Vaka

Vaka does two things to fires. It caps what a fireplace loses while nobody is there, so a single absence costs at most one fuel however long it lasted. And lights that burn resin or coal hold each unit twice as long. Cooking fires burn wood, and while you stand at one it burns exactly what vanilla says.

Features

• A fire is charged at most one fuel for any one absence. The amount is configurable.
• A fire that burns resin or coal lasts twice as long per unit, whether you are there or not. Which fuels count and how much longer are both configurable.
• Wood fires burn exactly as vanilla, to the decimal, while you are at them. Sleeping and skiptime are charged in full at the fire's own rate, because the fire was loaded and ticking the whole time.
• Covers every piece that uses the vanilla Fireplace component, including fires added by other mods.
• No new pieces, no keybinds, no UI, no new saved data. One Harmony postfix on one method.
• A log line each time you enter a world, naming the fires the light rule applies to.
• Optional logging that reports what each catch-up was worth and what it was actually charged.

How it works

A fireplace does not burn in the background. While its zone is loaded, Fireplace.UpdateFireplace runs every two seconds, asks how long it has been since the last run, and subtracts that many seconds of fuel. When the zone is unloaded nothing runs and nothing re-stamps the timestamp on the fire's network object, so the gap keeps growing. The first update after your base loads back in pays for the whole gap at once. Whether anyone was present is never part of the sum, so a base of thirty torches is thirty of those bills landing in the second you walk in.

The clock is world time, not wall time. A dedicated server only advances it while at least one player is connected, and the value is saved into the world file. An empty server is frozen and a single player world resumes exactly where it stopped. What actually drains your base is the hours other people spent online elsewhere on the map, or in single player, the hours you spent across it yourself.

Vaka caps that first bill rather than making all fuel last longer. A longer fuse on every fire would make cooking cheaper while you are stood at the campfire, which was never the problem, and a longer trip next time would still arrive at a cold base.

An absence is recognised by the fireplace object not having been running, not by the size of the gap. The game creates a fireplace when its zone loads and destroys it when the zone goes, so the first update for a new object is the one paying off however long it was away. Every later update is a live tick and is charged in full whatever its size. That is why sleeping through the night and the skiptime console command still cost full price.

Light fuels

The second rule is a longer fuse, and only for light. A fire whose fuel is on the LightFuels list burns each unit LightFuelMultiplier times as long. The defaults are resin and coal, twice as long. It applies all the time, at the fire and away from it.

It stays off cooking fires for the reason the cap is a cap. A longer fuse on a campfire makes cooking cheaper, and nobody asked for that. On a torch it only means fewer rounds of the base with a stack of resin.

A cooking station or cauldron does not ask for a campfire. It looks for the burning area a campfire carries, and the standing brazier carries one under the same name. If the rule reaches a fire with that area and a cooking station fits over it, that spot cooks on the longer fuse. Nobody has tried it. The log line below names any fire the rule reaches that carries the area.

The rule reads what a fire burns rather than which piece it is, so a torch from another mod that burns resin is covered without anything to update. Which pieces burn resin or coal is the game's own data, so each time you enter a world Vaka writes one line to the log naming the fires the rule applies to, grouped by fuel. A fuel on the list that nothing burns is named too, with "no fireplace in this world burns it".

The two rules stack. The cap is counted in fuel, so an absence still costs a torch at most one resin. The torch just has to be left alone twice as long before the bill gets there.

What it covers

Anything carrying the vanilla Fireplace component: every player-buildable fire, and any modded fire built on the same component. Numbers ripped from the running game, at vanilla rates:

Piece	Prefab	Holds	One fuel	Full tank
Campfire, iron campfire	fire_pit, fire_pit_iron	10	1h 23m	13.9h
Bonfire	bonfire	10	1h 23m	13.9h
Hearth	hearth	20	1h 23m	27.8h
Wood ground torch	piece_groundtorch_wood	4	2h 47m	11.1h
Standing brazier	piece_brazierfloor01	5	5h 33m	27.8h
Ground torch	piece_groundtorch	6	5h 33m	33.3h
Blue and green ground torches	piece_groundtorch_blue, _green	6	5h 33m	33.3h
Wall torch	piece_walltorch	6	5h 33m	33.3h

Every column is populated world time, not wall clock. Cooking fires burn wood. The wood ground torch, the ground torch and the wall torch burn resin, and the standing brazier burns coal, so the light rule reaches all four at its default. The blue and green torches burn neither.

With the light rule at its default, a fire it reaches doubles both of its last two columns. A wall torch holds a resin for 11h 7m and a full one lasts about 67 hours. A fire burning anything not on the list keeps the numbers above. The log line when you enter a world says which fires the rule reaches in your game.

In vanilla, cooking fires burn four times faster per fuel than torches do, which is why a base goes dark unevenly. A campfire is empty after about fourteen hours of other people playing, a wall torch after thirty-three, so the fires you cook and warm yourself on go out first and the lighting outlasts them. With the light rule at its default the gap is eight times.

Not covered:

• The demister ground torch (piece_groundtorch_mist). It has no Fireplace component and burns no fuel.
• Smelters, charcoal kilns, blast furnaces, eitr refineries, ovens and cooking stations. Those are separate components with their own clocks, and a smelter finishing while you are away is something players want. Worth knowing that a cooking station has the same catch-up behaviour and will turn a rack of meat to charcoal over an unload. That is out of scope here.

Nothing refills anything. There is no auto-feeder and no chest access, and a fire that was nearly empty when you left still goes out. The cap limits what an absence costs, it does not conjure fuel, so the habit worth having is to top your fires up before you log off.

One side effect worth knowing: a fire that stays lit stays able to spread. IsBurning gates the ignite loop as well as the flame, so coming home to a lit fire is coming home to one that can still catch what is next to it, where vanilla would have let it go out. Every fire in the table above has a non-zero ignite radius except the wall torch. It only triggers where the game already allows cinders, so in practice this is an Ashlands concern rather than a Meadows one. A torch the light rule keeps burning longer can spread for longer too.

Installation

Install through a mod manager, or drop Vaka.dll into BepInEx/plugins.

Requires BepInEx 5.4.2350. Built against Valheim 1.0.7, BepInEx 5.4.23.5 and Harmony 2.9. BepInEx 5 API only, not compatible with BepInEx 6.

Longhouse Core is an optional soft dependency. Vaka runs without it; see Multiplayer for what you lose.

Configuration

BepInEx/config/ezomic.valheim.vaka.cfg, written on first run. Each entry has its full comment in the file.

Setting	Section	Default	Effect
Enabled	[Vaka]	true	Whether Vaka does anything. Off leaves the plugin loaded with both rules off: every absence is charged vanilla's full bill and every fuel burns at vanilla's rate. Useful for telling the two apart without uninstalling.
MaxFuelPerAbsence	[Vaka]	1	How much fuel a fire may lose to a single absence, in the units the hover text counts. 0 makes an absence free. A large number restores vanilla.
LightFuels	[Vaka]	Resin, Coal	Fuel items whose fires burn longer, by prefab name, separated by commas. Empty turns the light rule off.
LightFuelMultiplier	[Vaka]	2	How many times longer each unit of a light fuel burns. 1 turns the light rule off. Anything below 1 counts as 1, so no fire ever burns faster than vanilla.
Verbose	[Diagnostics]	false	One log line per fire every time one comes back from being unloaded, and each time you enter a world a list of every fireplace with its fuel and burn rate. See Checking that it works.

MaxFuelPerAbsence is counted in fuel units rather than seconds, so it means the same thing on a torch burning resin and a hearth burning wood, and on fires added by other mods. It is also one press of E: refuelling adds exactly one unit per press whatever the fire is. It never affects a fire you are standing next to, whatever you set it to.

LightFuels takes item prefab names, such as Resin or Coal, not the names shown in game. The Verbose list prints every fire's fuel under exactly that name, so if you want another torch covered, find it there and copy its fuel into the list.

BepInEx writes every entry to disk on first run and the saved value beats a new default in code. If a later version changes a default, edit the cfg as part of the same update.

Multiplayer

Everyone needs Vaka, at the same version and build.

Whichever client owns the fireplace's network object does the arithmetic, and ownership moves every two seconds to whichever player's active area covers the fire. One person without Vaka walking up to your base pays the absence off the vanilla way, for everybody, with both logs looking reasonable. Installing it on the server alone does not help: a dedicated server never sets a reference position, so it is never a candidate owner for a player-built fire and there is no host simulation to put the cap in.

The light rule has the same weakness. A torch burns at whatever rate its current owner's game says, so while a player without Vaka owns it, it burns at vanilla speed.

With Longhouse Core installed, Vaka registers with its version check and the server rejects clients whose version or build id does not match. The host's Enabled, MaxFuelPerAbsence, LightFuels and LightFuelMultiplier then apply to connected clients in memory, without writing their own config file, and their values come back on disconnect. Verbose stays local to each player.

Without Core, Vaka still works on your own machine, but nothing stops a client that lacks it from removing the cap for everyone, or from burning your torches at the vanilla rate.

Checking that it works

Hover text draws fuel rounded up to a whole unit, so a fire that quietly lost a third of a log reads the same as one that lost nothing, and both read the same as a mod that never loaded.

For the light rule, read the line Vaka writes to BepInEx/LogOutput.log when your character appears in a world. It starts with "Light fuels last 2x as long" and names every fire the rule applies to, grouped by fuel. If the rule is off, the line says so and why. On a server it already reflects the host's settings. It is written again if a light setting changes while you play, whether the host changed it or you did through a config manager. A dedicated server never writes it, because it has no character of its own.

Set Verbose = true. Every catch-up writes one line to BepInEx/LogOutput.log naming the fire, how long it was away, what that was worth in fuel and what it was charged, including the times the cap did not apply. Walk far enough from a fire that its zone unloads, wait a few minutes, walk back, and either there is a line with numbers in it or the mod is not running. It stays silent about unlit, switched-off, roofed and infinite-fuel fires, which were never going to spend anything.

Leaving a world overnight proves nothing in either direction. World time is saved with the world and only advances while somebody is online, so quitting and coming back bills close to zero whether the mod is installed or not.

For a conclusive test, use a throwaway character in a throwaway world, because skiptime permanently marks a character as having used cheats:

1. Place a ground torch outdoors on open flat ground. The cover check raycasts upwards from just above the torch, so anything solid within roughly a metre overhead stops it burning at all, which passes in both arms of the test.
2. devcommands, then setfuel 6. You cannot reach a full 6 by hand, because refuelling refuses once the rounded-up value hits the maximum, so a hand-filled torch sits around 5.02.
3. Walk more than 150m away so the zone unloads. Run skiptime 200000. Walk back.
4. With Enabled = false the torch reads 0/6 and is dark. With it true it reads 5/6 and is still lit.

Use at least three times the cap. With the light rule on, one resin is 40,000 seconds of a torch's time, and skiptime 40000 costs it exactly one fuel whether the cap applied or not, which looks like a failure and is not. Do one skip and let one tick land: several skips in a row are several separate absences, each capped on its own, which drains the torch and reads as no cap at all. Running skiptime while standing at the fire shows nothing about the cap, because that is not an absence.

It does show the light rule. Same throwaway world:

1. Place a ground torch outdoors. devcommands, then setfuel 6.
2. Stay next to it and run skiptime 30000.
3. With Enabled = false it burns 1.5 resin and reads 5/6. With it true it burns 0.75 and still reads 6/6.

The torch is loaded the whole time, so the cap plays no part in this one.

Troubleshooting

Nothing in the log and fires still go out. Check the startup lines. Vaka patches a private method matched by name, and if Fireplace.GetTimeSinceLastUpdate is not in your build of the game it logs an error saying it is doing nothing and fires burn the vanilla way. A game update is the likely cause.

A config change had no effect. BepInEx keeps the value saved on first run. Edit the cfg rather than expecting a new default to apply.

Fires still drain on a server. Confirm every connected player has Vaka. Without Longhouse Core nothing enforces that, and one client without it is enough.

Nothing is logged for a short trip. Nothing is trimmed until the bill passes one fuel, which is an hour and a half of populated world time for a cooking fire and eleven hours for a torch burning resin under the light rule. Under that, the bill is already less than the cap allows.

A torch still burns at the vanilla rate. The light rule goes by fuel, not by piece. Check the log line from when you entered the world: a torch missing from it burns something that is not on LightFuels. Turn on Verbose to see what it burns. Switched on in game through a config manager, the full list is written straight away. Set in the cfg file, it appears the next time you start the game and enter a world. Add that name to LightFuels if you want it covered.

Bug reports

Discord, or the issue tracker. Useful to attach:

• BepInEx/LogOutput.log, ideally from a session with Verbose = true.
• AppData/LocalLow/IronGate/Valheim/Player.log if a vanilla mechanic broke. Gameplay exceptions land there rather than in LogOutput.
• Whether you were on a server or in single player, and whether Longhouse Core was installed.
• BepInEx/config/ezomic.valheim.vaka.cfg.
• The prefab name of the fire, if it is one specific piece behaving oddly.

Bugs and ideas

Both go to the site. longhouse.thijssensoftware.nl/bugs is for anything broken, and longhouse.thijssensoftware.nl/ideas is for what a mod should do next. You can vote on other people's ideas there as well.

Signing in takes a Steam or Discord account. I work from that list, so the votes decide what I pick up next.

Discord

discord.gg/hJzAVaZ5wb for mod information, updates, support, bug reports and compatibility questions.

Server

There's also a small EU server running the pack if you want somewhere to play. Details are in the Discord.

Part of Longhouse

Vaka ships in the Longhouse modpack, which pins exact versions of its member mods. It behaves the same installed on its own.

Changelog

CHANGELOG.md carries the release history and the reasoning behind the design calls, including why the mod was renamed from Ember before release.

Licence

MIT, see LICENSE. By Robbin Thijssen, Thijssen Software.