enter sneaking to display your light level and select it..."

For interior max:
Go inside an interior cell and turn your light on. Enter sneaking to display your light level and select it..."

• Lastly, you'll want to set the interior and exterior light value *thresholds* that determine when your character will be hidden in darkness or shadow. There's no correct setting here, it's subjective.
• Have fun!
  

Uninstallation

• Disable the mod using the holotape before you uninstall it, then just remove it from your load order.
• *Technically* this is ill advised and you shouldn't be removing scripted mods mid-game. If you understand the potential consequences, go for it, but backup your save first.
  

Updates

• If no script changes are made, you can safely disable the mod in the holotape only and install the updated version.
• If script changes are made, you might get away with disabling the mod in the holotape, loading your game and saving once without the mod in your load order, then installing the new version. I would have no way of knowing this for sure, so it is very much not recommended. Don't break your save game. If you want to update, start a new one.
  

Questions
What's the point of the vanilla sneak perks and buffs then?
Sneaking in the light (rather, above your light level threshold) uses the same mechanics as it would normally in your game.

What happens if I use a stealth boy?
If you're sneaking in the dark, I don't know.
If you're sneaking in the light, it's your normal game's stealth boy mechanics.
If you're using your light, the stealth boy is pointless because you are broadcasting detection events.

What about chameleon armors?
I don't know at this time, untested.

Compatibility / Load Order
This mod is 99% script and doesn't modify any settings or assets just by being installed. I like to load it last-ish but it shouldn't make a difference. I'm currently using it just fine with the following mods that potentially affect lights, shadows, brightness, and darkness in my game:

• Subtle ENB
• Darker Nights
• Brighter Settlement Lights
• Legendary Lamps (300%, omnidirectional)
  

There are some sneaky mods out there I'd like to try with this, but I haven't yet so I won't speculate.

Notes / Known Issues
You can't use Papyrus to ask the game if the Pip-Boy light is on or not. I've seen and made a lot of round-about attempts. Short of hooking into the EXE with F4SE (which I cannot do currently), I don't know how you would do it. I'd rather do it this not so great way than not have it at all, so we track when the user releases the Pip-Boy light control/key.

This means it's *possible* (though rare) for the control/key press and the code to get out of sync, especially if the game turns your light off in situations I haven't identified. Currently the following behavior is identified and synchronized:

Teleport (teleport doors, fast travel, anything that involves a load screen)
Teleport from EXTERIOR to EXTERIOR, game leaves light ON
Teleport from EXTERIOR to INTERIOR, game leaves light ON
Teleport from INTERIOR to EXTERIOR, game turns light OFF
Teleport from INTERIOR to INTERIOR, ____? (untested, the code is written as "game leaves light ON")

Power Armor Enter/Exit
On both enter AND exit, game turns light OFF

Aiming/Using Sights
If you try to toggle your light while aiming, the game will ignore you.

You can resync your light any time in the holotape menu or by using the hotkey, also enabled via the holotape menu.

Other known "quirks":

• I can't make a "weapons visible" version of the stealth boy effect at this time.
• If you get into furniture while sneaking, the effect and shader should be cancelled but this doesn't always happen because OnSit() and OnGetup() events don't reliably fire. If you stand up and sneak twice-ish, it will fix itself. Worst case toggle the mod off and back on in the holotape.
• I *think* some shadows and/or lights are fake and might not affect playerLightLevel as much as expected. There are some other mods that might address this but I have not tried them yet.
  

My Mods
Light Matters for Sneaking
DIY Rad Storm Colorizer (Edit Weathers as Bitmap Images)