Building From a Console or a Script¶

The /lcdev commands that need no player and no game window: bring a building in from a file, look at it, see what changed, generate it and read back what came out.

This page documents the companion mod, not Lost Cities

These commands are in The Lost Cities - DevTool 3.3.0-7.5 only, the file for Lost Cities 7.5.1 to 7.5.6 on Minecraft 1.20.1 with Forge. The NeoForge files do not have them. Every number here was measured on Lost Cities 7.5.6. The rest of /lcdev is on The DevTool Commands. Nothing here is a claim about Lost Cities' behaviour, so it carries no verification chips: it describes a tool this wiki ships.

Everything at a glance¶

Every one needs permission level 2, as the rest of /lcdev does.

Command	What it is for
`/lcdev at <plot> <command>`	Run any command standing on a named plot, in plot coordinates
`/lcdev json <command>`	Run any command and answer with one line of JSON
`/lcdev script <file> [keepgoing]`	Run a file of commands, one a line
`/lcdev schem list`	The building files in the schematics folder
`/lcdev schem info <file>`	A file's size, levels, the row it fits, and blocks the game does not have
`/lcdev schem place <file> [corner] [keep] [missing] [y=<n>] [cellars=<n>]`	Put a file's building on the plot
`/lcdev schem save <name> [replace]`	Write the plot out as a Sponge schematic
`/lcdev look [<from> <to>] [name] [cut=<n>] [scale=<n>]`	A plot, or any box, as pictures, floor plans and text
`/lcdev diff`	The cells of a plot that changed since it was imported or pasted
`/lcdev diff <file> [corner] [y=<n>] [name=<folder>]`	The cells of a plot that are not the file's
`/lcdev diff <file> <x> <y> <z> [name=<folder>]`	The same for any box of any dimension
`/lcdev note <words>`	Leave words on a block
`/lcdev note list`, `/lcdev note clear [all]`	Show them, take them away
`/lcdev verify [radius] [words]`	What Lost Cities chose and generated in a square of chunks
`/lcdev findings [namespace]`	The load check's findings, for one pack or all
`/lcdev profile [set <key> <value> \\| clear <key>]`	The pack's profile keys

Without a player¶

A plot command acts on the plot under the caller, and a console stands on no plot. at puts the command on one.

/lcdev at building/1x1/0 fill ~ ~ ~ ~15 ~ ~15 minecraft:stone_bricks
/lcdev at building/1x1/0 lcdev plot set name tower
/lcdev at core lcdev plot set namespace mypack

Coordinate	Direction	On a one chunk plot
`~x`	East	0 to 15
`~y`	Up, from the first layer a building occupies	0 upward
`~z`	South	0 to 15

A plot is named <row>/<index>, as /lcdev workshop rows lists them. core is the front desk, which holds the settings of the pack as a whole.

json in front of any command gives its answer as data:

{"ok": true, "command": "...", "result": 1, "data": {}, "findings": [],
 "failures": [], "warnings": [], "facts": [], "text": []}

Field	Holds
`ok`	`true` when the command worked and nothing failed
`data`	The answer as numbers, lists and file paths
`failures`	`{subject, where, fix}` for each refusal: what, where, and what to change
`findings`	`{severity, file, namespace, line, message, fix}` for each fault in a pack
`warnings`	Things that exported and will not do what was meant
`text`	Every line as the console shows it

script runs a file from config/lostcitiesdevtool/scripts/, one command a line. Under at every line stands on the plot's corner. It stops at the first line that fails and names it. keepgoing runs them all. A script may run a script, 8 deep.

A building from a file¶

Files are read from config/lostcitiesdevtool/schematics/ and nowhere else.

Format	Is
`.schem`	A Sponge schematic, versions 1 to 3
`.nbt`	What a structure block saves
`.json`	A text building: a palette of characters and layers of rows

Question	What `schem place` does
Larger than the plot	Refuses, with the row that fits
Smaller than the plot	Centres it. `corner` puts it on the plot's corner
What stood there	Saves it under `backups/plots/`, then clears it. `keep` pastes over it
A block the game does not have	Refuses by name. `missing` places the rest
Stairs, panes, fences	Keep the state the file gave them
A block entity's data	Pasted whole. A command block arrives with `auto` off
Entities in the file	Left out and counted
The plot's settings	`floors` and `cellars` are set to the height placed. `cellars=<n>` makes the lowest `n` levels cellars

Lost Cities stacks a building in levels six blocks tall. A height that is not a whole number of levels is one more level, part filled: 21 high is four levels, floors 3.

{
  "format": "lcdev-building",
  "palette": {
    "#": "minecraft:bricks",
    "g": "minecraft:glass_pane[east=true,west=true]",
    "c": {"block": "minecraft:chest[facing=north]", "nbt": "{LootTable:\"minecraft:chests/simple_dungeon\"}"}
  },
  "layers": [
    ["####", "#..#", "#c.#", "####"],
    ["#gg#", "#..#", "#..#", "#gg#"],
    1
  ]
}

Rule	Detail
Layers	Bottom first
Rows in a layer	North to south, so a layer reads as a floor plan with north at the top
Characters in a row	West to east
A layer written as a number	That layer again, counted from 0
A row one character short	Refused, with its layer and row

/lcdev look writes this same format, so a plot can be written out, edited and placed again.

Looking¶

/lcdev look on a plot, or /lcdev look <x1> <y1> <z1> <x2> <y2> <z2> for any box. Files go in config/lostcitiesdevtool/views/<name>/.

File	Shows
`sheet.png`	Each side as seen from outside, and the top, on one image
`plans.png`	A plan of every level of six layers, looking down into it
`blocks.json`	The box as a text building, with any notes left on it

Drawn as	What
Half a square	A slab
A square with its step darker	A stair seen from the front
A line	A pane seen edge on
A dark line down a picture	A chunk edge
A red line across a picture	Every sixth layer, where one level ends

A plan is taken from under a level's ceiling when the level has one in its own top layer. cut=<0 to 5> names the layer to look down from, and scale=<n> the pixels to a block.

A block is drawn in its map colour, which for a mod's blocks is often nothing like the texture. config/lostcitiesdevtool/colours.json gives a block the colour it names:

{"mymod:grey_paving": "#8A8A8A"}

In blocks.json, a palette entry that carries data has it three ways: nbt as text, tag as an object, and lootTable by name when there is one.

What changed¶

Command	Compares
`/lcdev diff`	The plot with how it stood when `import` or `schem place` last filled it
`/lcdev diff <file>`	The plot with a file, set down as `schem place` sets it
`/lcdev diff <file> <x> <y> <z>`	A box with a file whose lowest north west corner is at that block

It reads from the file, or from the plot as it was, to the world as it stands. added is a block the world has and the other side does not.

In a changed cell	Holds
`x`, `y`, `z`	From the box's corner: east, up, south
`kind`	`added`, `removed`, `block`, `state` or `tag`
`was`, `now`	The block with its state
`properties`	Each property that differs, when the block is the same
`wasLootTable`, `nowLootTable`	The loot table on each side
`sideEffect`	`opened` for a container that had a loot table and has none, `toggled` for a door left open. Absent on a change somebody built

Against a file, the world is held to what the file asks for: the properties a text building names, the data keys it gives, and a number by its value. Measured: a door, a chest with a loot table and a command block set to run, pasted and untouched, differ from their file in 0 cells.

/lcdev export writes the same list as changes.json in the export's folder, for every plot filled by an import or a paste, with when and from what it was filled. A plot filled by an older version has nothing to be compared with, and is listed under noBaseline.

/lcdev note <words> leaves words on the block a player is looking at, or from a console on the block the command stands on. look, diff and changes.json hand a note on with its place and the block standing there.

What generated¶

/lcdev verify [radius], run in a dimension Lost Cities generates:

/execute in lostcities:lostcity run lcdev verify 8 mypack

It reports	Detail
Each building chosen	How many chunks, the heights it came in, and up to three copies with the box each stands in
Each multibuilding	Placed whole, with its size in chunks
Buildings never chosen	For each namespace given. A building no city style names is never chosen anywhere
Chunks that failed	The chunk and the reason

Word after the radius	Does
A namespace	Lists that pack's buildings no chunk chose
A building, as `mypack:tower`	Generates that one first
`centre=<x>,<z>`	Puts the middle of the square on that chunk
`samples=<n>`	Up to `n` copies of each building, 1 to 8

The radius is 32 at most. A run generates the first copy of each building, 64 chunks at most. Measured on chunks that did not exist: 5 seconds at radius 8, 8 seconds at radius 32.

/lcdev profile set <key> <value> puts a profile key in the pack. A key Lost Cities does not have is refused, and so is a value of the wrong type.

From a shell¶

lcdev.py drives a server from a command line: start it, stop it, run a command, install an exported pack, restart and report what generated. It is one file with no dependencies, in the agent folder of this repository, beside a guide to every verb and every field.

Verb	Does
`start`, `stop`, `status`	The server itself
`cmd <command>`, `at <plot> <command>`	A command, answered as JSON
`install <pack>`, `uninstall`	Put an exported pack where the next start generates it, and take it out
`verify <pack> [radius]`	Stop, install, start, and report
`survey <dimension> [radius]`	The same report for a pack already in place

Lost Cities reads its buildings as the server starts, so a pack that changed needs a restart. Everything else runs on a server left up.

Not checked¶

What	Why
`note` on the block a player is looking at	The test rig has no player. Notes are left by position there
A file written by `schem save`, opened in WorldEdit	Not tried
`lcdev.py` on Linux or macOS	It ran on Windows only