Wikis / MythicSeasons / Atmosphere / Options

Options

The top of atmosphere.yml holds the master switch, grid, timing, season blend and per-world overrides. Other sections have their own pages:

Section	Page
`biome-defaults`, `weather`	Weather
`season-adjustments`	Season Adjustments
`physics`	Physics
`forcing`	Forcing
`clouds`	Cloud Options

Missing keys come back with their shipped value when the file loads, so to cancel a setting, give it a value that changes nothing.
A file with a YAML error is left alone and the console says atmosphere.yml could not be read. Until you fix it, the simulation runs on the built-in defaults.

Master switch

Option	Default	What it does
`enabled`	`true`	Turns the whole simulation on or off, also on `/ms reload`. While it is off, players and the weather conditions get the server's weather.
`shared-weather-group`	`auto`	Which servers behind MythicProxy share one weather per world: `auto` (from the server name), `none` (never share) or a group name. Needs a restart. See Shared Weather.

The simulation starts in a world when the world first gets a season, and /ms atmosphere toggle <world> switches it per world. A world switched on while enabled is false has no simulated weather, but still skips the season's own random rain (daily-extra-downfall-chance).

Grid

Weather is simulated in cells around the players. 16 x 16 cells make a region (512 blocks on a side at the default cell size), and regions nobody is near freeze.

Option	Default	What it does
`grid.cell-size.xz`	`32`	Size of a cell along x and z in blocks, a power of two from 4 to 512. Halving it gives four times the cells. Needs a restart.
`grid.cell-size.y`	`16`	Height of a cell (one level of the sky), 4 to 64 blocks. Larger gives fewer levels and a lower cost. Needs a restart.
`grid.y-min`	`world`	Lowest block Y of the simulated sky. `world` is the world's lowest block. Needs a restart.
`grid.y-max`	`world`	Highest block Y of the simulated sky. `world` is the build height. Needs a restart.
`grid.max-cells`	`2000000`	Most cells simulated at once per world, 100,000 to 100,000,000. Lower it to cut CPU and memory use. Applies on `/ms reload`.

An xz that is not a power of two is rounded down (300 becomes 256), and values outside the ranges move to the nearest end, both with a warning.
The sky has (y-max - y-min) / cell-size.y levels (rounded down, 8 to 128), 24 on a default overworld. The console prints the real numbers for each world at start.
For max-cells, one player needs about 2,000,000 cells at the default cloud quality on a default overworld (about 740,000 with clouds off). A million cells take about 50 MB of memory.
When far-apart players need more cells than max-cells, the outer edges of their areas go first and the weather there is less developed.
Servers that share weather need the same cell sizes, y-min, number of levels, timing values and world seed.

Timing

Option	Default	What it does
`timing.step-period-ms`	`2000`	Real milliseconds between two simulation steps, at least 250. Higher is lighter on the server, with bigger and rarer updates. Needs a restart.
`timing.time-acceleration`	`4`	Weather seconds per real second, 0 to 64. Higher makes the weather develop faster, up to the limit below. 0 freezes the weather. Needs a restart.

One step moves weather time on by step-period-ms / 1000 x time-acceleration seconds (8 with the defaults), never more than 12. So at the default period any acceleration above 6 acts like 6. Weather time is separate from the day length.

Transition between seasons

Option	Default	What it does
`transition.blend-days`	`3`	In-game days at the end of each season over which its atmosphere settings fade into the next season's starting values. 0 or less switches at the season change.

Numbers fade evenly, but the list of cloud layers switches halfway.
A season file can set its own transition.blend-days in its atmosphere: block, or transition.blend-percent (0 to 100 percent of the season, wins when both are set). Worlds and profiles cannot.
The next season is the next one in season-cycle of config.yml. A season that is not in the cycle does not blend.
/ms atmosphere profile and <mythicseasons.seasonblend> (0.00 to 1.00) show how far the blend has gone.

Per-world overrides

worlds holds one block per world name (not case-sensitive). A block takes any setting a season's atmosphere: block takes, plus cloud-layers.<file name> for one cloud layer and profile: <name> for a file from the atmosphere-profiles folder, used in every season.

worlds:
  resource_world:
    physics:
      max-wind: 25.0
  red_planet:
    profile: mars

worlds does not switch a world on. Use /ms atmosphere toggle <world>.

Settings apply in this order, each over the one before:

The built-in default.
atmosphere.yml itself.
The settings directly under worlds.<world>.
season-adjustments.<season>.
The profile named by atmosphere.profile in the season file.
The atmosphere: block of the season file.
The profile named by worlds.<world>.profile.
The atmosphere.worlds.<world> block of the season file.
Profiles pushed at runtime by the atmosphereprofile mechanic (higher priority wins).

So a setting directly under a world loses to the same setting in season-adjustments or a season file, and the shipped season-adjustments set temperature and humidity for every season. To win over the season, use a world profile or the season file's worlds block, see Profiles.

Value forms

Settings in season, world and profile blocks take these forms:

Written as	Meaning
`0.5` or `"=0.5"`	Sets the value
`"*1.4"`	Multiplies the value so far
`"/2"`	Divides it (dividing by 0 is ignored with a warning)
`"+3"`, `"-3"`	Adds or subtracts
`{START: 0.8, MIDDLE: 1.2, END: 1.0}`	Keyframes: the value at chosen points of the season
`"(1 + 0.1 month)"`	A formula with calendar values or MythicMobs placeholders, see Formulas

Quote operators. An unquoted *1.4 is a YAML error: in atmosphere.yml none of the file's settings apply, and in a season file the season does not load. An unquoted -3 or +3 is a plain number and sets the value.
Keyframe keys are a percentage of the season (0 to 100) or a phase name, meaning the middle of that phase. Values blend between keyframes and hold before the first and after the last.
Every result is kept inside the setting's range without a message.

Settings only atmosphere.yml can hold

Only atmosphere.yml itself can hold these settings. In a world, season or profile block they are ignored with a console message: enabled, shared-weather-group, grid, timing, physics.solver-threads, season-adjustments, forcing.air-masses.size, .speed and .direction, and the cloud settings clouds.enabled, render-distance, lod-level, occlusion-culling, fov-cull-angle, biome-colors, shader-pack and quality.

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