Fimbulvetr

The great winter doesn't wait for you to finish shovelling.

What it does

In the vanilla Deep North, snow you shovel away or trample down never comes back. Fimbulvetr lets it fall again. Shovelled paths, trenches and footprints slowly fill back in towards the ground's natural snow depth, and a blizzard buries them fast. Broken Ice Sheets freeze over again too.

• Weather-driven. In clear weather, snow drifts back slowly. In snowfall it builds up faster, and in a blizzard it piles up fast. Weather between light snow and a full storm gets a speed in between.
• Never deeper than nature. Snow only refills up to the depth the world generated there, so untouched land never gets buried.
• Snow levels itself out. Banks that walking and shovelling push up settle back down, and snow smooths out with the ground around it, so trampled ground doesn't grow spikes.
• Paths stay clear. Paths you make with the hoe, dirt or stone, never snow over, so you can lay out routes through the Deep North.
• Shelter keeps ground clear. Ground under floors, roofs or rock overhangs, or inside a Shield Generator's dome stays clear. Fires can keep snow away too if you switch that on (fimbul firesnow on): torches and campfires clear 4 m around them, a lit Eternal Pyre 20 m.
• Time away counts. When you come back to an area, or after you sleep, the snow that fell meanwhile is added at the calm rate, so old tracks are already filling in when you arrive.
• Ice freezes over again. Broken Ice Sheets refreeze a piece at a time, growing back from the ice that's left: slowly in clear weather, quickly in a blizzard. A sheet broken completely is kept so it can freeze over too, and sheets the game already deleted (even before you installed the mod) are put back as open water, so the ice returns to the world's original layout. Time you spend away (or asleep) counts too, at the clear-weather pace, and is caught up as soon as you come back. Ice never refreezes within 30 m of a player while you watch, or around a boat or a creature. Docks and other buildings get frozen in like anything else; only heat keeps ice away.
• Fire keeps water open. No ice refreezes within 8 m of a lit fire: torches, campfires, braziers, hearths and other heat sources. A lit Eternal Pyre goes further: it thaws all ice within 40 m and keeps it away, so build one to keep a harbour open.
• Light on performance. Only areas near you are updated, and the terrain is redrawn only once a visible amount of snow has built up.

Snow on buildings isn't changed. It still builds up and causes damage exactly as in vanilla.

Installation

Install with r2modman or the Thunderstore Mod Manager; BepInExPack Valheim is installed automatically as a dependency. No Jötunn needed.

Manual install: put Fimbulvetr.dll in Valheim\BepInEx\plugins\Fimbulvetr\.

Multiplayer: client-side. The dedicated server doesn't need it. Snow comes back in an area while a player who has the mod is in charge of it (usually whoever is standing there). Players without the mod still see the snow come back. To keep things consistent, everyone who visits the Deep North should install it.

Removing the mod: safe at any time. It only changes the snow depth stored in the game's normal terrain data, plus one timestamp per area and per broken ice sheet and a list of path spots per area. Ice sheets broken completely while it was installed stay as open water once it's removed.

Settings

BepInEx\config\com.chase.fimbulvetr.cfg

Setting	Default	What it does
CalmRate	1	cm of snow per real minute when no snow is falling
SnowfallRate	5	cm per minute in the lightest snowfall
StormRate	25	cm per minute in a full blizzard
CatchUpWhileAway	true	add the snow that fell while you were away or asleep
KeepRoofedGroundClear	true	no snow under building pieces or rock overhangs
KeepShieldedGroundClear	true	no snow inside Shield Generator domes
SettleRate	3	cm per minute that snow piled above its natural depth settles back down
Smoothing	0.3	how strongly snow levels out with the ground around it each minute (0 = off)
KeepPathsClear	true	no snow on dirt and stone paths made with the hoe
FiresMeltSnow	false	snow melts and stays away around lit fires
FireSnowReach	4	metres around a lit fire (torches included) kept free of snow
PyreSnowRadius	20	metres around a lit Eternal Pyre kept free of snow
SnowCoversSlopes	true	ground raised by snow always looks like snow, even on slopes and cliff edges, instead of a taller rock face (DirectX 11; on Vulkan the terrain looks vanilla)
MeltRate	20	cm per minute that snow melts around fires, under buildings and on paths
Range	150	metres around you that are updated
MinStepCm	2	how much snow builds up before the terrain is redrawn
RefreezeIce	true	broken Ice Sheets freeze over again
MinutesPerPiece	6	real minutes for one piece of ice to refreeze in light snowfall; scales with the snow rates (about 30 in clear weather, about 1 in a blizzard)
PlayerDistance	30	ice never refreezes this close to a player
HeatKeepsWaterOpen	true	no ice refreezes near fires and other heat sources
FireReach	8	metres around a lit fire (torches included) where ice won't refreeze
EternalPyreThaws	true	a lit Eternal Pyre thaws ice around it and keeps it away
PyreRadius	40	metres kept ice-free around a lit Eternal Pyre
RestoreMissingSheets	true	put back Ice Sheets the game deleted, empty, so they refreeze
LogHitches	false	log frames that take much longer than usual, with what the mod and the terrain did in them

With the defaults, a 1 m deep trench refills in about 4 minutes in a blizzard and in about 1.5 hours of clear weather.

Console command

Open the console with F5 (start the game with -console).

fimbul                  current weather, refill speed, ice sheets and the mod's cost
fimbul storm|snow|calm  force a refill speed, for testing
fimbul off              back to the real weather
fimbul disable|enable   switch the mod off or on (saved to the config)
fimbul firesnow on|off  fires keep snow away, or not (saved to the config)
fimbul slopes on|off    snow-raised ground looks like snow, or as in vanilla
fimbul hitches on|off   log long frames with what the mod did in them

Known limitations

• Tested on a dedicated server with one player. Several players in the Deep North at once is less tested, so bug reports are welcome.
• Snow that fell while an area was unloaded counts at the calm rate, because nobody saw that weather.
• Tracks made before installing the mod only refill while you're nearby.
• A faint line can show at an area's edge if the neighbouring area is in the hands of a player without the mod.
• Ice refreezing and the Eternal Pyre are new in 1.1.0, and snow levelling, clear paths and fires melting snow are new in 1.2.0. All are lightly tested.
• Deleted Ice Sheets are found by replaying world generation. Where the terrain was changed a lot, a sheet can come back slightly off or not at all.
• Not yet tested alongside other mods that change terrain or the Deep North.