dota_factory/docs/content_design.md

Content Design — Ships, Modules & Production Tree

The designed game content: hull layout grids, module footprints and the gating between them, and the production tree (items, chains, fiction). All numbers — quantities, durations, threat values, stats, unlock levels — live in the config files and are documented with their derivations in docs/balancing/ (see balancing/README.md for the index).

Design principle: footprint gating

Which module fits on which hull is controlled purely by geometry — no explicit allow-lists. Each hull grid is shaped so that it physically cannot contain the footprint of modules from a larger size class. This keeps the rules transparent to the player ("it doesn't fit because there is no room") and makes them trivially moddable through the config files alone.

Module footprint ladder

Footprint	Modules	Smallest hull that fits it
1x1	railgun_s, salvager, repair_tool	drone
1x2	maneuvering_thrusters, sensor_booster, armor_plates	frigate
1x3	afterburner	frigate (eats most of it)
L-shape (3 cells)	weapon_stabilizer, weapon_primer, weapon_upgrade	frigate
2x2	railgun_m, drone_bay	cruiser
3x3	railgun_l	battleship
2x6	drone_hangar	carrier (only)

Hull grids

O = buildable cell, X = hull structure (not buildable).

drone (xs, 1 cell) — exactly one 1x1 module: a small gun, a salvager, or a repair tool. This is what makes drone roles swappable.

O

frigate (s, 5 cells) — plus shape. Every 1x2 placement crosses the center cell, so at most ONE 1x2 support fits; alternatively one L-shaped weapon modifier or one afterburner through the center line. Gun-boat with one or two support modules, as intended.

XOX
OOO
XOX

destroyer (s, 8 cells) — gun deck with three turret bumps. More cells than the frigate (more small guns), but still no 2x2 area anywhere, so medium hardware can never be mounted.

OXOXO
OOOOO

cruiser (m, 12 cells) — notched corners. Fits at most two 2x2 m guns (stacked through the middle), leaving the side cells for supports. No 3x3 area.

XOOX
OOOO
OOOO
XOOX

battlecruiser (m, 16 cells) — split bow with two gun cheeks, tapered stern. Fits three 2x2 m guns — one more than the cruiser — with small support slots left over. The bow split and stern taper prevent any 3x3 area (no l gun) and any 2x6 area (no drone hangar).

OOXXOO
OOOOOO
XOOOOX
XXOOXX

battleship (l, 24 cells) — broadside hull with notched flanks on every other row. Fits four 2x2 m guns (two per gun deck) — one more than the battlecruiser — with bow, stern, and flank cells for supports. All 3x3 placements crowd the center columns, so at most ONE l gun fits: mounted center it blocks every m gun mount (pure support strips remain), mounted offset it still allows two m guns. The notched rows are never adjacent-and- full, so no 2x6 drone hangar fits.

XOOOOX
OOOOOO
XOOOOX
OOOOOO
XOOOOX

dreadnought (xl, 36 cells) — the main battery deck is split into three 3x3 gun slots by structural spacer columns, so exactly three l guns fit side by side (or m guns / supports in unused slots), plus bow/stern strips for supports. The spacers cap every horizontal run at 5 cells, so the 2x6 drone hangar can never fit — the carrier stays the only hangar hull.

XXXOOOOOXXX
OOOXOOOXOOO
OOOXOOOXOOO
OOOXOOOXOOO
XXOOXXXOOXX

carrier (xl, 37 cells) — the top flight deck (rows 0–1) is the only region wide enough for the 2x6 drone hangar, and exactly one fits. The middle deck row is broken up by elevator shafts (X cells placed so every 3-column window hits one), which is what prevents any 3x3 l gun from ever fitting. Lower decks hold supports and 2x2 point-defense m guns.

XOOOOOOOOX
OOOOOOOOOO
OOXOOXOOXO
XOOOOOOOOX
XXXOOOOXXX

Verified gating matrix

Checked programmatically against the configs (all four mask rotations, all placements) with tools/verify_layouts.py — re-run it after editing layout grids or surface masks:

python dota_factory/tools/verify_layouts.py

Footprint	drone	frigate	destroyer	cruiser	battlecruiser	battleship	dreadnought	carrier
1x1	x	x	x	x	x	x	x	x
1x2		x	x	x	x	x	x	x
1x3		x	x	x	x	x	x	x
L-shape		x	x	x	x	x	x	x
2x2				x	x	x	x	x
3x3						x	x
2x6								x

Maximum simultaneous (disjoint) placements: m guns — cruiser 2, battlecruiser 3, battleship 4; l guns — battleship 1, dreadnought 3; drone hangar — carrier 1.

Production tree

Designed against the rules in docs/balancing/rules.md (ratio curve, cost ladder, cost archetypes, refactorability). Quantities, durations, and threat values live in docs/balancing/derived.md.

Base inputs (4) and fiction

• iron_ore, copper_ore — from the start, minable on every asteroid tile. Fiction: the asteroid is an M-type (metal) body — its bulk rock is ore, which is why the shipyard operation was built here at all.
• quartz — mid-game, minable only on geode deposit patches in expansion territory (see the Resource deposits rules in docs/balancing/rules.md; the deposit mechanic itself is an open action item — until it lands, quartz mines anywhere). Fiction: ordinary silicate dust is everywhere and worthless; chips and optics need rare, pocket-bound optical-grade crystal.
• voidsteel — late-game, obtained only by reprocessing scrap. Fiction: battle-forged — formed when weapon plasma anneals hull metal in the violence of ship destruction. Any wreck yields it, including the player's own; no foundry can replicate it.
• titanium was dropped (v1 tree). Its hull-gating role moved to quartz-era control systems ("you can smelt all the steel you want, but you cannot steer a battlecruiser without electronics") plus the hardened-steel quality step (a deliberately long-running, time-heavy recipe) — explicitly not sheer steel quantity alone.

Material palette (fingerprints per family)

• iron/steel — structure.
• copper — conduction and heat: wiring, coils, heat sinks.
• silicon family (all derived from quartz): silicon (logic, sensors), ceramics (heat shielding, insulators); glass/optics are cut from v1 — their only consumers would be lasers, which are deferred.
• voidsteel — capital-tier structure and exotics.
• Deliberately skipped: carbon (mostly redundant with copper/ceramics), plastics (drags in Factorio-style chemical chains; ceramics read more sci-fi anyway), volatiles/ice (materials are build costs only — no consumption mechanic to justify fuel).

Weapons

• All v1 weapons are railguns (railgun_s/m/l, renamed from the laser placeholders; footprints and the gating matrix unchanged). Implementation is instant damage application with no projectile and no ammunition — the beam visual reads as a tracer round. Materials: iron slugs, copper coils, steel rails — the starting-metal fingerprint.
• Lasers are reserved for later as a genuinely distinct weapon type (e.g. once projectile/ammunition mechanics exist for other families), arriving with quartz optics. More weapon types are planned; railguns are simply the baseline tech that ships with v1.
• drone_bay and drone_hangar are footprint-only placeholders: the drone-launching capability does not exist in the simulation yet, so they define no capability section. The carrier is deliberately weak until that capability lands (see the accepted imbalances in docs/balancing/targets.md).

Tree structure

Input lists only — quantities, durations, and per-item threat values are in docs/balancing/derived.md and the configs.

Mined (miner): iron_ore, copper_ore (every tile), quartz (geode deposits in expansion territory).

Smelted (smelter — exactly one recipe per input item):

output	input	ratio class
iron_ingot	iron_ore	nice (1:1)
copper_ingot	copper_ore	nice
silicon	quartz	mid entry
iron_ingot	scrap	the safe, boring scrap sink

Reprocessing pool (scrap): iron_ingot, copper_ingot, silicon, voidsteel — the only source of voidsteel. Weights authored for the fully unlocked pool state.

Tier 2 — early intermediates (clean ratios, ~2:3):

item	inputs	role
steel_plate	iron_ingot	structure backbone, highest volume
copper_wire	copper_ingot	conductors
copper_coil	copper_wire	electromagnets: railguns, thrusters
building_block	steel_plate	depth-3 chain = the doubling-time knob

Tier 3 — mid intermediates (strange ratios begin, need quartz):

item	inputs	role
control_chip	silicon + copper_wire	electronics gate for m+ hulls
capacitor_bank	copper_coil + silicon	power for railgun m/l
hardened_steel	steel_plate (long cycle)	quality gate for m+ hulls; time-heavy
ceramic_plate	quartz	heat shielding: drives, l guns, capitals
drive_unit	steel_plate + copper_coil + control_chip	propulsion for m+ hulls

Tier 4 — late intermediates (need voidsteel):

item	inputs	role
voidsteel_plate	voidsteel + hardened_steel	capital structure
capital_core	voidsteel + capacitor_bank + control_chip	capital heart

Hull items (<ship>_hull, assembler-made; the shipyard consumes the hull item plus module materials). The m+ hull gate is both hardened_steel (quality steel, the time-heavy step) and control_chip (electronics):

hull	inputs
drone_hull	iron_ingot
frigate_hull	steel_plate + copper_wire
destroyer_hull	steel_plate + copper_coil
cruiser_hull	hardened_steel + control_chip
battlecruiser_hull	hardened_steel + control_chip + drive_unit
battleship_hull	voidsteel_plate + drive_unit + control_chip
dreadnought_hull	voidsteel_plate + capital_core + drive_unit
carrier_hull	voidsteel_plate + capital_core + drive_unit

Module items (<module>_module, assembler-made prefabs — kept as items so shipyard belt inputs stay simple and module production can be stockpiled):

module	inputs	archetype
railgun_s	copper_coil	lean
salvager	steel_plate + copper_wire	balanced
repair_tool	steel_plate + copper_wire	balanced
armor_plates	steel_plate (many)	material-heavy, fast
maneuvering_thrusters	steel_plate + copper_coil	balanced
sensor_booster	copper_wire + copper_coil	lean (an antenna, no chip)
afterburner	copper_coil + steel_plate	balanced
weapon_stabilizer	steel_plate + copper_coil	balanced
weapon_primer	capacitor_bank + copper_coil	mid; time-heavy
weapon_upgrade	control_chip + copper_coil	mid; time-heavy
railgun_m	capacitor_bank + steel_plate + copper_coil	mid
drone_bay	control_chip + steel_plate + copper_coil	mid
railgun_l	capacitor_bank + hardened_steel + ceramic_plate	late
drone_hangar	voidsteel_plate + control_chip + drive_unit	late (carrier only)

Refactorability check (the default technique holds): railgun_s → m introduces capacitor_bank, built from a subset of the small gun's inputs (copper_coil) plus the new base resource (silicon); the m gun otherwise reuses the small gun's inputs. Hulls likewise: the cruiser adds hardening (fed by the existing steel line) and chips (fed by the new quartz territory) without touching the iron/copper core.

Shortcut recipes (drop-only assembler schematics; not every strange chain gets one): iron_ore → steel_plate (skips the ingot step on the highest-volume chain), quartz → control_chip (skips silicon), iron_ingot → hardened_steel (a nicer-ratio route past the deliberately awkward hardening step).

Consistency is checked by tools/verify_recipes.py — re-run it after editing recipes, ship/module materials, or visuals:

python dota_factory/tools/verify_recipes.py

It verifies every consumed item has a producer, every item has a visuals entry, flags orphaned items, and prints which items are reprocessing-only (currently exactly voidsteel).