SandTools/docs/PRODUCTION_LINES.md

World factory "production lines" (conveyors) — where to find them

The game has fixed single-recipe world structures — item conveyors that run one recipe (e.g. 1 Raw Aurogen Crystal → 10 Energy Rods). These are a separate mechanic from the player workbench recipes (which live in extracted/crafting_recipes.json, sourced from CraftingRecipeBundle assets). This note records where they live so the data can be re-derived after a game update.

The mechanic

In code it's a "Factory Production Line". It's an Entitas ECS feature, namespace Hologryph.Sand.Shared.Game.Features.Crafting (see il2cpp/dump.cs):

Class	Holds
ProductionLineComponent	int inputEntityIndex, int outputEntityIndex
ProductionLineRecipeComponent	CraftingRecipe recipe ← the recipe
ProductionLineInputDataComponent / …OutputDataComponent	bool isLargeItem{Input,Output}
CraftingRecipe	CraftingIngredient[] inputIngredients, CraftingIngredient[] outputIngredients, float craftingTimeSeconds
CraftingIngredient	string itemId, int amount

Note CraftingRecipe / CraftingIngredient are the same types the workbench uses — only the container differs (a workbench holds List<CraftingRecipeBundle> recipeBundles; a production line holds a single CraftingRecipe on the entity).

Where the data lives

• Bundle: epb_assets_all.bundle (reachable via the bundles/ symlink).
• Prefabs: game_conveyor_*_epb.prefab, under Assets/Content/Game/game_conveyor/.... 14 carry a real recipe; the game_conveyor_base* ones are template/test conversions (cf. TestRecipesBundle).
• Serialization: each prefab GameObject (m_Name = game_conveyor_<x>_epb) has two components — a Transform and a MonoBehaviour whose script is EntityBlueprint. EntityBlueprint : SerializedMonoBehaviour (Sirenix Odin), so the component data — including the CraftingRecipe — is in its Odin-serialized serializationData.SerializedBytes, not in plain typetree fields. (Same situation as the loot tables — see TASK.md / extract_loot.py.)

Extraction path (how to read it)

UnityPy (with an IL2CPP TypeTreeGenerator over GameAssembly.dll + global-metadata.dat) reads the EntityBlueprint MonoBehaviour → pull serializationData.SerializedBytes → bundle/odin_read.py parses the Odin binary → walk the tree for the node with inputIngredients / outputIngredients.

venv/bin/python bundle/extract_production_lines.py   # -> extracted/production_lines.json

Key item ids seen here: item_crystalHandles = Raw Aurogen Crystal, item_energyBar = NZ Mk2 Energy Rod, item_blackBox = Black Box, item_resourceCoralPiece = Coral Chunk. Resolve any id → display name via extracted/items_registry.json / extracted/item_names.json (built from CheatItemDefinitionsData).

Island placement — open lead

Which factory/island runs which conveyor is grouped by the energy_grid_*_epb.prefab blueprints in the same bundle: Wunderinsel, Kaiserplatz, DeusExMachine, Factorio, LittleFactory1-3, LittleFactoryArmory1-3, TestFactory. The …Armory groups are the likely Sprengstofffabrik (explosives factory) host for the explosive / grenade / rocket / cannon conveyors.

Not yet resolved: an energy_grid_* blueprint's Odin data references its conveyors by entity reference, not item-id string (a string scan of its serialized bytes finds no game_conveyor_* / item_* ids). So mapping recipe → specific island needs the island prefab placements in islands_assets_all.bundle (the island_* / fort / loc_event_* prefabs, where Sprengstofffabrik is an i2 Toponyms/ name), not the conveyor or energy_grid EPBs alone. That linkage is the next step if island attribution is wanted.