TimeControl

TimeControl

A BepInEx 5 plugin for Valheim that adjusts the length of the in-game

day/night cycle with a single multiplier.

By default Valheim runs one full day/night cycle in roughly 30 real minutes.

TimeControl lets you stretch (or compress) that — e.g. a 4.0 multiplier turns

a full day into about 2 real hours.

How it works

Valheim derives the time of day every physics tick from a single field,

EnvMan.m_dayLengthSec:

dayFraction = (worldClockSeconds mod m_dayLengthSec) / m_dayLengthSec

The networked world clock advances at a fixed rate of 1 real second to 1 game

second, so making a day longer is simply a matter of increasing

m_dayLengthSec. TimeControl captures Valheim's shipped value once and

multiplies it by your configured multiplier. Day and night both scale together;

their ratio is fixed by Valheim and is preserved.

The change takes effect immediately and smoothly — the sun does not jump.

On-screen clock

TimeControl shows a small clock in the top-center of the screen that displays the

current time of day as a single word — Midnight, Night, Dawn, Morning,

Midday, Afternoon, or Dusk. The word is derived from Valheim's own

day fraction, so it lines up with the real sunrise (0.25), midday (0.5) and sunset

(0.75) points of the cycle. It is display-only and per-client — it reads your local

clock and adds no network traffic and no Harmony patches.

The clock's appearance is configurable (color, custom hex color, size, style and

font); see the Clock Appearance options below. The clock's style and font are

rebuilt only when you change a setting, so it adds no measurable per-frame cost.

Configuration

Config file: BepInEx/config/drummercraig.time_control.cfg

| Section | Key | Default | Description |

|---|---|---|---|

| General | DayLengthMultiplier | 4.0 | Multiplier on the vanilla day length. 1.0 = vanilla (~30 min/day). 2.0 = twice as long. Range 0.1–100. |

| General | ShowClock | true | Show the on-screen time-of-day word clock. |

| Clock Appearance | TextColor | White | Palette color for the clock text. Ignored when TextColorHex is set to a valid value. |

| Clock Appearance | TextColorHex | (blank) | Optional custom color as #RRGGBB; overrides TextColor when valid. Blank uses the palette. |

| Clock Appearance | FontSize | 16 | Font size (dropdown of preset sizes: 12, 14, 16, 18, 20, 24, 28). |

| Clock Appearance | FontStyle | Bold | Normal, Bold, Italic, or BoldAndItalic. |

| Clock Appearance | Font | Default | Font family. Default = the built-in game UI font; other entries are common cross-platform fonts, falling back to the default if not installed on your machine. |

You can edit these live from the in-game Configuration Manager (if installed);

changes apply on the spot.

Multiplayer

m_dayLengthSec is a client-local field — vanilla Valheim never sends it

over the network. To keep everyone on the same clock, TimeControl:

• Requires an exact mod-version match. When a client connects, the server

and client exchange their TimeControl version over a custom RPC. If they do

not match exactly — or if one side does not have the mod at all — the

connection is refused with Valheim's native "Incompatible version" screen.

This reuses the same mechanism vanilla itself uses to reject mismatched

clients (ZNet.RPC_PeerInfo + the ConnectionStatus.ErrorVersion code); no

third-party config-sync library is bundled.

• Server settings win. Immediately after the handshake, the server pushes

its effective DayLengthMultiplier to the client, which adopts it for the

session. A connected client's own local config is ignored while connected, so

all players always share the server's clock. The client's local value applies

again in singleplayer or when hosting.

Install TimeControl on the server and on every client, at the same version.

Building

Requires Mono with the.NET Framework 4.8 reference assemblies. TimeControl does

not commit any game/BepInEx DLLs; it references them from your live Valheim

install so it always builds agai